FIX: Integrate BBCode with the native Discourse Markdown pipeline

.gitignore

@@ -1,3 +1,4 @@
 node_modules
 /gems
 /auto_generated
+.eslintcache

.husky/pre-commit

@@ -1 +1 @@
-yarn lint-staged
+pnpm lint-staged

.npmrc

@@ -1 +1,2 @@
-engine-strict=true
+engine-strict = true
+auto-install-peers = false

Gemfile.lock

@@ -1,80 +1,99 @@
 GEM
   remote: https://rubygems.org/
   specs:
-    activesupport (7.1.3.3)
+    activesupport (8.1.3)
       base64
       bigdecimal
-      concurrent-ruby (~> 1.0, >= 1.0.2)
+      concurrent-ruby (~> 1.0, >= 1.3.1)
       connection_pool (>= 2.2.5)
       drb
       i18n (>= 1.6, < 2)
+      json
+      logger (>= 1.4.2)
       minitest (>= 5.1)
-      mutex_m
-      tzinfo (~> 2.0)
-    ast (2.4.2)
-    base64 (0.2.0)
-    bigdecimal (3.1.8)
-    concurrent-ruby (1.2.3)
-    connection_pool (2.4.1)
-    drb (2.2.1)
-    i18n (1.14.5)
+      securerandom (>= 0.3)
+      tzinfo (~> 2.0, >= 2.0.5)
+      uri (>= 0.13.1)
+    ast (2.4.3)
+    base64 (0.3.0)
+    bigdecimal (4.1.2)
+    concurrent-ruby (1.3.7)
+    connection_pool (3.0.2)
+    drb (2.2.3)
+    i18n (1.15.2)
       concurrent-ruby (~> 1.0)
-    json (2.7.2)
-    language_server-protocol (3.17.0.3)
-    minitest (5.23.1)
-    mutex_m (0.2.0)
-    parallel (1.24.0)
-    parser (3.3.1.0)
+    json (2.20.0)
+    language_server-protocol (3.17.0.6)
+    lint_roller (1.1.0)
+    logger (1.7.0)
+    minitest (6.0.6)
+      drb (~> 2.0)
+      prism (~> 1.5)
+    parallel (2.1.0)
+    parser (3.3.11.1)
       ast (~> 2.4.1)
       racc
     prettier_print (1.2.1)
-    racc (1.8.0)
-    rack (3.0.12)
+    prism (1.9.0)
+    racc (1.8.1)
+    rack (3.2.6)
     rainbow (3.1.1)
-    regexp_parser (2.9.2)
-    rexml (3.3.9)
-    rubocop (1.64.0)
+    regexp_parser (2.12.0)
+    rubocop (1.88.2)
       json (~> 2.3)
-      language_server-protocol (>= 3.17.0)
-      parallel (~> 1.10)
+      language_server-protocol (~> 3.17.0.2)
+      lint_roller (~> 1.1.0)
+      parallel (>= 1.10)
       parser (>= 3.3.0.2)
       rainbow (>= 2.2.2, < 4.0)
-      regexp_parser (>= 1.8, < 3.0)
-      rexml (>= 3.2.5, < 4.0)
-      rubocop-ast (>= 1.31.1, < 2.0)
+      regexp_parser (>= 2.9.3, < 3.0)
