Add issues and comment threads (Phase 3)

Issues: per-project numbers, statuses (open, accepted, rejected,
withdrawn, duplicate), feature links, edits, and a timeline of comments
and events. From an issue, collaborators create or update a feature
with the revision tied to the issue and an option to accept it.

Comments: general and line-anchored threads on features, one
discussion thread per issue, edit history, tombstone deletes, resolve,
and promoting a feature thread to an issue. Line threads attach to
top-level Markdown blocks and go outdated only when the text changes.

HTMX swaps threads in place with focus management; every action also
works as a plain form post. Markdown headings are re-levelled so user
text never skips heading levels on the page.

The example flow from concept.md (steps 1-7) is covered end to end in
tests/test_example_flow.py.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

config/settings/base.py

@@ -29,6 +29,8 @@ INSTALLED_APPS = [
     "intent.orgs",
     "intent.projects",
     "intent.features",
+    "intent.issues",
+    "intent.comments",
 ]
 
 MIDDLEWARE = [

config/urls.py

@@ -32,4 +32,6 @@ urlpatterns = [
     path("<slug:org_slug>/", include("intent.orgs.urls")),
     path("<slug:org_slug>/<slug:project_slug>/", include("intent.projects.urls")),
     path("<slug:org_slug>/<slug:project_slug>/features/", include("intent.features.urls")),
+    path("<slug:org_slug>/<slug:project_slug>/issues/", include("intent.issues.urls")),
+    path("<slug:org_slug>/<slug:project_slug>/", include("intent.comments.urls")),
 ]

docs/plan.md

@@ -22,16 +22,17 @@ Decisions made in the concept are not repeated. These fill the gaps.
 | Feature revision | Integer starting at 1, incremented by every commit to the feature: description edit, file add/replace/remove, parent change, status change. Each revision stores the full description text (not a diff); diffs are computed on display. |
 | Commit note | Required, short, free text. Optionally linked to one or more issues. |
 | Issue ↔ feature | Many-to-many. An issue promoted from a comment thread is linked to that thread's feature. Accepting an issue that creates a feature links both. |
-| Issue statuses | `open`, `accepted`, `rejected`, `withdrawn` (author closes), `duplicate` (links to another issue). Collaborators can reopen. |
+| Issue statuses | `open`, `accepted`, `rejected`, `withdrawn` (author closes), `duplicate` (links to another issue). Collaborators can reopen any closed issue; authors can withdraw their own open issue and reopen it only if they withdrew it. Duplicate chains can't loop. Every status change, feature link and edit is an `IssueEvent` shown in the issue's timeline between comments; edits keep the previous title and text. Closed issues still take comments. |
+| Issue → feature | From an issue, a collaborator follows "Create a feature from #N" or "Update INT-3 for #N". The feature form opens prefilled (title and description from the issue, or a change note naming it), ties the new revision to the issue, links the feature, and offers a checked "Mark #N accepted" box. Accept and Reject buttons also work on their own. |
 | Feature statuses | `active`, `withdrawn`, `superseded` (requires `superseded_by` feature). |
 | Implementation status | `active`, `archived`. |
 | Feature × implementation status | `n/a`, `not_started`, `in_progress`, `shipped`, `retired`; stamped with the feature revision it applies to. Missing row displays as `not_started @ —`. If stamped revision < current revision, display "behind". |
 | Hierarchy | Single optional parent within the same project. Cycles rejected. Moving a feature records a revision. Statuses independent in V1. |
 | Files | Belong to a feature, typed `prototype` or `documentation`. Replacing a file creates a new file version and a feature revision; old versions stay (so old image-pin threads still resolve). Size cap 25 MB; allowed types: images, PDF, markdown/text, HTML, zip. |
-| Line-anchored threads | Anchor = feature revision + start/end source line. On later revisions the thread shows as "outdated" with a link to the revision it was made on; no attempt to re-map lines. |
+| Line-anchored threads | Anchor = feature revision + start/end source line of one top-level Markdown block (paragraph, list, heading, code block). Each block has its own `<details>` comment form, so it works without JS. A thread goes "outdated" only when the description text has changed since its revision (a status-only revision doesn't outdate it); outdated threads move to "Comments on earlier revisions", quote their original lines, and link to the revision. No attempt to re-map lines. A line comment posted against a stale revision is refused and the draft is shown back. |
 | Image threads | Anchor = file version + x/y as fractions (0–1). |
-| Comments | Edits keep history (visible "edited" link). Author or project owner may delete; a deleted comment shows as a tombstone. Resolving a thread is allowed for the thread author or any collaborator. |
+| Comments | Edits keep history (visible "edited" link to a history page). Author or project owner may delete; a deleted comment shows as a tombstone and its text and history are removed. Delete asks for confirmation in a disclosure, so it works without JS. Resolving a feature thread is allowed for the thread author or any collaborator; resolved threads start collapsed. An issue has exactly one thread, its discussion, which isn't resolvable (the issue status says that). |
-| Thread → issue | Original commenter or any team member. Thread gets `promoted_to` issue; issue body is prefilled with the thread text and links back. |
+| Thread → issue | Original commenter (while they can contribute) or any project collaborator. Thread gets `promoted_to` issue and is resolved; the issue is linked to the thread's feature, its body is prefilled with the quoted lines and comments, and its page links back to the thread. |
 | Deleted users | Content remains, attributed to a "ghost" user. |
 | Moderation | Project owners can delete comments and close issues in their project. Sysadmin can deactivate a user site-wide. |
 | Invites | By email or existing username. Username invites appear on the invitee's Invitations page (no notifications in V1). Email invites send a link carrying a random token (only its hash is stored); the link requires sign-in and the first signed-in visitor claims the invite with whatever account they used. Claiming rotates the token, so the link (which appears in request logs) is dead after one use; the claimant then accepts or declines from their Invitations page. Unclaimed email invites also appear on the Invitations page of a user with that verified email. Re-inviting replaces the pending invite. Sending is throttled (30 per sender per hour, 3 per recipient per org per hour). Expire after 14 days. The last org owner cannot be removed, demoted or leave. |
@@ -51,7 +52,7 @@ Decisions made in the concept are not repeated. These fill the gaps.
 | Cache | Django's database cache (`createcachetable` runs at start). It holds allauth's rate limits and the invite throttle, so it must be shared by all gunicorn workers and survive restarts; the database is the only shared store on a one-machine deploy. Dev and tests use the in-memory cache. |
 | Database | SQLite on a Fly volume. `transaction_mode = "IMMEDIATE"`, WAL mode, `busy_timeout` 5 s. Litestream replicates to B2 continuously. |
 | Files | Tigris via `django-storages` S3 backend, private bucket, time-limited signed URLs. HTML prototypes are shown in a sandboxed `<iframe>` whose `src` is a signed URL on the Tigris origin, never rendered inline on the app origin. |
-| Markdown | `markdown-it-py` with source line mapping (`data-line` attributes on blocks) for line threads; output sanitized with `nh3`. Diffs via `difflib` rendered server-side. |
+| Markdown | `markdown-it-py` with source line mapping (`data-source-lines` attributes on blocks) for line threads; output sanitized with `nh3`. Descriptions render block by block so each block can carry its threads. Diffs via `difflib` rendered server-side. |
 | Frontend | Django templates, HTMX for partial updates, Alpine for small local state (image pin placement, thread forms). CodeMirror 6 as a progressive enhancement on the markdown textarea, optional. No build step beyond copying vendored JS into static files. |
 | Email | `django-anymail` with the provider pluggable; console backend in development. **Provider TBD; launch blocker for magic links and email invites.** |
 | Background work | None. Email is sent synchronously. |
@@ -71,7 +72,8 @@ The app should look close to unstyled HTML. Guiding rule: if the stylesheet fail
 - Keyboard: all actions reachable by tab; skip link to `<main>`; visible focus. Image pins get a list alternative (threads listed below the image with coordinates). Line threads have a per-line "comment" button, not hover-only.
 - Contrast and semantics checked with axe in the Playwright smoke tests.
 - Until then, unit tests run a structural check (`tests/a11y.py`) on every page: `lang`, one `<h1>`, no skipped heading levels, unique ids, labelled form controls, `alt` on images. New pages get added to `tests/test_a11y.py`.
-- Markdown headings render one level down (`#` becomes `<h2>`) so user text never adds a second `<h1>`.
+- Markdown headings are re-levelled so the shallowest heading in the text lands one below the surrounding page heading (`<h2>` in descriptions and issue bodies, `<h3>` in comments), keeping relative structure. User text never adds a second `<h1>`, and a comment starting at `##` doesn't skip a level.
+- After an HTMX swap, focus moves to the new or edited comment, or to the thread (`data-autofocus`, `static/js/intent.js`).
 
 ## 3. Data model
 
@@ -88,18 +90,20 @@ ProjectMembership    project, user, role ∈ {owner, collaborator}
 Feature              project, number, parent (nullable, same project), title, status, superseded_by,
                      current_revision (int), created_by
 FeatureRevision      feature, revision, description_md, note, author, parent_at_revision,
-                     status_at_revision, issues (M2M)
+                     status_at_revision   (issues via Issue.revisions)
 FeatureFile          feature, kind ∈ {prototype, documentation}, name, current_version
 FeatureFileVersion   file, version, storage_key, content_type, size, created_in_revision
 Implementation       project, name, url, status ∈ {active, archived}
 FeatureImplStatus    feature, implementation, status, feature_revision, updated_by   (unique feature+impl)
-Issue                project, number, title, body_md, author, status, duplicate_of,
+Issue                project, number, title, body_md, author, status, duplicate_of, closed_at,
-                     features (M2M), promoted_from_thread (nullable)
+                     features (M2M), revisions (M2M FeatureRevision)
-CommentThread        project, target: one of {feature, feature_line, feature_file, file_image_point, issue},
+IssueEvent           issue, actor, kind ∈ {status, linked, unlinked, revision, edited}, status,
-                     feature, issue, revision, line_start, line_end, file_version, x, y,
+                     previous_status, duplicate_of, feature, revision, old_title, old_body
-                     resolved_by, resolved_at, promoted_to (issue)
+CommentThread        project, kind ∈ {feature, line, issue} (Phase 4 adds file, image point),
-Comment              thread, author, body_md, deleted_at
+                     feature, issue, revision, line_start, line_end, author,
-CommentEdit          comment, body_md, edited_at
+                     resolved_by, resolved_at, promoted_to (OneToOne issue)
+Comment              thread, author, body_md, edited_at, deleted_at, deleted_by
+CommentEdit          comment, body_md (text before the edit), created_at
 ```
 
 Notes:
@@ -123,7 +127,9 @@ Resolved per request into a small `Access` object (`can_view`, `can_comment`, `c
 | Accept/reject/reopen issue | | | | ✓ | ✓ |
 | Create/edit feature, files, status | | | | ✓ | ✓ |
 | Link implementations, set statuses | | | | ✓ | ✓ |
-| Resolve threads, delete comments | own | own | own | ✓ | ✓ |
+| Resolve feature threads | | own | own | ✓ | ✓ |
+| Edit comments, withdraw issues | | own | own | own | own |
+| Delete comments | | own | own | own | ✓ |
 | Manage project members, delete project | | | | | ✓ |
 | Create project | | | if `can_create_projects` | | org owner ✓ |
 | Manage org members, grants | | | | | org owner |
@@ -172,6 +178,7 @@ Each phase ends deployable. Rough sizes assume one person, part-time; adjust fre
 - Promote thread to issue.
 - HTMX partials for posting comments and resolving threads, with form fallbacks.
 - **Exit:** the example flow in concept.md (steps 1–7) works end to end.
+- Done: `tests/test_example_flow.py` drives steps 1–7 (and the rejected alternative) through the views. HTMX reply, edit, resolve and the issue timeline were also checked once in headless Chromium; Playwright tests proper are Phase 5.
 
 ### Phase 4 — Files and implementations (medium)
 

intent/access.py

@@ -106,3 +106,48 @@ def visible_projects(user, org: Organization):
     return projects.filter(
         Q(visibility__in=[Visibility.PUBLIC, Visibility.AUTHENTICATED]) | Q(memberships__user=user)
     ).distinct()
+
+
+# Object-level rules for issues and comments. `access` is the user's ProjectAccess for the
+# object's project. Authors keep rights over their own words only while they can still see
+# (or, for edits, contribute to) the project.
+
+
+def is_author(user, author_id) -> bool:
+    return _is_regular_user(user) and author_id is not None and author_id == user.pk
+
+
+def can_edit_issue(user, access: ProjectAccess, issue) -> bool:
+    return access.can_edit or (is_author(user, issue.author_id) and access.can_contribute)
+
+
+def can_withdraw_issue(user, access: ProjectAccess, issue) -> bool:
+    """Authors close their own open issues, and may reopen ones they withdrew."""
+    return is_author(user, issue.author_id) and access.can_view
+
+
+def can_resolve_thread(user, access: ProjectAccess, thread) -> bool:
+    from intent.comments.models import ThreadKind
+
+    if thread.kind == ThreadKind.ISSUE:
+        return False  # An issue's status says whether its discussion is done.
+    return access.can_edit or (is_author(user, thread.author_id) and access.can_view)
+
+
+def can_promote_thread(user, access: ProjectAccess, thread) -> bool:
+    from intent.comments.models import ThreadKind
+
+    if thread.kind == ThreadKind.ISSUE or thread.promoted_to_id:
+        return False
+    return access.can_edit or (is_author(user, thread.author_id) and access.can_contribute)
+
+
+def can_edit_comment(user, access: ProjectAccess, comment) -> bool:
+    return not comment.is_deleted and is_author(user, comment.author_id) and access.can_contribute
+
+
+def can_delete_comment(user, access: ProjectAccess, comment) -> bool:
+    """Authors delete their own comments; project owners moderate."""
+    if comment.is_deleted:
+        return False
+    return access.can_admin or (is_author(user, comment.author_id) and access.can_view)

intent/comments/admin.py

@@ -0,0 +1,29 @@
+from django.contrib import admin
+
+from .models import Comment, CommentThread
+
+
+class CommentInline(admin.TabularInline):
+    model = Comment
+    extra = 0
+    can_delete = False
+    fields = ["created_at", "author", "body", "edited_at", "deleted_at"]
+    readonly_fields = fields
+
+    def has_add_permission(self, request, obj=None):
+        return False
+
+
+@admin.register(CommentThread)
+class CommentThreadAdmin(admin.ModelAdmin):
+    """Read-only: moderation happens in the app, where it leaves a tombstone."""
