Configurable annotation marker

[jknlsn]

Configurable annotation marker

Adds --annotation-marker (env: REVDIFF_ANNOTATION_MARKER, config: annotation-marker) to let users swap the 💬 prefix for something else. Defaults to the emoji so nothing changes for existing setups.

All five render sites now go through annotPrefix() / annotFilePrefix() helpers instead of hardcoding the emoji. Input width and wrap-continuation indent use lipgloss.Width() so everything stays aligned regardless of marker width.

The marker is render-only — structured output still uses ## path:N (T) headers, so saved annotations stay portable between users with different markers. Flag lives on top-level options rather than Colors since it's not a colour value.

Empty string is a valid choice: --annotation-marker "" gives you a bare space prefix. The CLI default tag handles "not set", so empty only happens when you ask for it explicitly.

SKILL.md unchanged — this is a user-preference flag like --theme or --wrap, not something agents should auto-derive from context. Users set it in their config or env once.

Closes #184

[umputun]

few findings, biggest one is a width regression:

1. input width drops 2 cols at app/ui/annotate.go:100,160. Old constants 6/12 were 1 (cursor) + prefix_width + 2 (border margin) per the original comments, the new 1 + lipgloss.Width(prefix) drops the +2. With the default marker the input is now 4/10 instead of 6/12, two columns wider than before, can bleed into the right padding on narrow panes. Either restore the +2 (2 + lipgloss.Width(...)) or document why the margin is no longer needed. Worth adding a regression test that pins absolute input width for the default marker plus at least one wide and one empty marker so this kind of drift surfaces in CI.

2. testifylint will fail CI at app/config_test.go:427,454. assert.Equal(t, "", opts.AnnotationMarker) should be assert.Empty(t, opts.AnnotationMarker).

3. gofmt struct-field alignment at app/main.go:206-213, app/ui/model_test.go:148-160, app/ui/annotate_test.go:510-520, 546-558. Inserting AnnotationMarker: widened the longest key but the surrounding fields were not re-aligned. make fmt cleans it up.

4. stale test comment at app/ui/annotate_test.go:1137. "(12-6=6)" references the old hardcoded constants. The numerical result is still 6 under the new math (10-4=6), but the parenthetical no longer matches what is actually computed.

5. weak assertion in TestModel_EmptyAnnotationMarkerExplicit. assert.Contains(t, rendered, " bare note", ...) would pass even if a hardcoded " 💬 " fallback regressed since the substring would still appear after the prefix. Anchor with a regex or full-row equality on the prefix.

6. per-render alloc in annotPrefix() / annotFilePrefix(). Both concat a new string on every call from hot paths (composeAnnotationRows, annotationContinuationIndent, annotationPrefixBody, renderAnnotationOrInput, renderFileAnnotationHeader). Marker is immutable post-NewModel, would be cheaper to cache once on modelConfigState alongside annotationMarker.

[Copilot]

Pull request overview

This PR adds a configurable annotation marker so users can replace the hardcoded 💬 prefix with a custom string via --annotation-marker (env REVDIFF_ANNOTATION_MARKER, config annotation-marker) while keeping the existing default behavior.

Changes:

• Introduces the --annotation-marker option (CLI/env/config) and wires it through main -> ui.ModelConfig -> ui.Model.
• Replaces hardcoded annotation marker render strings with annotPrefix() / annotFilePrefix() helpers and adjusts width/indent logic using lipgloss.Width().
• Updates documentation and adds/extends tests for default, custom, and empty markers.

Reviewed changes

Copilot reviewed 12 out of 12 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
site/docs.html	Documents the new --annotation-marker option in the generated options table.
README.md	Adds the new flag/env var to the CLI options table.
plugins/codex/skills/revdiff/references/config.md	Documents the new flag/env/config key in the reference table.
.claude-plugin/skills/revdiff/references/config.md	Mirrors config reference documentation update for the claude plugin.
app/ui/model.go	Extends ModelConfig / internal config state to carry AnnotationMarker into UI rendering.
app/ui/model_test.go	Updates the shared test model factory to set a default annotation marker.
app/ui/diffview.go	Switches annotation rendering call sites to use the new prefix helpers; updates continuation indent logic.
app/ui/annotate.go	Adds annotPrefix() / annotFilePrefix() helpers and updates annotation input width calculation to use lipgloss.Width().
app/ui/annotate_test.go	Adds coverage for custom and empty annotation markers and updates imports/config for NewModel.
app/main.go	Plumbs opts.AnnotationMarker into ui.ModelConfig.
app/config.go	Adds the new CLI/env/config option with default 💬.
app/config_test.go	Adds tests covering flag/env/config parsing for the new option (including explicit empty).

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[umputun]

all 6 round-1 items fixed, verified locally. Tests green, lint 0 issues.

two copilot inline comments from round 1 still worth a look:

1. indent inference ambiguity at app/ui/diffview.go:701-710. Real edge-case bug. annotationContinuationIndent uses HasPrefix(firstLogicalLine, m.annotFilePrefix()) to pick indent width, but a line-level annotation whose body starts with file: produces 💬 file: ... and matches the file-prefix branch, so continuation rows get the 9-space indent instead of 3. Triggers on multi-line line-annotations only. Worse with empty marker since annotFilePrefix becomes " file: " and any body starting with file: mis-matches. Fix is trivial since composeAnnotationRows already has prefix in scope: drop the HasPrefix switch and just do indent := strings.Repeat(" ", lipgloss.Width(prefix)) inline, then either inline-delete annotationContinuationIndent or have it take prefix directly.

2. no newline/control-char validation on --annotation-marker. A \n/\r/\t in REVDIFF_ANNOTATION_MARKER (config file or env) would break layout silently. Nit, worst case is the user breaks their own rendering, but a strings.ContainsAny(marker, "\n\r\t") check at parse time with a clear error costs nothing.

re #5 (the empty-marker assertion): the assert.NotContains(rendered, "💬") you added catches a hardcoded emoji fallback regression, which was the actual worry. Fine as-is.

[jknlsn]

Added fixes and tests for those copilot catches, thanks!

[umputun]

lgtm, thx