Fix: Add viewer hooks and autocmds to hover popup for consistent highlighting

[sirasagi62]

Problem:

Currently, the hover popup only calls helper.fern.renderer.highlight() and helper.fern.renderer.syntax(), which means user customizations made through FernHighlight/FernSyntax autocmds or viewer:highlight/viewer:syntax hooks are not applied to the hover popups.

As a result, fern-specific customizations made in these hooks/autocmds only affect the main window, creating visual inconsistency. This behavior makes it difficult to customize highlighting that is not defined by Fern, such as CursorLine, which is limited to fern.

See also: #283

Solution:

This PR adds viewer:highlight, viewer:syntax hooks and FernHighlight, FernSyntax autocmds to the hover popup's s:apply() function to ensure consistent highlighting between the main fern window and hover popups.

Summary by CodeRabbit

• New Features
  • Added two viewer events (FernSyntax and FernHighlight) during hover popup rendering. These events trigger User autocommands so users can hook into and customize syntax and highlight behavior for hover popups.

_{✏️ Tip: You can customize this high-level summary in your review settings.}

[coderabbitai]

Walkthrough

Inserted two viewer events—viewer:syntax and viewer:highlight—emitted inside s:apply() of the hover popup drawer immediately after calling helper.fern.renderer.syntax() and helper.fern.renderer.highlight(), each triggering corresponding User autocommands.

Changes

Cohort / File(s)	Change Summary
Hover popup drawer — event emissions autoload/fern/internal/drawer/hover_popup.vim	After helper.fern.renderer.syntax() emit viewer:syntax and trigger User FernSyntax; after helper.fern.renderer.highlight() emit viewer:highlight and trigger User FernHighlight. Events are added into the s:apply() render flow immediately following the respective renderer calls.

Sequence Diagram(s)

sequenceDiagram
  participant Drawer as HoverPopup s:apply()
  participant Helper as helper
  participant Renderer as helper.fern.renderer
  participant Events as Vim events (User)
  Drawer->>Renderer: helper.fern.renderer.syntax()
  Renderer-->>Drawer: syntax rendered
  Drawer->>Events: emit viewer:syntax
  Events-->>Events: User FernSyntax autocommand

  Drawer->>Renderer: helper.fern.renderer.highlight()
  Renderer-->>Drawer: highlight applied
  Drawer->>Events: emit viewer:highlight
  Events-->>Events: User FernHighlight autocommand

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Estimated code review effort

🎯 2 (Simple) | ⏱️ ~8 minutes

• Check that event names (viewer:syntax, viewer:highlight) and autocommand names (FernSyntax, FernHighlight) match project conventions.
• Confirm the emissions occur at the intended points (immediately after the renderer calls) and do not break assumptions about render ordering.
• Verify no unintended side effects or duplicate triggers in surrounding logic.

Poem

🐰 I nudged a whisper into the flow,

viewer:syntax then viewer:highlight aglow,
Hooks hop in, a tiny parade,
Rendered fields bright in the shade,
A rabbit cheers for events now made.

Pre-merge checks and finishing touches

✅ Passed checks (3 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly and specifically describes the main change: adding viewer hooks and autocommands to hover popups to fix inconsistent highlighting, which directly aligns with the changeset.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.

✨ Finishing touches

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Post copyable unit tests in a comment

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📜 Recent review details

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Review profile: CHILL

Plan: Pro

📥 Commits

Reviewing files that changed from the base of the PR and between ecebdb4 and 0118386.

📒 Files selected for processing (1)

• autoload/fern/internal/drawer/hover_popup.vim (1 hunks)

🚧 Files skipped from review as they are similar to previous changes (1)

• autoload/fern/internal/drawer/hover_popup.vim

⏰ Context from checks skipped due to timeout of 90000ms. You can increase the timeout in your CodeRabbit configuration to a maximum of 15 minutes (900000ms). (1)

• GitHub Check: test (macos-latest, v8.2.5136)

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[coderabbitai]

Actionable comments posted: 1

📜 Review details

Configuration used: CodeRabbit UI

Review profile: CHILL

Plan: Pro

📥 Commits

Reviewing files that changed from the base of the PR and between cb60188 and ecebdb4.

📒 Files selected for processing (1)

• autoload/fern/internal/drawer/hover_popup.vim (1 hunks)