+
+    list_display = ["__str__", "project", "author", "created_at", "resolved_at"]
+    list_filter = ["kind"]
+    inlines = [CommentInline]
+
+    def has_add_permission(self, request):
+        return False
+
+    def has_change_permission(self, request, obj=None):
+        return False

intent/comments/apps.py

@@ -0,0 +1,6 @@
+from django.apps import AppConfig
+
+
+class CommentsConfig(AppConfig):
+    name = "intent.comments"
+    label = "comments"

intent/comments/forms.py

@@ -0,0 +1,23 @@
+from django import forms
+
+from .services import MAX_BODY
+
+
+class CommentForm(forms.Form):
+    body = forms.CharField(max_length=MAX_BODY, widget=forms.Textarea)
+
+
+class LineThreadForm(CommentForm):
+    revision = forms.IntegerField(min_value=1)
+    line_start = forms.IntegerField(min_value=1)
+    line_end = forms.IntegerField(min_value=1)
+
+
+class PromoteForm(forms.Form):
+    title = forms.CharField(max_length=200)
+    body = forms.CharField(
+        label="Description",
+        required=False,
+        widget=forms.Textarea(attrs={"rows": 16, "cols": 80}),
+        help_text="Markdown. Starts as a quote of the thread; trim it to what matters.",
+    )

intent/comments/migrations/0001_initial.py

@@ -0,0 +1,66 @@
+# Generated by Django 5.2.18 on 2026-10-27 12:49
+
+import django.db.models.deletion
+import intent.core.models
+from django.conf import settings
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    initial = True
+
+    dependencies = [
+        ('features', '0002_initial'),
+        migrations.swappable_dependency(settings.AUTH_USER_MODEL),
+    ]
+
+    operations = [
+        migrations.CreateModel(
+            name='Comment',
+            fields=[
+                ('id', intent.core.models.ULIDField(default=intent.core.models.new_ulid, editable=False, max_length=26, primary_key=True, serialize=False)),
+                ('created_at', models.DateTimeField(auto_now_add=True)),
+                ('updated_at', models.DateTimeField(auto_now=True)),
+                ('body', models.TextField(blank=True)),
+                ('edited_at', models.DateTimeField(blank=True, null=True)),
+                ('deleted_at', models.DateTimeField(blank=True, null=True)),
+                ('author', models.ForeignKey(null=True, on_delete=django.db.models.deletion.SET_NULL, related_name='+', to=settings.AUTH_USER_MODEL)),
+                ('deleted_by', models.ForeignKey(blank=True, null=True, on_delete=django.db.models.deletion.SET_NULL, related_name='+', to=settings.AUTH_USER_MODEL)),
+            ],
+            options={
+                'ordering': ['created_at', 'id'],
+            },
+        ),
+        migrations.CreateModel(
+            name='CommentEdit',
+            fields=[
+                ('id', intent.core.models.ULIDField(default=intent.core.models.new_ulid, editable=False, max_length=26, primary_key=True, serialize=False)),
+                ('created_at', models.DateTimeField(auto_now_add=True)),
+                ('updated_at', models.DateTimeField(auto_now=True)),
+                ('body', models.TextField()),
+                ('comment', models.ForeignKey(on_delete=django.db.models.deletion.CASCADE, related_name='edits', to='comments.comment')),
+            ],
+            options={
+                'ordering': ['created_at', 'id'],
+            },
+        ),
+        migrations.CreateModel(
+            name='CommentThread',
+            fields=[
+                ('id', intent.core.models.ULIDField(default=intent.core.models.new_ulid, editable=False, max_length=26, primary_key=True, serialize=False)),
+                ('created_at', models.DateTimeField(auto_now_add=True)),
+                ('updated_at', models.DateTimeField(auto_now=True)),
+                ('kind', models.CharField(choices=[('feature', 'Feature'), ('line', 'Lines of a feature description'), ('issue', 'Issue')], max_length=20)),
+                ('revision', models.PositiveIntegerField(blank=True, null=True)),
+                ('line_start', models.PositiveIntegerField(blank=True, null=True)),
+                ('line_end', models.PositiveIntegerField(blank=True, null=True)),
+                ('resolved_at', models.DateTimeField(blank=True, null=True)),
+                ('author', models.ForeignKey(null=True, on_delete=django.db.models.deletion.SET_NULL, related_name='+', to=settings.AUTH_USER_MODEL)),
+                ('feature', models.ForeignKey(blank=True, null=True, on_delete=django.db.models.deletion.CASCADE, related_name='threads', to='features.feature')),
+            ],
+            options={
+                'ordering': ['created_at', 'id'],
+            },
+        ),
+    ]

intent/comments/migrations/0002_initial.py

@@ -0,0 +1,53 @@
+# Generated by Django 5.2.18 on 2026-10-27 12:49
+
+import django.db.models.deletion
+from django.conf import settings
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    initial = True
+
+    dependencies = [
+        ('comments', '0001_initial'),
+        ('issues', '0001_initial'),
+        ('projects', '0001_initial'),
+        migrations.swappable_dependency(settings.AUTH_USER_MODEL),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name='commentthread',
+            name='issue',
+            field=models.ForeignKey(blank=True, null=True, on_delete=django.db.models.deletion.CASCADE, related_name='threads', to='issues.issue'),
+        ),
+        migrations.AddField(
+            model_name='commentthread',
+            name='project',
+            field=models.ForeignKey(on_delete=django.db.models.deletion.CASCADE, related_name='threads', to='projects.project'),
+        ),
+        migrations.AddField(
+            model_name='commentthread',
+            name='promoted_to',
+            field=models.OneToOneField(blank=True, null=True, on_delete=django.db.models.deletion.SET_NULL, related_name='promoted_from', to='issues.issue'),
+        ),
+        migrations.AddField(
+            model_name='commentthread',
+            name='resolved_by',
+            field=models.ForeignKey(blank=True, null=True, on_delete=django.db.models.deletion.SET_NULL, related_name='+', to=settings.AUTH_USER_MODEL),
+        ),
+        migrations.AddField(
+            model_name='comment',
+            name='thread',
+            field=models.ForeignKey(on_delete=django.db.models.deletion.CASCADE, related_name='comments', to='comments.commentthread'),
+        ),
+        migrations.AddConstraint(
+            model_name='commentthread',
+            constraint=models.CheckConstraint(condition=models.Q(models.Q(('feature__isnull', False), ('issue__isnull', True), ('kind', 'feature'), ('line_end__isnull', True), ('line_start__isnull', True), ('revision__isnull', True)), models.Q(('feature__isnull', False), ('issue__isnull', True), ('kind', 'line'), ('line_end__gte', models.F('line_start')), ('line_start__gte', 1), ('revision__isnull', False)), models.Q(('feature__isnull', True), ('issue__isnull', False), ('kind', 'issue'), ('line_end__isnull', True), ('line_start__isnull', True), ('revision__isnull', True)), _connector='OR'), name='thread_target'),
+        ),
+        migrations.AddConstraint(
+            model_name='commentthread',
+            constraint=models.UniqueConstraint(condition=models.Q(('kind', 'issue')), fields=('issue',), name='thread_one_per_issue'),
+        ),
+    ]

intent/comments/models.py

@@ -0,0 +1,130 @@
+from django.conf import settings
+from django.db import models
+from django.db.models import F, Q
+
+from intent.core.models import BaseModel
+from intent.features.models import Feature
+from intent.issues.models import Issue
+from intent.projects.models import Project
+
+
+class ThreadKind(models.TextChoices):
+    FEATURE = "feature", "Feature"
+    LINE = "line", "Lines of a feature description"
+    ISSUE = "issue", "Issue"
+    # Phase 4 adds whole-file and image-point threads.
+
+
+def _target_is_consistent():
+    no_lines = Q(revision__isnull=True, line_start__isnull=True, line_end__isnull=True)
+    feature = Q(kind=ThreadKind.FEATURE, feature__isnull=False, issue__isnull=True) & no_lines
+    line = Q(
+        kind=ThreadKind.LINE,
+        feature__isnull=False,
+        issue__isnull=True,
+        revision__isnull=False,
+        line_start__gte=1,
+        line_end__gte=F("line_start"),
+    )
+    issue = Q(kind=ThreadKind.ISSUE, issue__isnull=False, feature__isnull=True) & no_lines
+    return feature | line | issue
+
+
+class CommentThread(BaseModel):
+    """A conversation attached to a feature, some lines of its description, or an issue.
+
+    An issue has exactly one thread: its discussion. Features can have many.
+    """
+
+    project = models.ForeignKey(Project, on_delete=models.CASCADE, related_name="threads")
+    kind = models.CharField(max_length=20, choices=ThreadKind.choices)
+    feature = models.ForeignKey(
+        Feature, null=True, blank=True, on_delete=models.CASCADE, related_name="threads"
+    )
+    issue = models.ForeignKey(
+        Issue, null=True, blank=True, on_delete=models.CASCADE, related_name="threads"
+    )
+    # Line threads: the feature revision the lines refer to, and the 1-based inclusive range.
+    revision = models.PositiveIntegerField(null=True, blank=True)
+    line_start = models.PositiveIntegerField(null=True, blank=True)
+    line_end = models.PositiveIntegerField(null=True, blank=True)
+    author = models.ForeignKey(
+        settings.AUTH_USER_MODEL, null=True, on_delete=models.SET_NULL, related_name="+"
+    )
+    resolved_at = models.DateTimeField(null=True, blank=True)
+    resolved_by = models.ForeignKey(
+        settings.AUTH_USER_MODEL,
+        null=True,
+        blank=True,
+        on_delete=models.SET_NULL,
+        related_name="+",
+    )
+    promoted_to = models.OneToOneField(
+        Issue,
+        null=True,
+        blank=True,
+        on_delete=models.SET_NULL,
+        related_name="promoted_from",
+    )
+
+    class Meta:
+        constraints = [
+            models.CheckConstraint(condition=_target_is_consistent(), name="thread_target"),
+            models.UniqueConstraint(
+                fields=["issue"],
+                condition=Q(kind=ThreadKind.ISSUE),
+                name="thread_one_per_issue",
+            ),
+        ]
+        ordering = ["created_at", "id"]
+
+    def __str__(self):
+        target = self.issue.key if self.issue_id else self.feature.key
+        return f"{self.get_kind_display()} thread on {target}"
+
+    @property
+    def is_resolved(self) -> bool:
+        return self.resolved_at is not None
+
+    @property
+    def dom_id(self) -> str:
+        """The id of the element that HTMX swaps when this thread changes."""
+        return "timeline" if self.kind == ThreadKind.ISSUE else f"thread-{self.pk}"
+
+
+class Comment(BaseModel):
+    thread = models.ForeignKey(CommentThread, on_delete=models.CASCADE, related_name="comments")
+    author = models.ForeignKey(
+        settings.AUTH_USER_MODEL, null=True, on_delete=models.SET_NULL, related_name="+"
+    )
+    body = models.TextField(blank=True)
+    edited_at = models.DateTimeField(null=True, blank=True)
+    # Deleted comments stay as tombstones so the thread still reads in order.
+    deleted_at = models.DateTimeField(null=True, blank=True)
+    deleted_by = models.ForeignKey(
+        settings.AUTH_USER_MODEL,
+        null=True,
+        blank=True,
+        on_delete=models.SET_NULL,
+        related_name="+",
+    )
+
+    class Meta:
+        ordering = ["created_at", "id"]
+
+    def __str__(self):
+        return f"Comment by {self.author} on {self.thread}"
+
+    @property
+    def is_deleted(self) -> bool:
+        return self.deleted_at is not None
+
+
+class CommentEdit(BaseModel):
+    """A comment's text before an edit. `created_at` is when it was replaced."""
+
+    comment = models.ForeignKey(Comment, on_delete=models.CASCADE, related_name="edits")
+    body = models.TextField()
+
+    class Meta:
+        ordering = ["created_at", "id"]

intent/comments/presenters.py

@@ -0,0 +1,84 @@
+"""Prepare threads for templates: rendered comment text, per-object permissions, line state."""
+
+from django.db.models import Prefetch
+from django.urls import reverse
+
+from intent.access import (
+    can_delete_comment,
+    can_edit_comment,
+    can_promote_thread,
+    can_resolve_thread,
+)
+from intent.markdown import render, render_blocks, source_lines
+
+from .models import Comment, ThreadKind
+
+
+def prepare_threads(threads, user, access) -> list:
+    """Load threads with their comments, and attach what the templates need to each."""
+    threads = list(
+        threads.select_related(
+            "project__org", "feature__project", "issue", "author", "resolved_by", "promoted_to"
+        ).prefetch_related(Prefetch("comments", queryset=Comment.objects.select_related("author")))
+    )
+    for thread in threads:
+        thread.can_resolve = can_resolve_thread(user, access, thread)
+        thread.can_promote = can_promote_thread(user, access, thread)
+        thread.comment_list = list(thread.comments.all())
+        thread.live_count = sum(1 for c in thread.comment_list if not c.is_deleted)
+        for comment in thread.comment_list:
+            comment.html = "" if comment.is_deleted else render(comment.body, heading_base=3)
+            comment.can_edit = can_edit_comment(user, access, comment)
+            comment.can_delete = can_delete_comment(user, access, comment)
+    return threads
+
+
+def mark_line_threads(feature, threads) -> None:
+    """Decide which line threads still point at the current text.
+
+    A thread is current if the description is unchanged since its revision (a status change
+    alone doesn't outdate it). Outdated threads keep a quote of the lines they were about.
+    """
+    line_threads = [t for t in threads if t.kind == ThreadKind.LINE]
+    revisions = {t.revision for t in line_threads}
+    texts = dict(
+        feature.revisions.filter(revision__in=revisions).values_list("revision", "description")
+    )
+    for thread in line_threads:
+        old = texts.get(thread.revision, "")
+        thread.outdated = old != feature.description
+        thread.quoted = source_lines(old, thread.line_start, thread.line_end)
+
+
+def feature_discussion(feature, user, access) -> dict:
+    """Context for a feature page: description blocks with their line threads, and the rest."""
+    threads = prepare_threads(feature.threads.all(), user, access)
+    mark_line_threads(feature, threads)
+    blocks = render_blocks(feature.description)
+    by_range = {(b.start, b.end): [] for b in blocks}
+    outdated = []
+    for thread in threads:
+        if thread.kind != ThreadKind.LINE:
+            continue
+        key = (thread.line_start, thread.line_end)
+        if not thread.outdated and key in by_range:
+            by_range[key].append(thread)
+        else:
+            thread.outdated = True
+            outdated.append(thread)
+    return {
+        "blocks": [(block, by_range[(block.start, block.end)]) for block in blocks],
+        "general_threads": [t for t in threads if t.kind == ThreadKind.FEATURE],
+        "outdated_threads": outdated,
+    }
+
+
+def thread_url(thread, anchor=None) -> str:
+    """Where a thread lives: its feature's page, or its issue's page."""
+    project = thread.project
+    kwargs = {"org_slug": project.org.slug, "project_slug": project.slug}
+    if thread.kind == ThreadKind.ISSUE:
+        url = reverse("issues:detail", kwargs={**kwargs, "number": thread.issue.number})
+    else:
+        url = reverse("features:detail", kwargs={**kwargs, "feature_key": thread.feature.key})
+    return f"{url}#{anchor or thread.dom_id}"

intent/comments/services.py

@@ -0,0 +1,98 @@
+"""Comment thread rules. Same conventions as intent.orgs.services."""
+
+from django.core.exceptions import PermissionDenied, ValidationError
+from django.db import transaction
+from django.utils import timezone
+
+from intent.access import (
+    can_delete_comment,
+    can_edit_comment,
+    can_resolve_thread,
+    project_access,
+)
+
+from .models import Comment, CommentEdit, CommentThread, ThreadKind
+
+MAX_BODY = 20_000
+STALE_MESSAGE = (
+    "The description changed while you were writing, so those lines may have moved. "
+    "Your comment wasn't posted; choose the lines again."
+)
+
+
+def clean_body(body: str) -> str:
+    body = (body or "").strip()
+    if not body:
+        raise ValidationError("Write a comment first.")
+    if len(body) > MAX_BODY:
+        raise ValidationError(f"Keep comments under {MAX_BODY:,} characters.")
+    return body
+
+
+def _require_contribute(by, project):
+    if not project_access(by, project).can_contribute:
+        raise PermissionDenied
+
+
+def start_feature_thread(
+    feature, by, *, body, revision=None, line_start=None, line_end=None
+) -> CommentThread:
+    """Start a thread on a feature, or on lines of its current description."""
+    _require_contribute(by, feature.project)
+    body = clean_body(body)
+    fields = {"project": feature.project, "feature": feature, "author": by}
+    if line_start is None:
+        fields["kind"] = ThreadKind.FEATURE
+    else:
+        if revision != feature.current_revision:
+            raise ValidationError(STALE_MESSAGE)
+        line_count = len(feature.description.splitlines())
+        if not (1 <= line_start <= (line_end or 0) <= line_count):
+            raise ValidationError("Those lines aren't in the description.")
+        fields.update(
+            kind=ThreadKind.LINE, revision=revision, line_start=line_start, line_end=line_end
+        )
+    with transaction.atomic():
+        thread = CommentThread.objects.create(**fields)
+        Comment.objects.create(thread=thread, author=by, body=body)
+    return thread
+
+
+def reply(thread, by, *, body) -> Comment:
+    _require_contribute(by, thread.project)
+    return Comment.objects.create(thread=thread, author=by, body=clean_body(body))
+
+
+def edit_comment(comment, by, *, body) -> None:
+    if not can_edit_comment(by, project_access(by, comment.thread.project), comment):
+        raise PermissionDenied
+    body = clean_body(body)
+    if body == comment.body:
+        raise ValidationError("Nothing changed.")
+    with transaction.atomic():
+        CommentEdit.objects.create(comment=comment, body=comment.body)
+        comment.body = body
+        comment.edited_at = timezone.now()
+        comment.save(update_fields=["body", "edited_at", "updated_at"])
+
+
+def delete_comment(comment, by) -> None:
+    """Leave a tombstone: the text and its edit history are removed."""
+    if not can_delete_comment(by, project_access(by, comment.thread.project), comment):
+        raise PermissionDenied
+    with transaction.atomic():
+        comment.edits.all().delete()
+        comment.body = ""
+        comment.deleted_at = timezone.now()
+        comment.deleted_by = by
+        comment.save(update_fields=["body", "deleted_at", "deleted_by", "updated_at"])
+
+
+def set_resolved(thread, by, resolved: bool) -> None:
+    if not can_resolve_thread(by, project_access(by, thread.project), thread):
+        raise PermissionDenied
+    if resolved == thread.is_resolved:
+        return
+    thread.resolved_at = timezone.now() if resolved else None
+    thread.resolved_by = by if resolved else None
+    thread.save(update_fields=["resolved_at", "resolved_by", "updated_at"])

intent/comments/urls.py

@@ -0,0 +1,14 @@
+from django.urls import path
+
+from . import views
+
+app_name = "comments"
+
+urlpatterns = [
+    path("threads/<str:thread_id>/reply/", views.thread_reply, name="reply"),
+    path("threads/<str:thread_id>/resolve/", views.thread_resolve, name="resolve"),
+    path("threads/<str:thread_id>/promote/", views.thread_promote, name="promote"),
+    path("comments/<str:comment_id>/edit/", views.comment_edit, name="edit"),
+    path("comments/<str:comment_id>/delete/", views.comment_delete, name="delete"),
+    path("comments/<str:comment_id>/history/", views.comment_history, name="history"),
+]

intent/comments/views.py

@@ -0,0 +1,197 @@
+"""Thread and comment actions.
+
+Every action is a plain form POST that redirects back to the thread. When HTMX sends it
+(`HX-Request`), the response is instead the re-rendered thread, swapped in place.
+"""
+
+from django.contrib import messages
+from django.core.exceptions import PermissionDenied, ValidationError
+from django.shortcuts import get_object_or_404, redirect, render
+from django.urls import reverse
+from django.views.decorators.http import require_POST
+
+from intent.access import can_promote_thread
+from intent.features.views import get_feature
+from intent.issues import services as issue_services
+from intent.projects.decorators import project_view
+
+from . import services
+from .forms import CommentForm, LineThreadForm, PromoteForm
+from .models import Comment, CommentThread, ThreadKind
+from .presenters import mark_line_threads, prepare_threads, thread_url
+
+
+def _is_htmx(request) -> bool:
+    return request.headers.get("HX-Request") == "true"
+
+
+def _get_thread(project, thread_id) -> CommentThread:
+    return get_object_or_404(
+        CommentThread.objects.select_related("project__org", "feature__project", "issue"),
+        project=project,
+        pk=thread_id,
+    )
+
+
+def _get_comment(project, comment_id) -> Comment:
+    return get_object_or_404(
+        Comment.objects.select_related(
+            "author", "thread__project__org", "thread__feature__project", "thread__issue"
+        ),
+        thread__project=project,
+        pk=comment_id,
+    )
+
+
+def render_thread(request, project, access, thread, *, focus=None, error=None, draft=""):
+    """The HTMX fragment for a thread: an issue's timeline, or a single feature thread."""
+    context = {"project": project, "access": access, "focus": focus, "error": error}
+    if thread.kind == ThreadKind.ISSUE:
+        from intent.issues.views import timeline_context
+
+        context.update(timeline_context(thread.issue, request.user, access))
+        context["draft"] = draft
+        return render(request, "issues/_timeline.html", context)
+    (prepared,) = prepare_threads(CommentThread.objects.filter(pk=thread.pk), request.user, access)
+    if prepared.kind == ThreadKind.LINE:
+        mark_line_threads(prepared.feature, [prepared])
+    prepared.draft = draft
+    context["thread"] = prepared
+    return render(request, "comments/_thread.html", context)
+
+
+def _done(request, project, access, thread, *, focus=None):
+    if _is_htmx(request):
+        return render_thread(request, project, access, thread, focus=focus)
+    return redirect(thread_url(thread, focus))
+
+
+def _failed(request, project, access, thread, exc, draft="", back=None):
+    """Show what went wrong without losing what the person wrote."""