+      rubocop-ast (>= 1.49.0, < 2.0)
       ruby-progressbar (~> 1.7)
-      unicode-display_width (>= 2.4.0, < 3.0)
-    rubocop-ast (1.31.3)
-      parser (>= 3.3.1.0)
-    rubocop-capybara (2.20.0)
-      rubocop (~> 1.41)
-    rubocop-discourse (3.8.0)
+      unicode-display_width (>= 2.4.0, < 4.0)
+    rubocop-ast (1.50.0)
+      parser (>= 3.3.7.2)
+      prism (~> 1.7)
+    rubocop-capybara (3.0.0)
+      lint_roller (~> 1.1)
+      rubocop (~> 1.81)
+    rubocop-discourse (3.18.0)
       activesupport (>= 6.1)
-      rubocop (>= 1.59.0)
-      rubocop-capybara (>= 2.0.0)
-      rubocop-factory_bot (>= 2.0.0)
-      rubocop-rails (>= 2.25.0)
-      rubocop-rspec (>= 2.25.0)
-    rubocop-factory_bot (2.25.1)
-      rubocop (~> 1.41)
-    rubocop-rails (2.25.0)
+      lint_roller (>= 1.1.0)
+      rubocop-capybara (>= 2.23.0)
+      rubocop-discourse-base (>= 1.0.0)
+      rubocop-factory_bot (>= 2.27.0)
+      rubocop-rails (>= 2.30.3)
+      rubocop-rspec (>= 3.0.1)
+      rubocop-rspec_rails (>= 2.31.0)
+    rubocop-discourse-base (1.0.0)
+      rubocop (>= 1.80.0)
+    rubocop-factory_bot (2.28.0)
+      lint_roller (~> 1.1)
+      rubocop (~> 1.72, >= 1.72.1)
+    rubocop-rails (2.35.5)
       activesupport (>= 4.2.0)
+      lint_roller (~> 1.1)
       rack (>= 1.1)
-      rubocop (>= 1.33.0, < 2.0)
-      rubocop-ast (>= 1.31.1, < 2.0)
-    rubocop-rspec (2.29.2)
-      rubocop (~> 1.40)
-      rubocop-capybara (~> 2.17)
-      rubocop-factory_bot (~> 2.22)
-      rubocop-rspec_rails (~> 2.28)
-    rubocop-rspec_rails (2.28.3)
-      rubocop (~> 1.40)
+      rubocop (>= 1.75.0, < 2.0)
+      rubocop-ast (>= 1.44.0, < 2.0)
+    rubocop-rspec (3.10.2)
+      lint_roller (~> 1.1)
+      regexp_parser (>= 2.0)
+      rubocop (~> 1.86, >= 1.86.2)
+    rubocop-rspec_rails (2.32.0)
+      lint_roller (~> 1.1)
+      rubocop (~> 1.72, >= 1.72.1)
+      rubocop-rspec (~> 3.5)
     ruby-progressbar (1.13.0)
-    syntax_tree (6.2.0)
+    securerandom (0.4.1)
+    syntax_tree (6.3.0)
       prettier_print (>= 1.2.0)
     tzinfo (2.0.6)
       concurrent-ruby (~> 1.0)
-    unicode-display_width (2.5.0)
+    unicode-display_width (3.2.0)
+      unicode-emoji (~> 4.1)
+    unicode-emoji (4.2.0)
+    uri (1.1.1)
 