+    error = " ".join(exc.messages)
+    if _is_htmx(request) and thread is not None:
+        return render_thread(request, project, access, thread, error=error, draft=draft)
+    back = back or thread_url(thread)
+    context = {"project": project, "access": access, "error": error, "draft": draft, "back": back}
+    return render(request, "comments/not_posted.html", context, status=400)
+
+
+def _form_error(form) -> ValidationError:
+    return ValidationError([e for errors in form.errors.values() for e in errors])
+
+
+@project_view(require="can_contribute")
+@require_POST
+def feature_thread_create(request, project, access, feature_key):
+    feature = get_feature(project, feature_key)
+    on_lines = "line_start" in request.POST
+    form = (LineThreadForm if on_lines else CommentForm)(request.POST)
+    draft = request.POST.get("body", "")
+    if not form.is_valid():
+        exc = _form_error(form)
+    else:
+        data = form.cleaned_data
+        lines = {k: data[k] for k in ("revision", "line_start", "line_end")} if on_lines else {}
+        try:
+            thread = services.start_feature_thread(
+                feature, request.user, body=data["body"], **lines
+            )
+        except ValidationError as error:
+            exc = error
+        else:
+            return redirect(thread_url(thread))
+    back = reverse(
+        "features:detail",
+        kwargs={
+            "org_slug": project.org.slug,
+            "project_slug": project.slug,
+            "feature_key": feature.key,
+        },
+    )
+    return _failed(request, project, access, None, exc, draft, back=back)
+
+
+@project_view(require="can_contribute")
+@require_POST
+def thread_reply(request, project, access, thread_id):
+    thread = _get_thread(project, thread_id)
+    try:
+        comment = services.reply(thread, request.user, body=request.POST.get("body", ""))
+    except ValidationError as exc:
+        return _failed(request, project, access, thread, exc, request.POST.get("body", ""))
+    return _done(request, project, access, thread, focus=f"comment-{comment.pk}")
+
+
+@project_view()
+@require_POST
+def thread_resolve(request, project, access, thread_id):
+    thread = _get_thread(project, thread_id)
+    services.set_resolved(thread, request.user, request.POST.get("resolved") == "1")
+    return _done(request, project, access, thread, focus=thread.dom_id)
+
+
+@project_view(require="can_contribute")
+def thread_promote(request, project, access, thread_id):
+    thread = _get_thread(project, thread_id)
+    if request.method == "POST":
+        form = PromoteForm(request.POST)
+        if form.is_valid():
+            try:
+                issue = issue_services.promote_thread(thread, request.user, **form.cleaned_data)
+            except ValidationError as exc:
+                form.add_error(None, exc)
+            else:
+                messages.success(request, f"Opened {issue.key} from the thread.")
+                return redirect(
+                    "issues:detail",
+                    org_slug=project.org.slug,
+                    project_slug=project.slug,
+                    number=issue.number,
+                )
+    else:
+        # Check up front, so people without the right don't fill in the form for nothing.
+        if not can_promote_thread(request.user, access, thread):
+            raise PermissionDenied
+        title, body = issue_services.promotion_text(thread)
+        form = PromoteForm(initial={"title": title, "body": body})
+    context = {
+        "project": project,
+        "access": access,
+        "thread": thread,
+        "form": form,
+        "back": thread_url(thread),
+    }
+    return render(request, "comments/promote.html", context)
+
+
+@project_view()
+@require_POST
+def comment_edit(request, project, access, comment_id):
+    comment = _get_comment(project, comment_id)
+    try:
+        services.edit_comment(comment, request.user, body=request.POST.get("body", ""))
+    except ValidationError as exc:
+        return _failed(request, project, access, comment.thread, exc, request.POST.get("body", ""))
+    return _done(request, project, access, comment.thread, focus=f"comment-{comment.pk}")
+
+
+@project_view()
+@require_POST
+def comment_delete(request, project, access, comment_id):
+    comment = _get_comment(project, comment_id)
+    services.delete_comment(comment, request.user)
+    return _done(request, project, access, comment.thread, focus=f"comment-{comment.pk}")
+
+
+@project_view()
+def comment_history(request, project, access, comment_id):
+    comment = _get_comment(project, comment_id)
+    versions = list(comment.edits.all())
+    context = {
+        "project": project,
+        "access": access,
+        "comment": comment,
+        "versions": versions,
+        "back": thread_url(comment.thread, f"comment-{comment.pk}"),
+    }
+    return render(request, "comments/history.html", context)

intent/features/forms.py

@@ -31,8 +31,12 @@ class FeatureForm(forms.Form):
         help_text="Why is this changing? Kept in the feature's history.",
     )
 
-    def __init__(self, *args, project, feature=None, exclude_ids=(), **kwargs):
+    def __init__(self, *args, project, feature=None, exclude_ids=(), issue=None, **kwargs):
         super().__init__(*args, **kwargs)
+        if issue is not None and issue.is_open:
+            self.fields["accept_issue"] = forms.BooleanField(
+                required=False, initial=True, label=f"Mark issue {issue.key} accepted"
+            )
         others = project.features.select_related("project")
         if feature:
             others = others.exclude(pk=feature.pk)

intent/features/services.py

@@ -9,6 +9,8 @@ from intent.projects.models import Project
 
 from .models import Feature, FeatureRevision, FeatureStatus
 
+# Imported late in functions: intent.issues depends on this app's models.
+
 TRACKED_FIELDS = ["title", "description", "parent_id", "status", "superseded_by_id"]
 
 
@@ -76,7 +78,20 @@ def _record(feature, by, note) -> FeatureRevision:
     )
 
 
-def create_feature(project, by, *, title, description="", parent=None, note="") -> Feature:
+def _tie_to_issues(revision, by, issues, accept) -> None:
+    """Link a revision to the issues it was made for, accepting any that are still open."""
+    from intent.issues import services as issue_services
+    from intent.issues.models import IssueStatus
+
+    for issue in issues:
+        issue_services.record_revision(issue, by, revision)
+        if accept and issue.is_open:
+            issue_services.set_status(issue, by, IssueStatus.ACCEPTED)
+
+
+def create_feature(
+    project, by, *, title, description="", parent=None, note="", issues=(), accept_issues=False
+) -> Feature:
     _require_edit(by, project)
     with transaction.atomic():
         Project.objects.filter(pk=project.pk).update(
@@ -93,12 +108,18 @@ def create_feature(project, by, *, title, description="", parent=None, note="")
         )
         _validate(feature)
         feature.save()
-        _record(feature, by, note.strip() or "Created.")
+        revision = _record(feature, by, note.strip() or "Created.")
+        _tie_to_issues(revision, by, issues, accept_issues)
     return feature
 
 
-def update_feature(feature, by, *, note, **changes) -> FeatureRevision:
+def update_feature(
-    """Apply changes to tracked fields and record a revision. `note` explains why."""
+    feature, by, *, note, issues=(), accept_issues=False, **changes
+) -> FeatureRevision:
+    """Apply changes to tracked fields and record a revision. `note` explains why.
+
+    `issues` are the issues this change was made for; `accept_issues` accepts the open ones.
+    """
     _require_edit(by, feature.project)
     note = note.strip()
     if not note:
@@ -113,4 +134,6 @@ def update_feature(feature, by, *, note, **changes) -> FeatureRevision:
             raise ValidationError("Nothing changed.")
         feature.current_revision += 1
         feature.save()
-        return _record(feature, by, note)
+        revision = _record(feature, by, note)
+        _tie_to_issues(revision, by, issues, accept_issues)
+        return revision

intent/features/urls.py

@@ -1,5 +1,7 @@
 from django.urls import path
 
+from intent.comments import views as comment_views
+
 from . import views
 
 app_name = "features"
@@ -12,4 +14,9 @@ urlpatterns = [
     path("<str:feature_key>/history/", views.feature_history, name="history"),
     path("<str:feature_key>/history/<int:revision>/", views.feature_revision, name="revision"),
     path("<str:feature_key>/compare/", views.feature_compare, name="compare"),
+    path(
+        "<str:feature_key>/threads/",
+        comment_views.feature_thread_create,
+        name="thread_create",
+    ),
 ]

intent/features/views.py

@@ -1,9 +1,12 @@
 from django.contrib import messages
 from django.core.exceptions import ValidationError
+from django.db.models import Prefetch
 from django.http import Http404
 from django.shortcuts import get_object_or_404, redirect, render
 
+from intent.comments.presenters import feature_discussion
 from intent.markdown import render as render_markdown
+from intent.markdown import render_blocks
 from intent.projects.decorators import project_view
 
 from . import services
@@ -23,6 +26,16 @@ def get_feature(project, feature_key) -> Feature:
     )
 
 
+def _issue_from_query(request, project):
+    """The issue a feature change is being made for, from `?issue=N`."""
+    from intent.issues.models import Issue
+
+    number = request.GET.get("issue", "")
+    if not number.isdigit():
+        return None
+    return get_object_or_404(Issue, project=project, number=int(number))
+
+
 def _feature_redirect(feature, name="detail"):
     return redirect(
         f"features:{name}",
@@ -47,7 +60,10 @@ def feature_create(request, project, access):
     initial = {}
     if parent_key := request.GET.get("parent"):
         initial["parent"] = get_feature(project, parent_key)
-    form = FeatureForm(request.POST or None, project=project, initial=initial)
+    issue = _issue_from_query(request, project)
+    if issue:
+        initial.update(title=issue.title, description=issue.body, note=f"Created for {issue.key}.")
+    form = FeatureForm(request.POST or None, project=project, initial=initial, issue=issue)
     preview = None
     if request.method == "POST" and form.is_valid():
         data = form.cleaned_data
@@ -62,13 +78,21 @@ def feature_create(request, project, access):
                     description=data["description"],
                     parent=data["parent"],
                     note=data["note"],
+                    issues=[issue] if issue else [],
+                    accept_issues=data.get("accept_issue", False),
                 )
             except ValidationError as exc:
                 form.add_error(None, exc)
             else:
                 messages.success(request, f"Created {feature.key}.")
                 return _feature_redirect(feature)
-    context = {"project": project, "access": access, "form": form, "preview": preview}
+    context = {
+        "project": project,
+        "access": access,
+        "form": form,
+        "preview": preview,
+        "issue": issue,
+    }
     return render(request, "features/form.html", context)
 
 
@@ -84,7 +108,8 @@ def feature_detail(request, project, access, feature_key):
         "ancestors": _ancestors(feature),
         "children": feature.children.select_related("project"),
         "supersedes": feature.supersedes.select_related("project"),
-        "description": render_markdown(feature.description),
+        "issues": feature.issues.select_related("project"),
+        **feature_discussion(feature, request.user, access),
     }
     return render(request, "features/detail.html", context)
 
@@ -100,6 +125,7 @@ def _ancestors(feature) -> list[Feature]:
 @project_view(require="can_edit")
 def feature_edit(request, project, access, feature_key):
     feature = get_feature(project, feature_key)
+    issue = _issue_from_query(request, project)
     initial = {
         "title": feature.title,
         "description": feature.description,
@@ -107,12 +133,15 @@ def feature_edit(request, project, access, feature_key):
         "status": feature.status,
         "superseded_by": feature.superseded_by,
     }
+    if issue:
+        initial["note"] = f"{issue.key}: {issue.title}"[:500]
     form = FeatureForm(
         request.POST or None,
         project=project,
         feature=feature,
         exclude_ids=services.descendant_ids(feature),
         initial=initial,
+        issue=issue,
     )
     preview = None
     if request.method == "POST" and form.is_valid():
@@ -120,8 +149,15 @@ def feature_edit(request, project, access, feature_key):
         if "preview" in request.POST:
             preview = render_markdown(data["description"])
         else:
+            accept = data.pop("accept_issue", False)
             try:
-                services.update_feature(feature, request.user, **data)
+                services.update_feature(
+                    feature,
+                    request.user,
+                    issues=[issue] if issue else [],
+                    accept_issues=accept,
+                    **data,
+                )
             except ValidationError as exc:
                 form.add_error(None, exc)
             else:
@@ -133,6 +169,7 @@ def feature_edit(request, project, access, feature_key):
         "feature": feature,
         "form": form,
         "preview": preview,
+        "issue": issue,
     }
     return render(request, "features/form.html", context)
 
@@ -156,7 +193,13 @@ def _changes(revision, previous) -> list[str]:
 @project_view()
 def feature_history(request, project, access, feature_key):
     feature = get_feature(project, feature_key)
-    revisions = list(feature.revisions.select_related("author"))
+    from intent.issues.models import Issue
+
+    revisions = list(
+        feature.revisions.select_related("author").prefetch_related(
+            Prefetch("issues", queryset=Issue.objects.order_by("number"))
+        )
+    )
     rows = [
         {"revision": rev, "changes": _changes(rev, revisions[i - 1] if i else None)}
         for i, rev in enumerate(revisions)
@@ -180,7 +223,7 @@ def feature_revision(request, project, access, feature_key, revision):
         "access": access,
         "feature": feature,
         "snapshot": snapshot,
-        "description": render_markdown(snapshot.description),
+        "blocks": render_blocks(snapshot.description),
     }
     return render(request, "features/revision.html", context)
 

intent/issues/admin.py

@@ -0,0 +1,31 @@
+from django.contrib import admin
+
+from .models import Issue, IssueEvent
+
+
+class IssueEventInline(admin.TabularInline):
+    model = IssueEvent
+    fk_name = "issue"
+    extra = 0
+    can_delete = False
+    fields = ["created_at", "actor", "kind", "status", "feature", "revision"]
+    readonly_fields = fields
+
+    def has_add_permission(self, request, obj=None):
+        return False
+
+
+@admin.register(Issue)
+class IssueAdmin(admin.ModelAdmin):
+    """Read-only: changes go through the app so they're recorded in the timeline."""
+
+    list_display = ["__str__", "project", "status", "author", "created_at"]
+    list_filter = ["status"]
+    search_fields = ["title"]
+    inlines = [IssueEventInline]
+
+    def has_add_permission(self, request):
+        return False
+
+    def has_change_permission(self, request, obj=None):
+        return False

intent/issues/apps.py

@@ -0,0 +1,6 @@
+from django.apps import AppConfig
+
+
+class IssuesConfig(AppConfig):
+    name = "intent.issues"
+    label = "issues"

intent/issues/forms.py

@@ -0,0 +1,58 @@
+from django import forms
+
+from intent.features.forms import FeatureChoiceField
+
+from .models import Issue
+
+
+class FeatureMultipleChoiceField(forms.ModelMultipleChoiceField):
+    def label_from_instance(self, obj):
+        return f"{obj.key} {obj.title}"
+
+
+class IssueForm(forms.Form):
+    title = forms.CharField(max_length=200)
+    body = forms.CharField(
+        label="Description",
+        required=False,
+        widget=forms.Textarea(attrs={"rows": 12, "cols": 80}),
+        help_text="Markdown. What's the problem, or what would you like to change?",
+    )
+    features = FeatureMultipleChoiceField(
+        queryset=None,
+        required=False,
+        label="Related features",
+        help_text="Optional. Hold Ctrl or ⌘ to choose more than one.",
+    )
+
+    def __init__(self, *args, project, include_features=True, **kwargs):
+        super().__init__(*args, **kwargs)
+        if include_features:
+            self.fields["features"].queryset = project.features.select_related("project")
+        else:
+            del self.fields["features"]
+
+
+class DuplicateForm(forms.Form):
+    number = forms.IntegerField(min_value=1, label="Duplicate of issue number")
+
+    def __init__(self, *args, project, **kwargs):
+        super().__init__(*args, **kwargs)
+        self.project = project
+
+    def clean_number(self):
+        number = self.cleaned_data["number"]
+        original = Issue.objects.filter(project=self.project, number=number).first()
+        if original is None:
+            raise forms.ValidationError(f"There's no issue #{number} in this project.")
+        return original
+
+
+class LinkFeatureForm(forms.Form):
+    feature = FeatureChoiceField(queryset=None, label="Feature")
+
+    def __init__(self, *args, issue, **kwargs):
+        super().__init__(*args, **kwargs)
+        self.fields["feature"].queryset = issue.project.features.select_related("project").exclude(
+            issues=issue
+        )

intent/issues/migrations/0001_initial.py

@@ -0,0 +1,70 @@
+# Generated by Django 5.2.18 on 2026-10-27 12:49
+
+import django.db.models.deletion
+import intent.core.models
+from django.conf import settings
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    initial = True
+
+    dependencies = [
+        ('features', '0002_initial'),
+        ('projects', '0001_initial'),
+        migrations.swappable_dependency(settings.AUTH_USER_MODEL),
+    ]
+
+    operations = [
+        migrations.CreateModel(
+            name='Issue',
+            fields=[
+                ('id', intent.core.models.ULIDField(default=intent.core.models.new_ulid, editable=False, max_length=26, primary_key=True, serialize=False)),
+                ('created_at', models.DateTimeField(auto_now_add=True)),
+                ('updated_at', models.DateTimeField(auto_now=True)),
+                ('number', models.PositiveIntegerField()),
+                ('title', models.CharField(max_length=200)),
+                ('body', models.TextField(blank=True)),
+                ('status', models.CharField(choices=[('open', 'Open'), ('accepted', 'Accepted'), ('rejected', 'Rejected'), ('withdrawn', 'Withdrawn'), ('duplicate', 'Duplicate')], default='open', max_length=20)),
+                ('closed_at', models.DateTimeField(blank=True, null=True)),
+                ('author', models.ForeignKey(null=True, on_delete=django.db.models.deletion.SET_NULL, related_name='+', to=settings.AUTH_USER_MODEL)),
+                ('duplicate_of', models.ForeignKey(blank=True, null=True, on_delete=django.db.models.deletion.RESTRICT, related_name='duplicates', to='issues.issue')),
+                ('features', models.ManyToManyField(blank=True, related_name='issues', to='features.feature')),
+                ('project', models.ForeignKey(on_delete=django.db.models.deletion.CASCADE, related_name='issues', to='projects.project')),
+                ('revisions', models.ManyToManyField(blank=True, related_name='issues', to='features.featurerevision')),
+            ],
+            options={
+                'ordering': ['-number'],
+            },
+        ),
+        migrations.CreateModel(
+            name='IssueEvent',
+            fields=[
+                ('id', intent.core.models.ULIDField(default=intent.core.models.new_ulid, editable=False, max_length=26, primary_key=True, serialize=False)),
+                ('created_at', models.DateTimeField(auto_now_add=True)),
+                ('updated_at', models.DateTimeField(auto_now=True)),
+                ('kind', models.CharField(choices=[('status', 'Status changed'), ('linked', 'Feature linked'), ('unlinked', 'Feature unlinked'), ('revision', 'Feature revised'), ('edited', 'Edited')], max_length=20)),
+                ('status', models.CharField(blank=True, choices=[('open', 'Open'), ('accepted', 'Accepted'), ('rejected', 'Rejected'), ('withdrawn', 'Withdrawn'), ('duplicate', 'Duplicate')], max_length=20)),
+                ('previous_status', models.CharField(blank=True, choices=[('open', 'Open'), ('accepted', 'Accepted'), ('rejected', 'Rejected'), ('withdrawn', 'Withdrawn'), ('duplicate', 'Duplicate')], max_length=20)),
+                ('old_title', models.CharField(blank=True, max_length=200)),
+                ('old_body', models.TextField(blank=True)),
+                ('actor', models.ForeignKey(null=True, on_delete=django.db.models.deletion.SET_NULL, related_name='+', to=settings.AUTH_USER_MODEL)),
+                ('duplicate_of', models.ForeignKey(blank=True, null=True, on_delete=django.db.models.deletion.SET_NULL, related_name='+', to='issues.issue')),
+                ('feature', models.ForeignKey(blank=True, null=True, on_delete=django.db.models.deletion.SET_NULL, related_name='+', to='features.feature')),
+                ('issue', models.ForeignKey(on_delete=django.db.models.deletion.CASCADE, related_name='events', to='issues.issue')),
+                ('revision', models.ForeignKey(blank=True, null=True, on_delete=django.db.models.deletion.SET_NULL, related_name='+', to='features.featurerevision')),
+            ],
+            options={
+                'ordering': ['created_at', 'id'],
+            },
+        ),
+        migrations.AddConstraint(
+            model_name='issue',
+            constraint=models.UniqueConstraint(fields=('project', 'number'), name='issue_unique_number'),
+        ),
+        migrations.AddConstraint(
+            model_name='issue',
+            constraint=models.CheckConstraint(condition=models.Q(models.Q(('status', 'duplicate'), ('duplicate_of__isnull', False)), models.Q(models.Q(('status', 'duplicate'), _negated=True), models.Q(('duplicate_of__isnull', False), _negated=True)), _connector='OR'), name='issue_duplicate_of'),
+        ),
+    ]

intent/issues/models.py

@@ -0,0 +1,100 @@
+from django.conf import settings
+from django.db import models
+from django.db.models import Q
+
+from intent.core.models import BaseModel
+from intent.features.models import Feature, FeatureRevision
+from intent.projects.models import Project
+
+
+class IssueStatus(models.TextChoices):
+    OPEN = "open", "Open"
+    ACCEPTED = "accepted", "Accepted"
+    REJECTED = "rejected", "Rejected"
+    WITHDRAWN = "withdrawn", "Withdrawn"
+    DUPLICATE = "duplicate", "Duplicate"
+
+
+def _duplicate_needs_original():
+    is_duplicate = Q(status=IssueStatus.DUPLICATE)
+    has_original = Q(duplicate_of__isnull=False)
+    return (is_duplicate & has_original) | (~is_duplicate & ~has_original)
+
+
+class Issue(BaseModel):
+    """A problem or proposal. Discussed in its own comment thread, then decided."""
+
+    project = models.ForeignKey(Project, on_delete=models.CASCADE, related_name="issues")
+    number = models.PositiveIntegerField()
+    title = models.CharField(max_length=200)
+    body = models.TextField(blank=True)
+    author = models.ForeignKey(
+        settings.AUTH_USER_MODEL, null=True, on_delete=models.SET_NULL, related_name="+"
+    )
+    status = models.CharField(max_length=20, choices=IssueStatus.choices, default=IssueStatus.OPEN)
+    # RESTRICT (not PROTECT) so deleting a whole project can still cascade.
+    duplicate_of = models.ForeignKey(
+        "self", null=True, blank=True, on_delete=models.RESTRICT, related_name="duplicates"
+    )
+    closed_at = models.DateTimeField(null=True, blank=True)
+    features = models.ManyToManyField(Feature, blank=True, related_name="issues")
+    # Feature revisions made because of this issue ("edits can be tied to an issue").
+    revisions = models.ManyToManyField(FeatureRevision, blank=True, related_name="issues")
+
+    class Meta:
+        constraints = [
+            models.UniqueConstraint(fields=["project", "number"], name="issue_unique_number"),
+            models.CheckConstraint(
+                condition=_duplicate_needs_original(), name="issue_duplicate_of"
+            ),
+        ]
+        ordering = ["-number"]
+
+    def __str__(self):
+        return f"{self.key} {self.title}"
+
+    @property
+    def key(self) -> str:
+        return f"#{self.number}"
+
+    @property
+    def is_open(self) -> bool:
+        return self.status == IssueStatus.OPEN
+
+
+class EventKind(models.TextChoices):
+    STATUS = "status", "Status changed"
+    LINKED = "linked", "Feature linked"
+    UNLINKED = "unlinked", "Feature unlinked"
+    REVISION = "revision", "Feature revised"
+    EDITED = "edited", "Edited"
+
+
+class IssueEvent(BaseModel):
+    """Something that happened to an issue, shown in its timeline between comments."""
+
+    issue = models.ForeignKey(Issue, on_delete=models.CASCADE, related_name="events")
+    actor = models.ForeignKey(
+        settings.AUTH_USER_MODEL, null=True, on_delete=models.SET_NULL, related_name="+"
+    )
+    kind = models.CharField(max_length=20, choices=EventKind.choices)
+    status = models.CharField(max_length=20, choices=IssueStatus.choices, blank=True)
+    previous_status = models.CharField(max_length=20, choices=IssueStatus.choices, blank=True)
+    duplicate_of = models.ForeignKey(
+        Issue, null=True, blank=True, on_delete=models.SET_NULL, related_name="+"
+    )
+    feature = models.ForeignKey(
+        Feature, null=True, blank=True, on_delete=models.SET_NULL, related_name="+"
+    )
+    revision = models.ForeignKey(
+        FeatureRevision, null=True, blank=True, on_delete=models.SET_NULL, related_name="+"
+    )
+    # For edits: the text before the change.
+    old_title = models.CharField(max_length=200, blank=True)
+    old_body = models.TextField(blank=True)
+
+    class Meta:
+        ordering = ["created_at", "id"]
+
+    def __str__(self):
+        return f"{self.issue.key} {self.get_kind_display()}"

intent/issues/services.py

@@ -0,0 +1,193 @@
+"""Issue rules. Same conventions as intent.orgs.services."""
+
+from django.core.exceptions import PermissionDenied, ValidationError
+from django.db import transaction
+from django.db.models import F
+from django.utils import timezone
+
+from intent.access import (
+    can_edit_issue,
+    can_promote_thread,
+    can_withdraw_issue,
+    project_access,
+)
+from intent.comments.models import CommentThread, ThreadKind
+from intent.markdown import source_lines
+from intent.projects.models import Project
+
+from .models import EventKind, Issue, IssueEvent, IssueStatus
+
+MAX_BODY = 50_000
+
+
+def _clean_text(title, body):
+    title, body = title.strip(), body.strip()
+    if not title:
+        raise ValidationError("Give the issue a title.")
+    if len(body) > MAX_BODY:
+        raise ValidationError(f"Keep the description under {MAX_BODY:,} characters.")
+    return title, body
+
+
+def _check_features(project, features):
+    for feature in features:
+        if feature.project_id != project.pk:
+            raise ValidationError("Linked features must be in the same project.")
+
+
+def create_issue(project, by, *, title, body="", features=()) -> Issue:
+    if not project_access(by, project).can_contribute:
+        raise PermissionDenied
+    title, body = _clean_text(title, body)
+    _check_features(project, features)
+    with transaction.atomic():
+        Project.objects.filter(pk=project.pk).update(next_issue_number=F("next_issue_number") + 1)
+        project.refresh_from_db(fields=["next_issue_number"])
+        issue = Issue.objects.create(
+            project=project,
+            number=project.next_issue_number - 1,
+            title=title,
+            body=body,
+            author=by,
+        )
+        issue.features.set(features)
+        CommentThread.objects.create(project=project, kind=ThreadKind.ISSUE, issue=issue, author=by)
+    return issue
+
+
+def update_issue(issue, by, *, title, body) -> None:
+    if not can_edit_issue(by, project_access(by, issue.project), issue):
+        raise PermissionDenied
+    title, body = _clean_text(title, body)
+    if (title, body) == (issue.title, issue.body):
+        raise ValidationError("Nothing changed.")
+    with transaction.atomic():
+        IssueEvent.objects.create(
+            issue=issue,
+            actor=by,
+            kind=EventKind.EDITED,
+            old_title=issue.title,
+            old_body=issue.body,
+        )
+        issue.title, issue.body = title, body
+        issue.save(update_fields=["title", "body", "updated_at"])
+
+
+def _check_status_permission(issue, by, status) -> None:
+    access = project_access(by, issue.project)
+    if access.can_edit:
+        return
+    author = can_withdraw_issue(by, access, issue)
+    if status == IssueStatus.WITHDRAWN and author and issue.status == IssueStatus.OPEN:
+        return
+    if status == IssueStatus.OPEN and author and issue.status == IssueStatus.WITHDRAWN:
+        return
+    raise PermissionDenied
+
+
+def _check_duplicate_of(issue, original) -> None:
+    if original is None:
+        raise ValidationError("Say which issue this duplicates.")
+    if original.project_id != issue.project_id:
+        raise ValidationError("The original must be in the same project.")
+    node = original
+    while node is not None:
+        if node.pk == issue.pk:
+            raise ValidationError("An issue can't be a duplicate of itself or of its duplicates.")
+        node = node.duplicate_of
+
+
+def set_status(issue, by, status, *, duplicate_of=None) -> IssueEvent:
+    """Accept, reject, withdraw, mark duplicate, or reopen."""
+    _check_status_permission(issue, by, status)
+    with transaction.atomic():
+        issue.refresh_from_db()
+        if status == IssueStatus.DUPLICATE:
+            _check_duplicate_of(issue, duplicate_of)
+        else:
+            duplicate_of = None
+        if status == issue.status and duplicate_of == issue.duplicate_of:
+            raise ValidationError(f"{issue.key} is already {issue.get_status_display().lower()}.")
+        previous = issue.status
+        issue.status = status
+        issue.duplicate_of = duplicate_of
+        issue.closed_at = None if status == IssueStatus.OPEN else timezone.now()
+        issue.save(update_fields=["status", "duplicate_of", "closed_at", "updated_at"])
+        return IssueEvent.objects.create(
+            issue=issue,
+            actor=by,
+            kind=EventKind.STATUS,
+            status=status,
+            previous_status=previous,
+            duplicate_of=duplicate_of,
+        )
+
+
+def link_feature(issue, by, feature) -> None:
+    if not project_access(by, issue.project).can_edit:
+        raise PermissionDenied
+    _check_features(issue.project, [feature])
+    if issue.features.filter(pk=feature.pk).exists():
+        raise ValidationError(f"{feature.key} is already linked.")
+    with transaction.atomic():
+        issue.features.add(feature)
+        IssueEvent.objects.create(issue=issue, actor=by, kind=EventKind.LINKED, feature=feature)
+
+
+def unlink_feature(issue, by, feature) -> None:
+    if not project_access(by, issue.project).can_edit:
+        raise PermissionDenied
+    if not issue.features.filter(pk=feature.pk).exists():
+        raise ValidationError(f"{feature.key} isn't linked.")
+    with transaction.atomic():
+        issue.features.remove(feature)
+        IssueEvent.objects.create(issue=issue, actor=by, kind=EventKind.UNLINKED, feature=feature)
+
+
+def record_revision(issue, by, revision) -> None:
+    """Tie a feature revision to the issue it was made for. Called by the feature services."""
+    feature = revision.feature
+    if issue.project_id != feature.project_id:
+        raise ValidationError("The issue must be in the same project as the feature.")
+    issue.revisions.add(revision)
+    issue.features.add(feature)
+    IssueEvent.objects.create(
+        issue=issue, actor=by, kind=EventKind.REVISION, feature=feature, revision=revision
+    )
+
+
+def promotion_text(thread) -> tuple[str, str]:
+    """A suggested title and body for an issue made from a thread: the thread, quoted."""
+    comments = [c for c in thread.comments.select_related("author") if not c.is_deleted]
+    first = comments[0].body if comments else ""
+    title = (first.strip().splitlines() or [""])[0][:120]
+    where = thread.feature.key
+    if thread.kind == ThreadKind.LINE:
+        where += f", lines {thread.line_start}–{thread.line_end} of revision {thread.revision}"
+    parts = [f"From a comment thread on {where}."]
+    if thread.kind == ThreadKind.LINE:
+        snapshot = thread.feature.revisions.filter(revision=thread.revision).first()
+        if snapshot:
+            quoted = source_lines(snapshot.description, thread.line_start, thread.line_end)
+            parts.append("\n".join(f"> {line}".rstrip() for line in quoted.splitlines()))
+    for c in comments:
+        name = c.author.username if c.author else "deleted user"
+        quoted = "\n".join(f"> {line}".rstrip() for line in c.body.splitlines())
+        parts.append(f"**{name}** wrote:\n\n{quoted}")
+    return title, "\n\n".join(parts)
+
+
+def promote_thread(thread, by, *, title, body) -> Issue:
+    """Turn a feature thread into an issue linked to the feature, and resolve the thread."""
+    if not can_promote_thread(by, project_access(by, thread.project), thread):
+        raise PermissionDenied
+    with transaction.atomic():
+        thread = CommentThread.objects.select_for_update().get(pk=thread.pk)
+        if thread.promoted_to_id:
+            raise ValidationError("This thread is already an issue.")
+        issue = create_issue(thread.project, by, title=title, body=body, features=[thread.feature])
+        thread.promoted_to = issue
+        if not thread.resolved_at:
+            thread.resolved_at, thread.resolved_by = timezone.now(), by
+        thread.save(update_fields=["promoted_to", "resolved_at", "resolved_by", "updated_at"])
+    return issue

intent/issues/urls.py

@@ -0,0 +1,14 @@
+from django.urls import path
+
+from . import views
+
+app_name = "issues"
+
+urlpatterns = [
+    path("", views.issue_list, name="list"),
+    path("new/", views.issue_create, name="create"),
+    path("<int:number>/", views.issue_detail, name="detail"),
+    path("<int:number>/edit/", views.issue_edit, name="edit"),
+    path("<int:number>/status/", views.issue_status, name="status"),
+    path("<int:number>/features/", views.issue_features, name="features"),
+]

intent/issues/views.py

@@ -0,0 +1,210 @@
+from django.contrib import messages
+from django.core.exceptions import PermissionDenied, ValidationError
+from django.shortcuts import get_object_or_404, redirect, render
+from django.views.decorators.http import require_POST
+
+from intent.access import can_edit_issue, can_withdraw_issue
+from intent.comments.models import CommentThread, ThreadKind
+from intent.comments.presenters import prepare_threads, thread_url
+from intent.features.views import get_feature
+from intent.markdown import render as render_markdown
+from intent.projects.decorators import project_view
+
+from . import services
+from .forms import DuplicateForm, IssueForm, LinkFeatureForm
+from .models import Issue, IssueStatus
+
+FILTERS = {
+    "open": ("Open", {"status": IssueStatus.OPEN}),
+    "closed": ("Closed", {"status__in": [s for s in IssueStatus.values if s != "open"]}),
+    "all": ("All", {}),
+}
+
+
+def get_issue(project, number) -> Issue:
+    return get_object_or_404(
+        Issue.objects.select_related("project__org", "author", "duplicate_of"),
+        project=project,
+        number=number,
+    )
+
+
+def _issue_redirect(issue, anchor=""):
+    response = redirect(
+        "issues:detail",
+        org_slug=issue.project.org.slug,
+        project_slug=issue.project.slug,
+        number=issue.number,
+    )
+    if anchor:
+        response["Location"] += f"#{anchor}"
+    return response
+
+
+def _error(request, exc: ValidationError):
+    for message in exc.messages:
+        messages.error(request, message)
+
+
+def timeline_context(issue, user, access) -> dict:
+    """Comments and events in time order, for the issue page and its HTMX fragment."""
+    (thread,) = prepare_threads(
+        CommentThread.objects.filter(issue=issue, kind=ThreadKind.ISSUE), user, access
+    )
+    events = issue.events.select_related("actor", "duplicate_of", "feature__project", "revision")
+    for event in events:
+        if event.old_body:
+            event.old_html = render_markdown(event.old_body, heading_base=3)
+    items = [("comment", c) for c in thread.comment_list] + [("event", e) for e in events]
+    items.sort(key=lambda item: (item[1].created_at, item[1].pk))
+    return {"issue": issue, "thread": thread, "timeline": items}
+
+
+@project_view()
+def issue_list(request, project, access):
+    current = request.GET.get("status", "open")
+    if current not in FILTERS:
+        current = "open"
+    issues = (
+        project.issues.filter(**FILTERS[current][1])
+        .select_related("author", "project")
+        .prefetch_related("features__project")
+    )
+    context = {
+        "project": project,
+        "access": access,
+        "issues": issues,
+        "filters": [(key, label) for key, (label, _) in FILTERS.items()],
+        "current": current,
+    }
+    return render(request, "issues/list.html", context)
+
+
+@project_view(require="can_contribute")
+def issue_create(request, project, access):
+    initial = {}
+    if feature_key := request.GET.get("feature"):
+        initial["features"] = [get_feature(project, feature_key)]
+    form = IssueForm(request.POST or None, project=project, initial=initial)
+    preview = None
+    if request.method == "POST" and form.is_valid():
+        data = form.cleaned_data
+        if "preview" in request.POST:
+            preview = render_markdown(data["body"], heading_base=3)
+        else:
+            try:
+                issue = services.create_issue(project, request.user, **data)
+            except ValidationError as exc:
+                form.add_error(None, exc)
+            else:
+                messages.success(request, f"Opened {issue.key}.")