 PLATFORMS
   ruby
@@ -84,4 +103,4 @@ DEPENDENCIES
   syntax_tree
 
 BUNDLED WITH
-   2.5.10
+  4.0.15

INTEGRATION_NOTES.md

@@ -0,0 +1,194 @@
+# Discourse integration review — September 2026
+
+## Direction
+
+Use Discourse's native Markdown and core formatting where possible. Keep custom
+BBCode for the additional layout and interaction features. Compatibility fixes
+are split into focused pull requests; this document describes the work under
+review and does not mean every change has merged or been deployed.
+
+The local compatibility work targets Discourse core revision `c9d27d5d2e`.
+Selected public examples from the saved XenForo snapshot are local fixtures,
+not part of this repository: the BBCode guide, BBCode+ guide, and Sock Pile.
+Their original credits remain visible. The full XenForo database was not
+restored and the migration importer was not run.
+
+## Markdown and imported source
+
+- Ordinary Markdown and Discourse's `[b]`, `[i]`, `[u]`, and `[s]` formatting use
+  the native parser when no custom BBCode is present. These tags use Discourse's
+  existing `bbcode-b`, `bbcode-i`, `bbcode-u`, and `bbcode-s` classes.
+- Lists and tables use native Markdown. The proposed XenForo `[list]`, `[*]`,
+  `[table]`, `[tr]`, `[td]`, `[th]`, and `[tf]` handlers have been removed from the
+  compatibility update. Convert imported source to supported syntax, preserving
+  cell contents and checking complex tables individually.
+- Markdown headings remain active inside `[div]` and `[nobr]`. Use `\# label`
+  for a literal hash at the beginning of a line. Old layouts that relied on
+  XenForo treating those lines literally need their source converted; rebaking
+  alone cannot infer which headings an author intended.
+- The proposed automatic repair of missing or misnested closing tags has been
+  removed. Correct malformed source before expecting it to render reliably.
+  The underlying BBob parser can drop content from malformed nested tags, so
+  inspect those posts during migration rather than relying on a successful
+  rebake command as proof of faithful output.
+- Custom layout posts still use the plugin's legacy line-break and whitespace
+  conventions, including paragraph suppression and handling of indented layout
+  markup. They are not a fully native Markdown document model. Core inline
+  formatting also has local replacement handlers when nested in a custom layout.
+
+HTML escaping applies only when restoring text hoisted from code or `[plain]`
+examples. For example, `[code=html]<details>Example</details>[/code]` displays the
+HTML as source. Allowed raw HTML outside examples, including `<details>`, still
+passes through Discourse's normal rendering and sanitizer; HTML comments remain
+hidden. This does not grant permission for arbitrary HTML or script execution.
+
+## Changes under review
+
+The integration work registers BBCode through Discourse's Markdown pipeline,
+uses the same parser bundle for server cooking and browser previews, and
+respects the plugin setting and feature overrides used by chat. Spoilers and
+accordions use native disclosure elements, with animation and decoration
+behavior covered separately. Event-handler cleanup and repeated decoration are
+also reviewed independently from parser behavior.
+
+The admin update replaces the obsolete Handlebars template with `.gjs` and uses
+an authenticated POST request to refresh the parser. Optional BBScript remains
+disabled by default; event-handler cleanup is not a complete security review of
+that interpreter.
+
+Layout fixes form separate review work:
+
+- Parse complete default BBCode options with single or double outer quotes,
+  preserving interior CSS quotes and equals signs in URLs.
+- Align tab labels and their controls while allowing long labels to wrap and
+  retaining keyboard focus.
+- Keep positioned artwork in the author's horizontal scroll container on small
+  screens without adding a second scroll area around the entire post.
+
+These are shared parser or layout fixes, without fixture-specific substitutions.
+Their tests do not establish that every historical design renders faithfully.
+
+## Deployment and rebaking
+
+1. Build the parser bundle after changing `bbcode-src`:
+
+   ```sh
+   pnpm install --frozen-lockfile
+   pnpm build
+   ```
+
+2. Deploy the full plugin, including its regenerated bundles. Restart Discourse
+   web processes and Sidekiq so both use the new renderer. Restart the frontend
+   development build when adding or removing plugin modules.
+3. Correct unsupported or malformed imported source before rebuilding it. Check
+   representative posts in the preview and after saving.
+4. Rebuild existing posts on the destination server. Discourse's standard task,
+   run from its application environment, is:
+
+   ```sh
+   RAILS_ENV=production bundle exec rake posts:rebake
+   ```
+
+   For imported posts, follow the [importer's verified rebake instructions](https://github.com/RpNation/discourse_xf_importer#readme),
+   including a fresh run ID after renderer changes. Do not reuse a completed
+   checkpoint as evidence that the new renderer has processed those posts.
+5. Check failed post IDs and Sidekiq retry/dead jobs. Background post-processing