+                return _issue_redirect(issue)
+    context = {"project": project, "access": access, "form": form, "preview": preview}
+    return render(request, "issues/form.html", context)
+
+
+@project_view()
+def issue_detail(request, project, access, number):
+    issue = get_issue(project, number)
+    user = request.user
+    promoted_from = (
+        CommentThread.objects.filter(promoted_to=issue)
+        .select_related("project__org", "feature__project")
+        .first()
+    )
+    context = {
+        "project": project,
+        "access": access,
+        "body": render_markdown(issue.body),
+        "features": issue.features.select_related("project"),
+        "promoted_from": promoted_from,
+        "promoted_url": thread_url(promoted_from) if promoted_from else None,
+        "duplicates": issue.duplicates.all(),
+        "can_edit_issue": can_edit_issue(user, access, issue),
+        "can_withdraw": can_withdraw_issue(user, access, issue),
+        "duplicate_form": DuplicateForm(project=project),
+        "link_form": LinkFeatureForm(issue=issue) if access.can_edit else None,
+        **timeline_context(issue, user, access),
+    }
+    return render(request, "issues/detail.html", context)
+
+
+@project_view()
+def issue_edit(request, project, access, number):
+    issue = get_issue(project, number)
+    if not can_edit_issue(request.user, access, issue):
+        raise PermissionDenied
+    form = IssueForm(
+        request.POST or None,
+        project=project,
+        include_features=False,
+        initial={"title": issue.title, "body": issue.body},
+    )
+    preview = None
+    if request.method == "POST" and form.is_valid():
+        data = form.cleaned_data
+        if "preview" in request.POST:
+            preview = render_markdown(data["body"], heading_base=3)
+        else:
+            try:
+                services.update_issue(issue, request.user, **data)
+            except ValidationError as exc:
+                form.add_error(None, exc)
+            else:
+                messages.success(request, f"Saved {issue.key}.")
+                return _issue_redirect(issue)
+    context = {
+        "project": project,
+        "access": access,
+        "issue": issue,
+        "form": form,
+        "preview": preview,
+    }
+    return render(request, "issues/form.html", context)
+
+
+@project_view()
+@require_POST
+def issue_status(request, project, access, number):
+    issue = get_issue(project, number)
+    status = request.POST.get("status")
+    if status not in IssueStatus.values:
+        messages.error(request, "Choose a status.")
+        return _issue_redirect(issue)
+    duplicate_of = None
+    if status == IssueStatus.DUPLICATE:
+        form = DuplicateForm(request.POST, project=project)
+        if not form.is_valid():
+            for error in form.errors.get("number", []):
+                messages.error(request, error)
+            return _issue_redirect(issue, "decide")
+        duplicate_of = form.cleaned_data["number"]
+    try:
+        services.set_status(issue, request.user, status, duplicate_of=duplicate_of)
+    except ValidationError as exc:
+        _error(request, exc)
+    else:
+        messages.success(request, f"{issue.key} is now {issue.get_status_display().lower()}.")
+    return _issue_redirect(issue)
+
+
+@project_view(require="can_edit")
+@require_POST
+def issue_features(request, project, access, number):
+    issue = get_issue(project, number)
+    if request.POST.get("action") == "unlink":
+        feature = get_object_or_404(project.features, pk=request.POST.get("feature"))
+        try:
+            services.unlink_feature(issue, request.user, feature)
+        except ValidationError as exc:
+            _error(request, exc)
+        return _issue_redirect(issue, "features")
+    form = LinkFeatureForm(request.POST, issue=issue)
+    if form.is_valid():
+        try:
+            services.link_feature(issue, request.user, form.cleaned_data["feature"])
+        except ValidationError as exc:
+            _error(request, exc)
+    else:
+        messages.error(request, "Choose a feature to link.")
+    return _issue_redirect(issue, "features")

intent/markdown.py

@@ -1,10 +1,15 @@
-"""Markdown to safe HTML for user-written text (feature descriptions, later issues and comments).
+"""Markdown to safe HTML for user-written text: feature descriptions, issues and comments.
 
 Block elements carry `data-source-lines="start-end"` (1-based, inclusive) so comment threads can
-anchor to lines of the source. Headings shift down one level so user text never adds a second
+anchor to lines of the source.
-<h1> to the page.
+
+Headings are re-levelled so the shallowest heading in the text becomes `heading_base` (h2 by
+default), keeping their relative structure. User text then never adds a second <h1>, and a
+comment that starts at `##` doesn't skip a level under the page's own headings.
 """
 
+from dataclasses import dataclass
+
 import nh3
 from django.utils.safestring import SafeString, mark_safe
 from markdown_it import MarkdownIt
@@ -17,12 +22,14 @@ _ALLOWED_TAGS = nh3.ALLOWED_TAGS - {"img"}
 
 
 def _annotate(state):
+    levels = [int(t.tag[1]) for t in state.tokens if t.type == "heading_open"]
+    shift = state.env.get("heading_base", 2) - min(levels, default=1)
     for token in state.tokens:
         if token.nesting == 1 and token.map:
             start, end = token.map
             token.attrSet("data-source-lines", f"{start + 1}-{end}")
         if token.type in ("heading_open", "heading_close"):
-            token.tag = f"h{min(int(token.tag[1]) + 1, 6)}"
+            token.tag = f"h{max(1, min(int(token.tag[1]) + shift, 6))}"
 
 
 def _build() -> MarkdownIt:
@@ -34,6 +41,51 @@ def _build() -> MarkdownIt:
 _md = _build()
 
 
-def render(text: str) -> SafeString:
+def _clean(html: str) -> SafeString:
-    html = _md.render(text or "")
     return mark_safe(nh3.clean(html, tags=_ALLOWED_TAGS, attributes=_ALLOWED_ATTRIBUTES))
+
+
+def render(text: str, *, heading_base: int = 2) -> SafeString:
+    return _clean(_md.render(text or "", {"heading_base": heading_base}))
+
+
+@dataclass(frozen=True)
+class Block:
+    """One top-level block of rendered Markdown and the source lines it came from."""
+
+    start: int
+    end: int
+    html: SafeString
+
+    @property
+    def anchor(self) -> str:
+        return f"L{self.start}-{self.end}"
+
+
+def render_blocks(text: str) -> list[Block]:
+    """Render each top-level block separately, so each can carry its own comment threads."""
+    env = {"heading_base": 2}
+    tokens = _md.parse(text or "", env)
+    lines = (text or "").splitlines()
+    blocks, i = [], 0
+    while i < len(tokens):
+        j, depth = i, 0
+        while True:
+            depth += tokens[j].nesting
+            if depth <= 0:
+                break
+            j += 1
+        if tokens[i].map:
+            start, end = tokens[i].map
+            # Some blocks (loose lists) claim the blank line after them; don't count it.
+            while end > start + 1 and not lines[end - 1].strip():
+                end -= 1
+            html = _md.renderer.render(tokens[i : j + 1], _md.options, env)
+            blocks.append(Block(start + 1, end, _clean(html)))
+        i = j + 1
+    return blocks
+
+
+def source_lines(text: str, start: int, end: int) -> str:
+    """Lines start..end (1-based, inclusive) of the source."""
+    return "\n".join((text or "").splitlines()[start - 1 : end])

static/css/intent.css

@@ -99,6 +99,59 @@ img {
   outline-offset: 2px;
 }
 
+/* Discussion. Threads and comments are indented by a rule, nothing more. */
+
+.thread,
+.timeline > li {
+  margin-block: 0.75rem;
+}
+
+.thread {
+  padding-inline-start: 0.75rem;
+  border-inline-start: 2px solid color-mix(in srgb, CanvasText 30%, Canvas);
+}
+
+.comment {
+  margin-block: 0.75rem;
+}
+
+.comment > header {
+  font-size: 0.9em;
+}
+
+.timeline {
+  padding: 0;
+  list-style: none;
+}
+
+.actions {
+  display: flex;
+  flex-wrap: wrap;
+  align-items: start;
+  gap: 0.5rem 1rem;
+}
+
+form.inline {
+  display: inline;
+}
+
+.line-comment > summary {
+  font-size: 0.85em;
+}
+
+.block:target,
+.comment:target,
+.thread:target {
+  outline: 2px dashed currentColor;
+  outline-offset: 4px;
+}
+
+pre.quote {
+  white-space: pre-wrap;
+  padding-inline-start: 0.75rem;
+  border-inline-start: 2px solid;
+}
+
 .skip-link {
   position: absolute;
   left: -100vw;

static/js/intent.js

@@ -0,0 +1,9 @@
+// Keyboard and screen-reader focus after HTMX swaps a thread in place.
+// The server marks the element to land on (a new or edited comment, or the thread itself)
+// with data-autofocus; without this, focus would fall back to the top of the page.
+document.addEventListener("htmx:afterSettle", function () {
+  var target = document.querySelector("[data-autofocus]");
+  if (!target) return;
+  target.removeAttribute("data-autofocus");
+  target.focus();
+});

templates/base.html

@@ -8,6 +8,9 @@
   {# Blocking on purpose: applies the saved theme before first paint. #}
   <script src="{% static 'js/theme.js' %}"></script>
   <link rel="stylesheet" href="{% static 'css/intent.css' %}">
+  {# Enhancements only: every form and link works without these. #}
+  <script src="{% static 'js/htmx.min.js' %}" defer></script>
+  <script src="{% static 'js/intent.js' %}" defer></script>
   {% block head %}{% endblock %}
 </head>
 <body>

templates/comments/_comment.html

@@ -0,0 +1,48 @@
+{% comment %}
+  One comment. Needs `c` (prepared by intent.comments.presenters), `thread`, `project`, `focus`.
+  Forms post normally; with HTMX they swap the whole thread (`thread.dom_id`) in place.
+{% endcomment %}
+{% with by=c.author.username|default:"deleted user" comment_id="comment-"|add:c.pk %}
+<article id="{{ comment_id }}" class="comment" tabindex="-1"{% if focus == comment_id %} data-autofocus{% endif %}>
+  <header>
+    <strong>{{ by }}</strong>
+    <a href="#{{ comment_id }}"><time datetime="{{ c.created_at|date:'c' }}">{{ c.created_at|date:"j M Y, H:i" }}</time></a>
+    {% if c.edited_at and not c.is_deleted %}
+      · <a href="{% url 'comments:history' org_slug=project.org.slug project_slug=project.slug comment_id=c.pk %}">edited<span class="visually-hidden"> (see earlier versions of {{ by }}’s comment)</span></a>
+    {% endif %}
+  </header>
+  {% if c.is_deleted %}
+    <p class="muted"><em>Comment deleted.</em></p>
+  {% else %}
+    <div class="prose">{{ c.html }}</div>
+  {% endif %}
+  {% if c.can_edit or c.can_delete %}
+    <div class="actions">
+      {% if c.can_edit %}
+        {% url 'comments:edit' org_slug=project.org.slug project_slug=project.slug comment_id=c.pk as edit_url %}
+        <details>
+          <summary>Edit<span class="visually-hidden"> {{ by }}’s comment</span></summary>
+          <form method="post" action="{{ edit_url }}" hx-post="{{ edit_url }}" hx-target="#{{ thread.dom_id }}" hx-swap="outerHTML">
+            {% csrf_token %}
+            <label for="edit-{{ c.pk }}" class="visually-hidden">Comment text</label>
+            <textarea id="edit-{{ c.pk }}" name="body" rows="4" required>{{ c.body }}</textarea>
+            <button type="submit">Save edit</button>
+          </form>
+        </details>
+      {% endif %}
+      {% if c.can_delete %}
+        {% url 'comments:delete' org_slug=project.org.slug project_slug=project.slug comment_id=c.pk as delete_url %}
+        {# A disclosure rather than a script confirm, so the second step works without JS. #}
+        <details>
+          <summary>Delete<span class="visually-hidden"> {{ by }}’s comment</span></summary>
+          <form method="post" action="{{ delete_url }}" hx-post="{{ delete_url }}" hx-target="#{{ thread.dom_id }}" hx-swap="outerHTML">
+            {% csrf_token %}
+            <p>The text and its edit history will be removed. This can't be undone.</p>
+            <button type="submit">Delete comment</button>
+          </form>
+        </details>
+      {% endif %}
+    </div>
+  {% endif %}
+</article>
+{% endwith %}

templates/comments/_thread.html

@@ -0,0 +1,61 @@
+{% comment %}
+  A feature or line thread. Needs `thread` (prepared), `project`, `access`, `focus`, `error`.
+  Resolved threads start collapsed. This whole element is what HTMX swaps.
+{% endcomment %}
+<div id="{{ thread.dom_id }}" class="thread" tabindex="-1"{% if focus == thread.dom_id %} data-autofocus{% endif %}>
+  {% if error %}<p role="alert"><strong>Error:</strong> {{ error }}</p>{% endif %}
+  <details{% if not thread.is_resolved or error or focus %} open{% endif %}>
+    <summary>
+      Thread by {{ thread.author.username|default:"deleted user" }},
+      {{ thread.live_count }} comment{{ thread.live_count|pluralize }}{% if thread.promoted_to %}, became issue {{ thread.promoted_to.key }}{% elif thread.is_resolved %}, resolved{% endif %}
+    </summary>
+
+    {% if thread.kind == "line" and thread.outdated %}
+      <p class="muted">
+        On lines {{ thread.line_start }}–{{ thread.line_end }} of
+        <a href="{% url 'features:revision' org_slug=project.org.slug project_slug=project.slug feature_key=thread.feature.key revision=thread.revision %}#L{{ thread.line_start }}-{{ thread.line_end }}">revision {{ thread.revision }}</a>,
+        which have changed since:
+      </p>
+      <pre class="quote">{{ thread.quoted }}</pre>
+    {% endif %}
+
+    {% if thread.promoted_to %}
+      <p>Continued in issue <a href="{% url 'issues:detail' org_slug=project.org.slug project_slug=project.slug number=thread.promoted_to.number %}">{{ thread.promoted_to.key }} {{ thread.promoted_to.title }}</a>.</p>
+    {% endif %}
+
+    {% for c in thread.comment_list %}
+      {% include "comments/_comment.html" %}
+    {% endfor %}
+
+    {% if access.can_contribute %}
+      {% url 'comments:reply' org_slug=project.org.slug project_slug=project.slug thread_id=thread.pk as reply_url %}
+      <form method="post" action="{{ reply_url }}" hx-post="{{ reply_url }}" hx-target="#{{ thread.dom_id }}" hx-swap="outerHTML">
+        {% csrf_token %}
+        <label for="reply-{{ thread.pk }}">Reply</label>
+        <textarea id="reply-{{ thread.pk }}" name="body" rows="3" required>{{ thread.draft }}</textarea>
+        <button type="submit">Reply</button>
+      </form>
+    {% endif %}
+
+    {% if thread.can_resolve or thread.can_promote %}
+      <div class="actions">
+        {% if thread.can_resolve %}
+          {% url 'comments:resolve' org_slug=project.org.slug project_slug=project.slug thread_id=thread.pk as resolve_url %}
+          <form method="post" action="{{ resolve_url }}" hx-post="{{ resolve_url }}" hx-target="#{{ thread.dom_id }}" hx-swap="outerHTML">
+            {% csrf_token %}
+            {% if thread.is_resolved %}
+              <input type="hidden" name="resolved" value="0">
+              <button type="submit">Reopen thread</button>
+            {% else %}
+              <input type="hidden" name="resolved" value="1">
+              <button type="submit">Resolve thread</button>
+            {% endif %}
+          </form>
+        {% endif %}
+        {% if thread.can_promote %}
+          <a href="{% url 'comments:promote' org_slug=project.org.slug project_slug=project.slug thread_id=thread.pk %}">Turn into an issue</a>
+        {% endif %}
+      </div>
+    {% endif %}
+  </details>
+</div>

templates/comments/history.html

@@ -0,0 +1,26 @@
+{% extends "projects/base.html" %}
+
+{% block page_title %}Comment history{% endblock %}
+
+{% block project_content %}
+  <p><a href="{{ back }}">Back to the comment</a></p>
+  <h1>Edits to {{ comment.author.username|default:"deleted user" }}’s comment</h1>
+
+  {% if comment.is_deleted %}
+    <p>This comment was deleted, along with its history.</p>
+  {% else %}
+    <section aria-labelledby="current-heading">
+      <h2 id="current-heading">Current, edited <time datetime="{{ comment.edited_at|date:'c' }}">{{ comment.edited_at|date:"j M Y, H:i" }}</time></h2>
+      <pre class="quote">{{ comment.body }}</pre>
+    </section>
+    {% for version in versions reversed %}
+      <section aria-labelledby="version-{{ version.pk }}">
+        <h2 id="version-{{ version.pk }}">
+          {% if forloop.last %}Original{% else %}Earlier version{% endif %},
+          replaced <time datetime="{{ version.created_at|date:'c' }}">{{ version.created_at|date:"j M Y, H:i" }}</time>
+        </h2>
+        <pre class="quote">{{ version.body }}</pre>
+      </section>
+    {% endfor %}
+  {% endif %}
+{% endblock %}

templates/comments/not_posted.html

@@ -0,0 +1,14 @@
+{% extends "projects/base.html" %}
+
+{% block page_title %}Comment not posted{% endblock %}
+
+{% block project_content %}
+  <h1>Your comment wasn't posted</h1>
+  <p role="alert"><strong>Error:</strong> {{ error }}</p>
+  {% if draft %}
+    <p>Here's what you wrote, so you can copy it:</p>
+    <label for="draft">Your comment</label>
+    <textarea id="draft" rows="8" readonly>{{ draft }}</textarea>
+  {% endif %}
+  <p><a href="{{ back }}">Go back</a></p>
+{% endblock %}

templates/comments/promote.html

@@ -0,0 +1,14 @@
+{% extends "projects/base.html" %}
+
+{% block page_title %}New issue from a thread{% endblock %}
+
+{% block project_content %}
+  <p><a href="{{ back }}">Back to the thread</a></p>
+  <h1>New issue from a thread on <span class="muted">{{ thread.feature.key }}</span></h1>
+  <p>The issue will be linked to {{ thread.feature.key }} {{ thread.feature.title }}, and the thread will be resolved with a link to it.</p>
+  <form method="post">
+    {% csrf_token %}
+    {{ form }}
+    <p><button type="submit">Open issue</button></p>
+  </form>
+{% endblock %}

templates/features/detail.html

@@ -37,9 +37,36 @@
 
   <section aria-labelledby="description-heading">
     <h2 id="description-heading" class="visually-hidden">Description</h2>
-    <div class="prose">
+    {% if blocks %}
-      {% if feature.description %}{{ description }}{% else %}<p class="muted">No description yet.</p>{% endif %}
+      {% url 'features:thread_create' org_slug=project.org.slug project_slug=project.slug feature_key=feature.key as thread_create_url %}
-    </div>
+      <div class="prose">
+        {% for block, threads in blocks %}
+          {# Each block of the description can carry its own threads, like lines in a code review. #}
+          <div class="block" id="{{ block.anchor }}">
+            {{ block.html }}
+            {% for thread in threads %}
+              {% include "comments/_thread.html" %}
+            {% endfor %}
+            {% if access.can_contribute %}
+              <details class="line-comment">
+                <summary>Comment<span class="visually-hidden"> on lines {{ block.start }}–{{ block.end }}</span></summary>
+                <form method="post" action="{{ thread_create_url }}">
+                  {% csrf_token %}
+                  <input type="hidden" name="revision" value="{{ feature.current_revision }}">
+                  <input type="hidden" name="line_start" value="{{ block.start }}">
+                  <input type="hidden" name="line_end" value="{{ block.end }}">
+                  <label for="body-{{ block.anchor }}">Comment on lines {{ block.start }}–{{ block.end }}</label>
+                  <textarea id="body-{{ block.anchor }}" name="body" rows="3" required></textarea>
+                  <button type="submit">Comment</button>
+                </form>
+              </details>
+            {% endif %}
+          </div>
+        {% endfor %}
+      </div>
+    {% else %}
+      <p class="muted">No description yet.</p>
+    {% endif %}
   </section>
 
   {% if children %}
@@ -66,4 +93,52 @@
       </ul>
     </section>
   {% endif %}
+
+  <section id="issues" aria-labelledby="issues-heading">
+    <h2 id="issues-heading">Issues</h2>
+    {% if issues %}
+      <ul>
+        {% for issue in issues %}
+          <li>
+            <a href="{% url 'issues:detail' org_slug=project.org.slug project_slug=project.slug number=issue.number %}">{{ issue.key }} {{ issue.title }}</a>
+            <span class="muted">({{ issue.get_status_display|lower }})</span>
+          </li>
+        {% endfor %}
+      </ul>
+    {% else %}
+      <p class="muted">No issues linked.</p>
+    {% endif %}
+    {% if access.can_contribute %}
+      <p><a href="{% url 'issues:create' org_slug=project.org.slug project_slug=project.slug %}?feature={{ feature.key }}">Open an issue about {{ feature.key }}</a></p>
+    {% endif %}
+  </section>
+
+  <section id="discussion" aria-labelledby="discussion-heading">
+    <h2 id="discussion-heading">Discussion</h2>
+    {% for thread in general_threads %}
+      {% include "comments/_thread.html" %}
+    {% empty %}
+      <p class="muted">No comments yet.</p>
+    {% endfor %}
+    {% if access.can_contribute %}
+      <form method="post" action="{% url 'features:thread_create' org_slug=project.org.slug project_slug=project.slug feature_key=feature.key %}">
+        {% csrf_token %}
+        <label for="new-thread">Start a thread about {{ feature.key }}</label>
+        <textarea id="new-thread" name="body" rows="4" required></textarea>
+        <p class="muted">Markdown. To comment on part of the description, use the Comment button below that part.</p>
+        <button type="submit">Comment</button>
+      </form>
+    {% elif not user.is_authenticated and project.open_contribution %}
+      <p><a href="{% url 'account_login' %}?next={{ request.path|urlencode }}">Sign in</a> to join the discussion.</p>
+    {% endif %}
+  </section>
+
+  {% if outdated_threads %}
+    <section aria-labelledby="outdated-heading">
+      <h2 id="outdated-heading">Comments on earlier revisions</h2>
+      {% for thread in outdated_threads %}
+        {% include "comments/_thread.html" %}
+      {% endfor %}
+    </section>
+  {% endif %}
 {% endblock %}

templates/features/form.html

@@ -10,6 +10,13 @@
     <h1>New feature</h1>
   {% endif %}
 
+  {% if issue %}
+    <p role="note">
+      For issue <a href="{% url 'issues:detail' org_slug=project.org.slug project_slug=project.slug number=issue.number %}">{{ issue.key }} {{ issue.title }}</a>.
+      The new revision will be linked to it.
+    </p>
+  {% endif %}
+
   {% if preview %}
     <section aria-labelledby="preview-heading">
       <h2 id="preview-heading">Preview</h2>

templates/features/history.html

@@ -15,6 +15,7 @@
           <th scope="col">Date</th>
           <th scope="col">Author</th>
           <th scope="col">Note</th>
+          <th scope="col">Issues</th>
           <th scope="col">Changed</th>
           {% if rows|length > 1 %}
             <th scope="col">From</th>
@@ -36,6 +37,7 @@
               <td><time datetime="{{ rev.created_at|date:'c' }}">{{ rev.created_at|date:"j M Y, H:i" }}</time></td>
               <td>{{ rev.author.username|default:"unknown" }}</td>
               <td>{{ rev.note }}</td>
+              <td>{% for issue in rev.issues.all %}<a href="{% url 'issues:detail' org_slug=project.org.slug project_slug=project.slug number=issue.number %}">{{ issue.key }}</a>{% if not forloop.last %}, {% endif %}{% empty %}—{% endfor %}</td>
               <td>{{ row.changes|join:", " }}</td>
               {% if rows|length > 1 %}
                 <td>

templates/features/revision.html

@@ -24,7 +24,11 @@
   <section aria-labelledby="description-heading">
     <h2 id="description-heading" class="visually-hidden">Description</h2>
     <div class="prose">
-      {% if snapshot.description %}{{ description }}{% else %}<p class="muted">No description.</p>{% endif %}
+      {% for block in blocks %}
+        <div class="block" id="{{ block.anchor }}">{{ block.html }}</div>
+      {% empty %}
+        <p class="muted">No description.</p>
+      {% endfor %}
     </div>
   </section>
 {% endblock %}

templates/issues/_event.html

@@ -0,0 +1,33 @@
+{% comment %}One timeline event. Needs `e`, `project`.{% endcomment %}
+<p class="event muted">
+  <strong>{{ e.actor.username|default:"deleted user" }}</strong>
+  {% if e.kind == "status" %}
+    {% if e.status == "accepted" %}accepted this issue
+    {% elif e.status == "rejected" %}rejected this issue
+    {% elif e.status == "withdrawn" %}withdrew this issue
+    {% elif e.status == "duplicate" %}marked this a duplicate of
+      {% if e.duplicate_of %}<a href="{% url 'issues:detail' org_slug=project.org.slug project_slug=project.slug number=e.duplicate_of.number %}">{{ e.duplicate_of.key }} {{ e.duplicate_of.title }}</a>{% else %}a deleted issue{% endif %}
+    {% else %}reopened this issue
+    {% endif %}
+  {% elif e.kind == "revision" and e.feature %}
+    {% if e.revision.revision == 1 %}created{% else %}updated{% endif %}
+    <a href="{% url 'features:detail' org_slug=project.org.slug project_slug=project.slug feature_key=e.feature.key %}">{{ e.feature.key }} {{ e.feature.title }}</a>
+    {% if e.revision %}in <a href="{% url 'features:revision' org_slug=project.org.slug project_slug=project.slug feature_key=e.feature.key revision=e.revision.revision %}">revision {{ e.revision.revision }}</a>: {{ e.revision.note }}{% endif %}
+  {% elif e.kind == "linked" and e.feature %}
+    linked <a href="{% url 'features:detail' org_slug=project.org.slug project_slug=project.slug feature_key=e.feature.key %}">{{ e.feature.key }} {{ e.feature.title }}</a>
+  {% elif e.kind == "unlinked" and e.feature %}
+    unlinked <a href="{% url 'features:detail' org_slug=project.org.slug project_slug=project.slug feature_key=e.feature.key %}">{{ e.feature.key }} {{ e.feature.title }}</a>
+  {% elif e.kind == "edited" %}
+    edited this issue
+  {% else %}
+    {{ e.get_kind_display|lower }}
+  {% endif %}
+  · <time datetime="{{ e.created_at|date:'c' }}">{{ e.created_at|date:"j M Y, H:i" }}</time>
+</p>
+{% if e.kind == "edited" %}
+  <details>
+    <summary>Before the edit</summary>
+    <p><strong>{{ e.old_title }}</strong></p>
+    {% if e.old_body %}<div class="prose">{{ e.old_html }}</div>{% else %}<p class="muted">No description.</p>{% endif %}
+  </details>
+{% endif %}

templates/issues/_timeline.html

@@ -0,0 +1,35 @@
+{% comment %}
+  An issue's comments and events, plus the comment form. Needs `issue`, `thread`, `timeline`,
+  `project`, `access`, `focus`, `error`, `draft`. This whole element is what HTMX swaps.
+{% endcomment %}
+<div id="timeline" tabindex="-1"{% if focus == "timeline" %} data-autofocus{% endif %}>
+  {% if timeline %}
+    <ol class="timeline">
+      {% for kind, item in timeline %}
+        <li>
+          {% if kind == "comment" %}
+            {% include "comments/_comment.html" with c=item %}
+          {% else %}
+            {% include "issues/_event.html" with e=item %}
+          {% endif %}
+        </li>
+      {% endfor %}
+    </ol>
+  {% else %}
+    <p class="muted">No comments yet.</p>
+  {% endif %}
+
+  {% if error %}<p role="alert"><strong>Error:</strong> {{ error }}</p>{% endif %}
+  {% if access.can_contribute %}
+    {% url 'comments:reply' org_slug=project.org.slug project_slug=project.slug thread_id=thread.pk as reply_url %}
+    <form method="post" action="{{ reply_url }}" hx-post="{{ reply_url }}" hx-target="#timeline" hx-swap="outerHTML">
+      {% csrf_token %}
+      <label for="new-comment">Add a comment</label>
+      <textarea id="new-comment" name="body" rows="5" required>{{ draft }}</textarea>
+      <p class="muted">Markdown.</p>
+      <button type="submit">Comment</button>
+    </form>
+  {% elif not user.is_authenticated and project.open_contribution %}
+    <p><a href="{% url 'account_login' %}?next={{ request.path|urlencode }}">Sign in</a> to join the discussion.</p>
+  {% endif %}
+</div>

templates/issues/detail.html

@@ -0,0 +1,114 @@
+{% extends "projects/base.html" %}
+
+{% block page_title %}{{ issue.key }} {{ issue.title }}{% endblock %}
+
+{% block project_content %}
+  <h1><span class="muted">{{ issue.key }}</span> {{ issue.title }}</h1>
+  <p>
+    <strong>{{ issue.get_status_display }}</strong>{% if issue.duplicate_of %} duplicate of <a href="{% url 'issues:detail' org_slug=project.org.slug project_slug=project.slug number=issue.duplicate_of.number %}">{{ issue.duplicate_of.key }} {{ issue.duplicate_of.title }}</a>{% endif %}.
+    Opened by {{ issue.author.username|default:"deleted user" }}
+    on <time datetime="{{ issue.created_at|date:'c' }}">{{ issue.created_at|date:"j M Y" }}</time>.
+    {% if promoted_url %}Started as <a href="{{ promoted_url }}">a comment thread on {{ promoted_from.feature.key }}</a>.{% endif %}
+  </p>
+  {% if can_edit_issue %}
+    <p><a href="{% url 'issues:edit' org_slug=project.org.slug project_slug=project.slug number=issue.number %}">Edit issue</a></p>
+  {% endif %}
+
+  <section aria-labelledby="body-heading">
+    <h2 id="body-heading" class="visually-hidden">Description</h2>
+    <div class="prose">
+      {% if issue.body %}{{ body }}{% else %}<p class="muted">No description.</p>{% endif %}
+    </div>
+  </section>
+
+  <section id="features" aria-labelledby="features-heading">
+    <h2 id="features-heading">Features</h2>
+    {% if features %}
+      <ul>
+        {% for feature in features %}
+          <li>
+            <a href="{% url 'features:detail' org_slug=project.org.slug project_slug=project.slug feature_key=feature.key %}">{{ feature.key }} {{ feature.title }}</a>
+            {% if access.can_edit %}
+              <form method="post" action="{% url 'issues:features' org_slug=project.org.slug project_slug=project.slug number=issue.number %}" class="inline">
+                {% csrf_token %}
+                <input type="hidden" name="action" value="unlink">
+                <input type="hidden" name="feature" value="{{ feature.pk }}">
+                <button type="submit">Unlink <span class="visually-hidden">{{ feature.key }}</span></button>
+              </form>
+            {% endif %}
+          </li>
+        {% endfor %}
+      </ul>
+    {% else %}
+      <p class="muted">Not linked to any feature.</p>
+    {% endif %}
+
+    {% if access.can_edit %}
+      {% if link_form.fields.feature.queryset.exists %}
+        <form method="post" action="{% url 'issues:features' org_slug=project.org.slug project_slug=project.slug number=issue.number %}">
+          {% csrf_token %}
+          <input type="hidden" name="action" value="link">
+          {{ link_form }}
+          <button type="submit">Link feature</button>
+        </form>
+      {% endif %}
+      <p>Change features for this issue. The revision is tied to {{ issue.key }}{% if issue.is_open %}, and you can accept the issue as you save{% endif %}.</p>
+      <ul>
+        <li><a href="{% url 'features:create' org_slug=project.org.slug project_slug=project.slug %}?issue={{ issue.number }}">Create a feature from {{ issue.key }}</a></li>
+        {% for feature in features %}
+          <li><a href="{% url 'features:edit' org_slug=project.org.slug project_slug=project.slug feature_key=feature.key %}?issue={{ issue.number }}">Update {{ feature.key }} for {{ issue.key }}</a></li>
+        {% endfor %}
+      </ul>
+    {% endif %}
+  </section>
+
+  {% if duplicates %}
+    <section aria-labelledby="duplicates-heading">
+      <h2 id="duplicates-heading">Duplicates</h2>
+      <ul>
+        {% for dup in duplicates %}
+          <li><a href="{% url 'issues:detail' org_slug=project.org.slug project_slug=project.slug number=dup.number %}">{{ dup.key }} {{ dup.title }}</a></li>
+        {% endfor %}
+      </ul>
+    </section>
+  {% endif %}
+
+  {% if access.can_edit or can_withdraw %}
+    {% url 'issues:status' org_slug=project.org.slug project_slug=project.slug number=issue.number as status_url %}
+    <section id="decide" aria-labelledby="decide-heading">
+      <h2 id="decide-heading">Decision</h2>
+      {% if issue.is_open %}
+        <form method="post" action="{{ status_url }}">
+          {% csrf_token %}
+          {% if access.can_edit %}
+            <button type="submit" name="status" value="accepted">Accept</button>
+            <button type="submit" name="status" value="rejected">Reject</button>
+          {% endif %}
+          {% if can_withdraw %}
+            <button type="submit" name="status" value="withdrawn">Withdraw</button>
+          {% endif %}
+        </form>
+        {% if access.can_edit %}
+          <form method="post" action="{{ status_url }}">
+            {% csrf_token %}
+            <input type="hidden" name="status" value="duplicate">
+            {{ duplicate_form }}
+            <button type="submit">Mark as duplicate</button>
+          </form>
+        {% endif %}
+      {% elif access.can_edit or issue.status == "withdrawn" %}
+        <form method="post" action="{{ status_url }}">
+          {% csrf_token %}
+          <button type="submit" name="status" value="open">Reopen</button>
+        </form>
+      {% else %}
+        <p class="muted">This issue is closed.</p>
+      {% endif %}
+    </section>
+  {% endif %}
+
+  <section aria-labelledby="discussion-heading">
+    <h2 id="discussion-heading">Discussion</h2>
+    {% include "issues/_timeline.html" %}
+  </section>
+{% endblock %}

templates/issues/form.html

@@ -0,0 +1,31 @@
+{% extends "projects/base.html" %}
+
+{% block page_title %}{% if issue %}Edit {{ issue.key }}{% else %}New issue{% endif %}{% endblock %}
+
+{% block project_content %}
+  {% if issue %}
+    <h1>Edit <span class="muted">{{ issue.key }}</span> {{ issue.title }}</h1>
+  {% else %}
+    <h1>New issue</h1>
+  {% endif %}
+
+  {% if preview %}
+    <section aria-labelledby="preview-heading">
+      <h2 id="preview-heading">Preview</h2>
+      <div class="prose preview">{{ preview }}</div>
+      <p class="muted">Not saved yet.</p>
+    </section>
+  {% elif preview is not None %}
+    <p class="muted">Nothing to preview: the description is empty.</p>
+  {% endif %}
+
+  <form method="post">
+    {% csrf_token %}
+    {{ form }}
+    <p>
+      {# Save comes first so pressing Enter in a text field saves rather than previews. #}
+      <button type="submit">{% if issue %}Save issue{% else %}Open issue{% endif %}</button>
+      <button type="submit" name="preview" value="1">Preview description</button>
+    </p>
+  </form>
+{% endblock %}

templates/issues/list.html

@@ -0,0 +1,46 @@
+{% extends "projects/base.html" %}
+
+{% block page_title %}Issues{% endblock %}
+
+{% block project_content %}
+  <h1>Issues</h1>
+  {% if access.can_contribute %}
+    <p><a href="{% url 'issues:create' org_slug=project.org.slug project_slug=project.slug %}">New issue</a></p>
+  {% endif %}
+
+  <nav aria-label="Filter issues">
+    <ul>
+      {% for key, label in filters %}
+        <li><a href="?status={{ key }}"{% if key == current %} aria-current="page"{% endif %}>{{ label }}</a></li>
+      {% endfor %}
+    </ul>
+  </nav>
+
+  {% if issues %}
+    <table>
+      <caption class="visually-hidden">{% for key, label in filters %}{% if key == current %}{{ label }}{% endif %}{% endfor %} issues</caption>
+      <thead>
+        <tr>
+          <th scope="col">Issue</th>
+          <th scope="col">Status</th>
+          <th scope="col">Features</th>
+          <th scope="col">Opened by</th>
+          <th scope="col">Updated</th>
+        </tr>
+      </thead>
+      <tbody>
+        {% for issue in issues %}
+          <tr>
+            <th scope="row"><a href="{% url 'issues:detail' org_slug=project.org.slug project_slug=project.slug number=issue.number %}">{{ issue.key }} {{ issue.title }}</a></th>
+            <td>{{ issue.get_status_display }}</td>
+            <td>{% for f in issue.features.all %}{{ f.key }}{% if not forloop.last %}, {% endif %}{% empty %}—{% endfor %}</td>
+            <td>{{ issue.author.username|default:"deleted user" }}</td>
+            <td><time datetime="{{ issue.updated_at|date:'c' }}">{{ issue.updated_at|date:"j M Y" }}</time></td>
+          </tr>
+        {% endfor %}
+      </tbody>
+    </table>
+  {% else %}
+    <p>No {% if current != "all" %}{{ current }} {% endif %}issues.</p>
+  {% endif %}
+{% endblock %}

templates/projects/base.html

@@ -17,6 +17,7 @@
     <ul>
       <li><a href="{% url 'projects:home' org_slug=project.org.slug project_slug=project.slug %}">Feature tree</a></li>
       <li><a href="{% url 'features:list' org_slug=project.org.slug project_slug=project.slug %}">All features</a></li>
+      <li><a href="{% url 'issues:list' org_slug=project.org.slug project_slug=project.slug %}">Issues</a></li>
       {% if access.can_edit %}
         <li><a href="{% url 'projects:members' org_slug=project.org.slug project_slug=project.slug %}">Members</a></li>
       {% endif %}

tests/conftest.py

@@ -64,3 +64,18 @@ def editor(make_user, org, project):
     OrgMembership.objects.create(org=org, user=user)
     ProjectMembership.objects.create(project=project, user=user)
     return user
+
+
+@pytest.fixture
+def open_project(project):
+    """The project, made public and open to contributions from any signed-in user."""