+   must finish too. Inspect representative rendered posts; job completion alone
+   does not validate a layout's appearance.
+
+These are server deployment instructions. The full import and site-wide rebake
+must not be run on the local development computer.
+
+## HTML/CSS alternatives
+
+### Constrained layouts inside normal posts
+
+This fits Discourse's normal selection, quoting, links, image handling, and
+document sizing most closely. It needs a deliberately restricted language:
+
+1. Parse HTML and allow selected layout/formatting elements and attributes.
+   Remove executable markup, event handlers, forms, and unapproved embeds.
+   Validate URL schemes as well as element names.
+2. Parse CSS, validate class/ID tokens, and rewrite every selector and animation
+   reference into a generated wrapper the author cannot alter. Random suffixes
+   or regular-expression stripping alone are not sufficient.
+3. Limit properties/values and resource URLs. Prevent viewport positioning,
+   global selectors, imports, and rules that target Discourse controls.
+4. Protect layout and paint containment on the wrapper. Containment is useful
+   for positioning/clipping, but does not replace HTML/CSS sanitization.
+5. Preserve readable text for search, email, quoting, and moderation, and test
+   desktop/mobile preview parity.
+
+These restrictions need a compatibility inventory: authors' existing free-form
+designs may depend on CSS that the constrained renderer would reject. A shared
+rendering layer could eventually support both BBCode and constrained HTML input.
+
+### Sandboxed HTML/CSS frames
+
+For substantially freer CSS, an iframe provides a separate document boundary.
+Start with no user scripts, forms, top-level navigation, or same-origin access;
+sanitize the content and apply a restrictive content security policy as well.
+If frames are served from a URL, use a dedicated origin so opening that URL
+directly does not bypass the intended isolation.
+
+This requires more Discourse integration: frame sizing, search and email
+fallbacks, selection/quoting, lightboxes, theme colors, responsive behavior,
+accessibility, and performance with many posts. Any resizing bridge must be
+controlled by the plugin and must not grant arbitrary user scripts access to
+the forum. Avoid treating unrestricted iframes as a drop-in post renderer.
+
+## Current boundaries
+
+The legacy plugin's free-form inline styles and custom class styles are not a
+security boundary. CSS can affect layout outside the intended content area;
+optional `@scope` and random class suffixes do not establish complete isolation.
+The BBScript engines also contain global selector and HTML-construction paths
+that need a dedicated review before expanding their use.
+
+This compatibility work does not introduce unrestricted user HTML or claim that
+the existing BBCode+ language is sandboxed. Optional integrations, such as Font
+Awesome kits and remote image/font hosts, need their normal configuration and
+available resources. Missing BBCode+ features need separate implementation and
+regression coverage.
+
+The copied BBCode+ guide contains script-driven examples that remain inactive
+while BBScript is disabled, and its legacy `[input]` control is not implemented.
+Use the composer's Markdown mode to author and edit BBCode; this work does not
+add a rich-text BBCode editor.
+
+Earlier local screenshots and fixture checks included compatibility behavior
+that was removed during review, including literal hash labels and malformed-tag
+repair. They are not validation of the revised parser. Recheck affected designs
+after source conversion and deployment.
+
+## References
+
+- [HTML iframe sandbox rules](https://html.spec.whatwg.org/multipage/iframe-embed-object.html#attr-iframe-sandbox)
+- [Iframe behavior and tradeoffs](https://developer.mozilla.org/en-US/docs/Web/HTML/Reference/Elements/iframe)
+- [CSS paint containment](https://drafts.csswg.org/css-contain/#paint-containment)
+- [Shadow DOM encapsulation](https://developer.mozilla.org/en-US/docs/Web/API/Web_components/Using_shadow_DOM)
+
+## Focused tests
+
+Inside a Discourse checkout with the relevant plugin changes installed and
+frontend assets built:
+
+```sh
+RAILS_ENV=test LOAD_PLUGINS=1 bundle exec rspec plugins/bbcode/spec/lib/pretty_text_spec.rb
+bundle exec ruby bin/qunit --target bbcode --rails-port 3000 --filter BBCode
+```
+
+Run the admin request specs when testing the separate admin update. Run the
+JavaScript, Ruby, and stylesheet lint checks for the files changed in each pull
+request.
+
+Parser regressions cover native Markdown headings, paragraphs, lists, tables,
+core inline formatting, code examples, allowed raw HTML, and sanitization. Layout
+regressions cover generic attributes rather than copies of user designs.
+Browser unit tests cover interactions and repeated decoration for the modules
+included in each change.
+
+The server tests use synthetic inputs. Real-source fixture content stays outside
+the plugin checkout and should not be committed as test data. Browser unit
+checks and emulated mobile viewports do not establish Safari/iOS compatibility or
+replace a fresh visual review of the affected local fixtures.