+    project.visibility = Visibility.PUBLIC
+    project.open_contribution = True
+    project.save()
+    return project
+
+
+@pytest.fixture
+def outsider(make_user):
+    """A signed-in user with no role in the org."""
+    return make_user("uma")

tests/test_a11y.py

@@ -1,7 +1,9 @@
 import pytest
 from django.urls import reverse
 
+from intent.comments.services import edit_comment, reply, start_feature_thread
 from intent.features.services import create_feature, update_feature
+from intent.issues.services import create_issue, set_status, update_issue
 from intent.orgs.services import invite
 
 from .a11y import assert_accessible_html
@@ -13,6 +15,20 @@ def populated(project, owner, make_user, org):
     child = create_feature(project, owner, title="Sign in", parent=parent)
     update_feature(child, owner, note="Detail", description="Steps\n\n1. One\n2. Two\n")
     invite(org, owner, email="new@example.com")
+
+    # Discussion: a line thread that goes outdated, a current one, a general one, an issue.
+    old = start_feature_thread(child, owner, body="# Old\n\nOn steps", revision=2,
+                               line_start=1, line_end=1)  # fmt: skip
+    update_feature(child, owner, note="Reword", description="Steps\n\n1. One\n2. Two\n3. Three\n")
+    start_feature_thread(child, owner, body="On the list", revision=3, line_start=3, line_end=5)
+    general = start_feature_thread(child, owner, body="General")
+    reply(general, owner, body="## Reply heading")
+    edit_comment(general.comments.first(), owner, body="General, edited")
+    reply(old, owner, body="Still relevant?")
+    issue = create_issue(project, owner, title="Bug", body="# Heading\n\nText", features=[child])
+    reply(issue.threads.get(), owner, body="### Deep heading")
+    update_issue(issue, owner, title="Bug!", body="## New")
+    set_status(issue, owner, "rejected")
     return child
 
 
@@ -38,9 +54,26 @@ def _pages(org, project, feature):
         reverse("features:history", kwargs=fk),
         reverse("features:revision", kwargs={**fk, "revision": 1}),
         reverse("features:compare", kwargs=fk),
+        reverse("features:create", kwargs=pk) + "?issue=1",
+        reverse("features:edit", kwargs=fk) + "?issue=1",
+        reverse("issues:list", kwargs=pk),
+        reverse("issues:list", kwargs=pk) + "?status=closed",
+        reverse("issues:create", kwargs=pk),
+        reverse("issues:detail", kwargs={**pk, "number": 1}),
+        reverse("issues:edit", kwargs={**pk, "number": 1}),
+        reverse("comments:promote", kwargs={**pk, "thread_id": _thread_id(feature)}),
+        reverse("comments:history", kwargs={**pk, "comment_id": _edited_comment_id(feature)}),
     ]
 
 
+def _thread_id(feature):
+    return feature.threads.filter(kind="feature").get().pk
+
+
+def _edited_comment_id(feature):
+    return feature.threads.filter(kind="feature").get().comments.first().pk
+
+
 def test_signed_in_pages(client, owner, org, project, populated):
     client.force_login(owner)
     for path in _pages(org, project, populated):
@@ -52,6 +85,29 @@ def test_signed_in_pages(client, owner, org, project, populated):
             raise AssertionError(f"{path}: {exc}") from None
 
 
+def test_outsider_pages_on_open_project(client, outsider, org, project, populated):
+    project.visibility, project.open_contribution = "public", True
+    project.save()
+    client.force_login(outsider)
+    pk = {"org_slug": org.slug, "project_slug": project.slug}
+    for path in [
+        reverse("features:detail", kwargs={**pk, "feature_key": populated.key}),
+        reverse("issues:detail", kwargs={**pk, "number": 1}),
+    ]:
+        assert_accessible_html(client.get(path).content.decode())
+
+
+def test_comment_not_posted_page(client, owner, project, populated):
+    client.force_login(owner)
+    url = reverse(
+        "features:thread_create",
+        kwargs={"org_slug": "catbriar", "project_slug": "intent", "feature_key": populated.key},
+    )
+    response = client.post(url, {"body": "x", "revision": 1, "line_start": 1, "line_end": 1})
+    assert response.status_code == 400
+    assert_accessible_html(response.content.decode())
+
+
 @pytest.mark.parametrize(
     "html, problem",
     [

tests/test_accounts.py

@@ -75,3 +75,8 @@ def test_staff_cannot_grant_staff_without_superuser(client, make_user):
     target = make_user("tina")
     page = client.get(reverse("admin:accounts_user_change", args=[target.pk])).content.decode()
     assert 'name="is_superuser"' not in page and 'name="is_staff"' not in page
+
+
+def test_admin_pages_for_issues_and_threads_render(admin_client, db):
+    for name in ["admin:issues_issue_changelist", "admin:comments_commentthread_changelist"]:
+        assert admin_client.get(reverse(name)).status_code == 200

tests/test_comments.py

@@ -0,0 +1,261 @@
+import pytest
+from django.core.exceptions import PermissionDenied, ValidationError
+from django.urls import reverse
+
+from intent.comments import services
+from intent.comments.models import Comment, CommentThread, ThreadKind
+from intent.features.services import create_feature, update_feature
+from intent.issues.models import IssueStatus
+from intent.issues.services import create_issue, promote_thread, set_status
+
+DESCRIPTION = "Intro line\n\nSecond para\nwraps here.\n"
+
+
+def furl(name, feature, **kwargs):
+    kwargs = {
+        "org_slug": "catbriar",
+        "project_slug": "intent",
+        "feature_key": feature.key,
+        **kwargs,
+    }
+    return reverse(f"features:{name}", kwargs=kwargs)
+
+
+def curl(name, **kwargs):
+    return reverse(
+        f"comments:{name}", kwargs={"org_slug": "catbriar", "project_slug": "intent", **kwargs}
+    )
+
+
+@pytest.fixture
+def feature(open_project, owner):
+    return create_feature(open_project, owner, title="Sign in", description=DESCRIPTION)
+
+
+@pytest.fixture
+def thread(feature, outsider):
+    return services.start_feature_thread(feature, outsider, body="Why two paragraphs?")
+
+
+def test_line_thread_must_match_current_revision_and_lines(feature, outsider, owner):
+    t = services.start_feature_thread(
+        feature, outsider, body="Hm", revision=1, line_start=3, line_end=4
+    )
+    assert t.kind == ThreadKind.LINE
+    with pytest.raises(ValidationError, match="changed"):
+        services.start_feature_thread(
+            feature, outsider, body="x", revision=2, line_start=1, line_end=1
+        )
+    with pytest.raises(ValidationError):
+        services.start_feature_thread(
+            feature, outsider, body="x", revision=1, line_start=3, line_end=9
+        )
+    with pytest.raises(ValidationError):
+        services.start_feature_thread(feature, outsider, body="  ")
+
+
+def test_private_project_outsiders_cannot_comment(project, owner, make_user):
+    feature = create_feature(project, owner, title="Secret")
+    with pytest.raises(PermissionDenied):
+        services.start_feature_thread(feature, make_user(), body="hi")
+
+
+def test_edit_keeps_history_and_only_author_edits(thread, outsider, owner):
+    comment = thread.comments.get()
+    with pytest.raises(PermissionDenied):
+        services.edit_comment(comment, owner, body="Rewritten")
+    services.edit_comment(comment, outsider, body="Why two?")
+    comment.refresh_from_db()
+    assert comment.edited_at and comment.edits.get().body == "Why two paragraphs?"
+    with pytest.raises(ValidationError):
+        services.edit_comment(comment, outsider, body="Why two?")
+
+
+def test_delete_leaves_tombstone_and_drops_history(thread, outsider, make_user, owner, editor):
+    comment = thread.comments.get()
+    services.edit_comment(comment, outsider, body="Edited")
+    with pytest.raises(PermissionDenied):
+        services.delete_comment(comment, make_user())
+    with pytest.raises(PermissionDenied):
+        services.delete_comment(comment, editor)  # Collaborators don't moderate; owners do.
+    services.delete_comment(comment, owner)
+    comment.refresh_from_db()
+    assert comment.is_deleted and comment.body == "" and not comment.edits.exists()
+    assert comment.deleted_by == owner
+
+
+def test_resolve_by_thread_author_or_team(thread, outsider, editor, make_user):
+    with pytest.raises(PermissionDenied):
+        services.set_resolved(thread, make_user(), True)
+    services.set_resolved(thread, outsider, True)
+    assert thread.is_resolved
+    services.set_resolved(thread, editor, False)
+    assert not thread.is_resolved
+
+
+def test_issue_threads_cannot_be_resolved(open_project, outsider, owner):
+    issue = create_issue(open_project, outsider, title="Bug")
+    with pytest.raises(PermissionDenied):
+        services.set_resolved(issue.threads.get(), owner, True)
+
+
+def test_promote_by_author_or_team_only(thread, feature, outsider, make_user, editor):
+    services.reply(thread, editor, body="Good question")
+    with pytest.raises(PermissionDenied):
+        promote_thread(thread, make_user(), title="X", body="")
+    issue = promote_thread(thread, outsider, title="Two paragraphs", body="Quoted")
+    thread.refresh_from_db()
+    assert thread.promoted_to == issue and thread.is_resolved
+    assert list(issue.features.all()) == [feature]
+    assert issue.author == outsider
+    with pytest.raises(PermissionDenied):
+        promote_thread(thread, editor, title="Again", body="")
+
+
+def test_promotion_text_quotes_lines_and_comments(feature, outsider, editor):
+    from intent.issues.services import promotion_text
+
+    t = services.start_feature_thread(
+        feature, outsider, body="Unclear wording", revision=1, line_start=3, line_end=4
+    )
+    services.reply(t, editor, body="Agreed")
+    title, body = promotion_text(t)
+    assert title == "Unclear wording"
+    assert "lines 3–4 of revision 1" in body
+    assert "> Second para\n> wraps here." in body
+    assert "**eddie** wrote:\n\n> Agreed" in body
+
+
+# Views
+
+
+def test_feature_page_shows_line_threads_under_their_block(client, feature, outsider):
+    services.start_feature_thread(
+        feature, outsider, body="About para two", revision=1, line_start=3, line_end=4
+    )
+    client.force_login(outsider)
+    page = client.get(furl("detail", feature)).content.decode()
+    block = page.index('id="L3-4"')
+    assert block < page.index("About para two") < page.index('id="discussion"')
+    assert 'id="body-L1-1"' in page  # A comment form for each block.
+
+
+def test_line_threads_go_outdated_only_when_text_changes(client, feature, outsider, owner):
+    services.start_feature_thread(
+        feature, outsider, body="About para two", revision=1, line_start=3, line_end=4
+    )
+    update_feature(feature, owner, note="Withdraw", status="withdrawn")  # Text unchanged.
+    client.force_login(outsider)
+    page = client.get(furl("detail", feature)).content.decode()
+    assert "Comments on earlier revisions" not in page
+    update_feature(feature, owner, note="Reword", description="Intro\n\nNew text\n")
+    page = client.get(furl("detail", feature)).content.decode()
+    outdated = page.index("Comments on earlier revisions")
+    assert outdated < page.index("About para two")
+    assert "Second para\nwraps here." in page  # The original lines are quoted.
+    assert furl("revision", feature, revision=1) + "#L3-4" in page
+
+
+def test_create_thread_via_form(client, feature, outsider):
+    client.force_login(outsider)
+    response = client.post(furl("thread_create", feature), {"body": "General point"})
+    thread = CommentThread.objects.get()
+    assert response["Location"] == furl("detail", feature) + f"#thread-{thread.pk}"
+    assert thread.kind == ThreadKind.FEATURE
+
+
+def test_stale_line_comment_shows_the_draft(client, feature, outsider, owner):
+    update_feature(feature, owner, note="Edit", description="Changed\n")
+    client.force_login(outsider)
+    response = client.post(
+        furl("thread_create", feature),
+        {"body": "My long thought", "revision": 1, "line_start": 1, "line_end": 1},
+    )
+    assert response.status_code == 400
+    assert b"My long thought" in response.content and b"changed" in response.content
+    assert not CommentThread.objects.exists()
+
+
+def test_reply_without_js_redirects_to_the_comment(client, thread, outsider):
+    client.force_login(outsider)
+    response = client.post(curl("reply", thread_id=thread.pk), {"body": "More"})
+    comment = Comment.objects.get(body="More")
+    assert response["Location"].endswith(f"#comment-{comment.pk}")
+
+
+def test_reply_with_htmx_returns_the_thread_fragment(client, thread, outsider):
+    client.force_login(outsider)
+    response = client.post(
+        curl("reply", thread_id=thread.pk), {"body": "More"}, headers={"HX-Request": "true"}
+    )
+    html = response.content.decode()
+    assert response.status_code == 200
+    assert html.lstrip().startswith(f'<div id="thread-{thread.pk}"')
+    assert "<html" not in html
+    comment = Comment.objects.get(body="More")
+    assert f'id="comment-{comment.pk}" class="comment" tabindex="-1" data-autofocus' in html
+
+
+def test_htmx_empty_reply_keeps_thread_and_shows_error(client, thread, outsider):
+    client.force_login(outsider)
+    response = client.post(
+        curl("reply", thread_id=thread.pk), {"body": " "}, headers={"HX-Request": "true"}
+    )
+    assert response.status_code == 200 and b'role="alert"' in response.content
+
+
+def test_resolve_edit_delete_via_views(client, thread, outsider, owner):
+    comment = thread.comments.get()
+    client.force_login(outsider)
+    client.post(curl("resolve", thread_id=thread.pk), {"resolved": "1"})
+    thread.refresh_from_db()
+    assert thread.is_resolved
+    client.post(curl("edit", comment_id=comment.pk), {"body": "Edited"})
+    history = client.get(curl("history", comment_id=comment.pk)).content.decode()
+    assert "Why two paragraphs?" in history and "Edited" in history
+    client.force_login(owner)
+    client.post(curl("delete", comment_id=comment.pk))
+    comment.refresh_from_db()
+    assert comment.is_deleted
+
+
+def test_threads_from_another_project_are_404(client, thread, org, owner):
+    from intent.projects.services import create_project
+
+    create_project(
+        org, owner, slug="other", name="Other", feature_prefix="OTH", visibility="public",
+        open_contribution=True,
+    )  # fmt: skip
+    client.force_login(owner)
+    other = reverse(
+        "comments:reply",
+        kwargs={"org_slug": "catbriar", "project_slug": "other", "thread_id": thread.pk},
+    )
+    assert client.post(other, {"body": "Sneaky"}).status_code == 404
+
+
+def test_promote_page_prefills_and_creates_issue(client, thread, outsider):
+    client.force_login(outsider)
+    page = client.get(curl("promote", thread_id=thread.pk)).content.decode()
+    assert "Why two paragraphs?" in page
+    response = client.post(
+        curl("promote", thread_id=thread.pk), {"title": "Two paragraphs", "body": "See thread"}
+    )
+    thread.refresh_from_db()
+    issue = thread.promoted_to
+    assert response["Location"].endswith(f"/issues/{issue.number}/")
+    issue_page = client.get(response["Location"]).content.decode()
+    assert f"#thread-{thread.pk}" in issue_page  # Links back to where it started.
+
+
+def test_someone_elses_thread_cannot_be_promoted_by_outsider(client, thread, make_user):
+    client.force_login(make_user())
+    assert client.get(curl("promote", thread_id=thread.pk)).status_code == 403
+
+
+def test_closed_issue_still_accepts_comments(client, open_project, outsider, editor):
+    issue = create_issue(open_project, outsider, title="Bug")
+    set_status(issue, editor, IssueStatus.REJECTED)
+    client.force_login(outsider)
+    client.post(curl("reply", thread_id=issue.threads.get().pk), {"body": "Why rejected?"})
+    assert Comment.objects.filter(body="Why rejected?").exists()

tests/test_example_flow.py

@@ -0,0 +1,136 @@
+"""The example flow from docs/concept.md, steps 1–7, driven through the views like a browser."""
+
+from django.urls import reverse
+
+from intent.comments.models import CommentThread
+from intent.features.models import Feature
+from intent.issues.models import Issue, IssueStatus
+
+P = {"org_slug": "catbriar", "project_slug": "intent"}
+
+
+def issue_url(name, number, **kwargs):
+    return reverse(f"issues:{name}", kwargs={**P, "number": number, **kwargs})
+
+
+def feature_url(name, key, **kwargs):
+    return reverse(f"features:{name}", kwargs={**P, "feature_key": key, **kwargs})
+
+
+def reply_url(thread):
+    return reverse("comments:reply", kwargs={**P, "thread_id": thread.pk})
+
+
+def test_example_flow(client, open_project, outsider, editor):
+    # 1. A general user creates a new issue in a project.
+    client.force_login(outsider)
+    client.post(
+        reverse("issues:create", kwargs=P),
+        {"title": "Remember me on shared computers", "body": "Sessions last too long."},
+    )
+    issue = Issue.objects.get()
+
+    # 2. Users, including team members, discuss in comments on the issue.
+    issue_thread = issue.threads.get()
+    client.post(reply_url(issue_thread), {"body": "Public library computers especially."})
+    client.force_login(editor)
+    client.post(reply_url(issue_thread), {"body": "Agreed, let's define this."})
+
+    # 3. A team member accepts the issue and creates a feature from it, linked to the issue.
+    create = reverse("features:create", kwargs=P) + f"?issue={issue.number}"
+    client.post(
+        create,
+        {
+            "title": "Session length",
+            "description": "Sessions end after 12 hours.\n\nShared computers end at close.\n",
+            "note": "",
+            "accept_issue": "on",
+        },
+    )
+    issue.refresh_from_db()
+    feature = Feature.objects.get()
+    assert issue.status == IssueStatus.ACCEPTED
+    assert list(issue.features.all()) == [feature]
+    assert feature.revisions.get().issues.get() == issue
+
+    # 4. The team member updates the feature's status manually.
+    client.post(
+        feature_url("edit", feature.key),
+        {
+            "title": feature.title,
+            "description": feature.description,
+            "status": "withdrawn",
+            "note": "Paused until the login rework.",
+        },
+    )
+    feature.refresh_from_db()
+    assert (feature.status, feature.current_revision) == ("withdrawn", 2)
+    client.post(
+        feature_url("edit", feature.key),
+        {
+            "title": feature.title,
+            "description": feature.description,
+            "status": "active",
+            "note": "Back on.",
+        },
+    )
+
+    # 5. Later, a user starts a comment thread on lines of the feature.
+    client.force_login(outsider)
+    client.post(
+        feature_url("thread_create", feature.key),
+        {"body": "What counts as close?", "revision": 3, "line_start": 3, "line_end": 3},
+    )
+    thread = CommentThread.objects.get(feature=feature)
+
+    # 6. After some discussion, the user promotes the thread to an issue.
+    client.force_login(editor)
+    client.post(reply_url(thread), {"body": "Browser close, I think."})
+    client.force_login(outsider)
+    promote = reverse("comments:promote", kwargs={**P, "thread_id": thread.pk})
+    client.post(promote, {"title": "Define 'close'", "body": "From the thread."})
+    follow_up = Issue.objects.get(number=2)
+    thread.refresh_from_db()
+    assert thread.promoted_to == follow_up and thread.is_resolved
+    assert list(follow_up.features.all()) == [feature]
+
+    # 7. More discussion, then a team member accepts the issue and updates the feature.
+    client.post(reply_url(follow_up.threads.get()), {"body": "Tab close too?"})
+    client.force_login(editor)
+    client.post(
+        feature_url("edit", feature.key) + f"?issue={follow_up.number}",
+        {
+            "title": feature.title,
+            "description": (
+                "Sessions end after 12 hours.\n\nShared computers end when the browser closes.\n"
+            ),
+            "status": "active",
+            "note": "Define close as browser close.",
+            "accept_issue": "on",
+        },
+    )
+    follow_up.refresh_from_db()
+    feature.refresh_from_db()
+    assert follow_up.status == IssueStatus.ACCEPTED
+    assert feature.current_revision == 4
+    assert feature.revisions.get(revision=4).issues.get() == follow_up
+
+    # The line thread is now outdated, and the feature page shows both issues.
+    page = client.get(feature_url("detail", feature.key)).content.decode()
+    assert "Comments on earlier revisions" in page
+    assert "#1 Remember me on shared computers" in page and "#2 Define" in page
+
+    # 7, alternative: a third issue is rejected but stays linked, so the proposal is visible.
+    client.force_login(outsider)
+    client.post(
+        reverse("issues:create", kwargs=P),
+        {"title": "Never expire sessions", "features": [feature.pk]},
+    )
+    client.force_login(editor)
+    client.post(issue_url("status", 3), {"status": "rejected"})
+    rejected = Issue.objects.get(number=3)
+    assert rejected.status == IssueStatus.REJECTED
+    assert (
+        "#3 Never expire sessions"
+        in client.get(feature_url("detail", feature.key)).content.decode()
+    )

tests/test_issues.py

@@ -0,0 +1,252 @@
+import pytest
+from django.core.exceptions import PermissionDenied, ValidationError
+from django.db import IntegrityError
+from django.urls import reverse
+
+from intent.comments.models import CommentThread, ThreadKind
+from intent.features.services import create_feature, update_feature
+from intent.issues import services
+from intent.issues.models import EventKind, Issue, IssueStatus
+
+
+def iurl(name, project, **kwargs):
+    kwargs = {"org_slug": project.org.slug, "project_slug": project.slug, **kwargs}
+    return reverse(f"issues:{name}", kwargs=kwargs)
+
+
+@pytest.fixture
+def issue(open_project, outsider):
+    return services.create_issue(open_project, outsider, title="Sign in is slow", body="Why?")
+
+
+def test_numbers_are_per_project_and_issue_gets_a_thread(open_project, outsider, issue):
+    second = services.create_issue(open_project, outsider, title="Another")
+    assert (issue.key, second.key) == ("#1", "#2")
+    assert CommentThread.objects.get(issue=issue).kind == ThreadKind.ISSUE
+
+
+def test_outsiders_need_open_contribution(project, outsider):
+    with pytest.raises(PermissionDenied):
+        services.create_issue(project, outsider, title="Nope")
+    project.visibility = "public"
+    project.save()
+    with pytest.raises(PermissionDenied):
+        services.create_issue(project, outsider, title="Still no")
+
+
+def test_title_required(open_project, outsider):
+    with pytest.raises(ValidationError):
+        services.create_issue(open_project, outsider, title="  ")
+
+
+def test_only_team_decides(issue, outsider, editor):
+    with pytest.raises(PermissionDenied):
+        services.set_status(issue, outsider, IssueStatus.ACCEPTED)
+    services.set_status(issue, editor, IssueStatus.REJECTED)
+    issue.refresh_from_db()
+    assert issue.status == IssueStatus.REJECTED and issue.closed_at
+    services.set_status(issue, editor, IssueStatus.OPEN)
+    issue.refresh_from_db()
+    assert issue.is_open and issue.closed_at is None
+    assert [e.status for e in issue.events.all()] == ["rejected", "open"]
+
+
+def test_author_withdraws_and_reopens_own_issue(issue, outsider, make_user):
+    with pytest.raises(PermissionDenied):
+        services.set_status(issue, make_user(), IssueStatus.WITHDRAWN)
+    services.set_status(issue, outsider, IssueStatus.WITHDRAWN)
+    services.set_status(issue, outsider, IssueStatus.OPEN)
+    services.set_status(issue, outsider, IssueStatus.WITHDRAWN)
+    issue.refresh_from_db()
+    assert issue.status == IssueStatus.WITHDRAWN
+
+
+def test_author_cannot_reopen_a_rejected_issue(issue, outsider, editor):
+    services.set_status(issue, editor, IssueStatus.REJECTED)
+    with pytest.raises(PermissionDenied):
+        services.set_status(issue, outsider, IssueStatus.OPEN)
+
+
+def test_same_status_is_refused(issue, editor):
+    with pytest.raises(ValidationError):
+        services.set_status(issue, editor, IssueStatus.OPEN)
+
+
+def test_duplicates_need_an_original_and_no_cycles(open_project, outsider, editor, issue):
+    other = services.create_issue(open_project, outsider, title="Slow sign in")
+    with pytest.raises(ValidationError):
+        services.set_status(other, editor, IssueStatus.DUPLICATE)
+    with pytest.raises(ValidationError):
+        services.set_status(other, editor, IssueStatus.DUPLICATE, duplicate_of=other)
+    services.set_status(other, editor, IssueStatus.DUPLICATE, duplicate_of=issue)
+    with pytest.raises(ValidationError):
+        services.set_status(issue, editor, IssueStatus.DUPLICATE, duplicate_of=other)
+    # Reopening clears the link.
+    services.set_status(other, editor, IssueStatus.OPEN)
+    other.refresh_from_db()
+    assert other.duplicate_of is None
+
+
+def test_database_enforces_duplicate_of(issue):
+    with pytest.raises(IntegrityError):
+        Issue.objects.filter(pk=issue.pk).update(status=IssueStatus.DUPLICATE)
+
+
+def test_edit_keeps_old_text_in_timeline(issue, outsider, make_user):
+    with pytest.raises(PermissionDenied):
+        services.update_issue(issue, make_user(), title="Hijack", body="")
+    services.update_issue(issue, outsider, title="Sign in is very slow", body="Why?")
+    event = issue.events.get(kind=EventKind.EDITED)
+    assert event.old_title == "Sign in is slow"
+    with pytest.raises(ValidationError):
+        services.update_issue(issue, outsider, title="Sign in is very slow", body="Why?")
+
+
+def test_link_and_unlink_features(issue, editor, outsider, open_project, owner):
+    feature = create_feature(open_project, owner, title="Sign in")
+    with pytest.raises(PermissionDenied):
+        services.link_feature(issue, outsider, feature)
+    services.link_feature(issue, editor, feature)
+    assert list(feature.issues.all()) == [issue]
+    with pytest.raises(ValidationError):
+        services.link_feature(issue, editor, feature)
+    services.unlink_feature(issue, editor, feature)
+    assert not feature.issues.exists()
+
+
+def test_feature_revision_can_accept_an_issue(issue, editor, open_project, owner):
+    feature = create_feature(open_project, owner, title="Sign in")
+    revision = update_feature(
+        feature, editor, note="Cache sessions", title="Fast sign in", issues=[issue],
+        accept_issues=True,
+    )  # fmt: skip
+    issue.refresh_from_db()
+    assert issue.status == IssueStatus.ACCEPTED
+    assert list(revision.issues.all()) == [issue]
+    assert list(issue.features.all()) == [feature]
+    assert issue.events.filter(kind=EventKind.REVISION, revision=revision).exists()
+
+
+def test_cross_project_issue_cannot_be_tied_to_a_feature(issue, org, owner):
+    from intent.projects.services import create_project
+
+    other = create_project(
+        org, owner, slug="other", name="Other", feature_prefix="OTH", visibility="private",
+        open_contribution=False,
+    )  # fmt: skip
+    with pytest.raises(ValidationError):
+        create_feature(other, owner, title="X", issues=[issue])
+
+
+# Views
+
+
+def test_issue_pages_for_outsider_on_open_project(client, open_project, outsider, issue):
+    client.force_login(outsider)
+    assert client.get(iurl("list", open_project)).status_code == 200
+    assert client.get(iurl("create", open_project)).status_code == 200
+    page = client.get(iurl("detail", open_project, number=1)).content.decode()
+    assert "Sign in is slow" in page
+    assert 'value="accepted"' not in page  # No decision buttons for outsiders.
+    assert 'value="withdrawn"' in page
+
+
+def test_private_issues_are_hidden(client, project, owner, outsider):
+    issue = services.create_issue(project, owner, title="Secret")
+    client.force_login(outsider)
+    assert client.get(iurl("detail", project, number=issue.number)).status_code == 404
+
+
+def test_create_via_form_with_feature_prefill(client, open_project, outsider, owner):
+    feature = create_feature(open_project, owner, title="Sign in")
+    client.force_login(outsider)
+    page = client.get(iurl("create", open_project) + "?feature=INT-1").content.decode()
+    assert f'value="{feature.pk}" selected' in page
+    response = client.post(
+        iurl("create", open_project),
+        {"title": "Faster", "body": "Please", "features": [feature.pk]},
+    )
+    issue = Issue.objects.get(title="Faster")
+    assert response["Location"] == iurl("detail", open_project, number=issue.number)
+    assert list(issue.features.all()) == [feature]
+
+
+def test_status_buttons(client, open_project, editor, issue):
+    client.force_login(editor)
+    client.post(iurl("status", open_project, number=1), {"status": "accepted"})
+    issue.refresh_from_db()
+    assert issue.status == IssueStatus.ACCEPTED
+
+
+def test_duplicate_by_number(client, open_project, editor, outsider, issue):
+    other = services.create_issue(open_project, outsider, title="Again")
+    client.force_login(editor)
+    client.post(iurl("status", open_project, number=2), {"status": "duplicate", "number": 99})
+    other.refresh_from_db()
+    assert other.is_open
+    client.post(iurl("status", open_project, number=2), {"status": "duplicate", "number": 1})
+    other.refresh_from_db()
+    assert other.duplicate_of == issue
+
+
+def test_outsider_cannot_post_status_or_links(client, open_project, outsider, issue, owner):
+    feature = create_feature(open_project, owner, title="Sign in")
+    client.force_login(outsider)
+    assert (
+        client.post(iurl("status", open_project, number=1), {"status": "accepted"}).status_code
+        == 403
+    )
+    assert (
+        client.post(
+            iurl("features", open_project, number=1), {"action": "link", "feature": feature.pk}
+        ).status_code
+        == 403
+    )
+
+
+def test_accept_and_create_feature_from_issue(client, open_project, editor, issue):
+    client.force_login(editor)
+    create = reverse("features:create", kwargs={"org_slug": "catbriar", "project_slug": "intent"})
+    page = client.get(f"{create}?issue=1").content.decode()
+    assert 'value="Sign in is slow"' in page and "Mark issue #1 accepted" in page
+    client.post(
+        f"{create}?issue=1",
+        {"title": "Fast sign in", "description": "Why?", "note": "", "accept_issue": "on"},
+    )
+    issue.refresh_from_db()
+    feature = issue.features.get()
+    assert feature.title == "Fast sign in"
+    assert issue.status == IssueStatus.ACCEPTED
+    assert feature.revisions.get().issues.get() == issue
+
+
+def test_update_feature_for_issue_without_accepting(client, open_project, editor, issue, owner):
+    feature = create_feature(open_project, owner, title="Sign in")
+    client.force_login(editor)
+    edit = reverse(
+        "features:edit",
+        kwargs={"org_slug": "catbriar", "project_slug": "intent", "feature_key": "INT-1"},
+    )
+    page = client.get(f"{edit}?issue=1").content.decode()
+    assert "#1: Sign in is slow" in page
+    client.post(
+        f"{edit}?issue=1",
+        {"title": "Sign in", "description": "Faster.", "status": "active", "note": "Speed"},
+    )
+    issue.refresh_from_db()
+    assert issue.is_open and list(issue.features.all()) == [feature]
+    history = reverse(
+        "features:history",
+        kwargs={"org_slug": "catbriar", "project_slug": "intent", "feature_key": "INT-1"},
+    )
+    assert iurl("detail", open_project, number=1) in client.get(history).content.decode()
+
+
+def test_list_filters(client, open_project, editor, outsider, issue):
+    services.create_issue(open_project, outsider, title="Closed one")
+    services.set_status(Issue.objects.get(number=2), editor, IssueStatus.REJECTED)
+    client.force_login(outsider)
+    open_page = client.get(iurl("list", open_project)).content.decode()
+    closed_page = client.get(iurl("list", open_project) + "?status=closed").content.decode()
+    assert "Sign in is slow" in open_page and "Closed one" not in open_page
+    assert "Closed one" in closed_page and "Sign in is slow" not in closed_page

tests/test_markdown.py

@@ -39,3 +39,21 @@ def test_line_diff_hunks():
     assert ("added", None, 10) in kinds
     assert kinds[0] == ("same", 7, 7)  # three lines of context
     assert line_diff(old, old) == []
+
+
+def test_blocks_split_top_level_markdown_with_line_ranges():
+    from intent.markdown import render_blocks, source_lines
+
+    text = "# Title\n\nPara one\ncontinues.\n\n- a\n- b\n\n```\ncode\n```\n"
+    blocks = render_blocks(text)
+    assert [(b.start, b.end) for b in blocks] == [(1, 1), (3, 4), (6, 7), (9, 11)]
+    assert blocks[0].anchor == "L1-1" and "<h2" in blocks[0].html
+    assert "<li" in blocks[2].html and "<li" not in blocks[1].html
+    assert source_lines(text, 3, 4) == "Para one\ncontinues."
+
+
+def test_heading_base_is_adjustable():
+    assert "<h3" in render("# Deep", heading_base=3)
+    # The shallowest heading lands on the base level, keeping relative structure.
+    html = render("## Two\n\n### Three\n")
+    assert "<h2" in html and "<h3" in html and "<h4" not in html