[stacked] Add single side-aware rail rendering #156

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opened 2026-09-21 18:12:36 +00:00 by barrettruth · 0 comments

barrettruth commented

2026-09-21 18:12:36 +00:00

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Original issue: barrettruth/diffs.nvim#362
Original author: barrettruth
Original date: 2026-05-28T02:57:34Z

Part of #358.

Goal

Add an internal single side-aware generated rail style while preserving current dual old/new rails by default.

Scope

Extend rails.annotate() with an internal rail_style = 'dual'|'single' option.
Keep dual as the default and preserve existing output exactly.
Implement single rail line-number semantics:
- deleted lines show old-side line numbers;
- added lines show new-side line numbers;
- context lines show new-side line numbers;
- file headers, hunk headers, and metadata rows show no file line number.
Return rail metadata that identifies the rendered style, for example RailInfo.style.
Add style-aware rail number range helpers for highlighting rather than forcing the current dual-only range shape to represent single rails.
Keep custom view.rail_separator behavior, including empty string support.
Preserve empty context line stripping behavior.

Non-goals

Do not wire ++layout=stacked into commands yet.
Do not add public config.
Do not change split endpoint windows.

Acceptance criteria

Default generated buffers keep the existing dual rail behavior.
rails.annotate(lines, { rail_style = 'single' }) produces a narrower single side-aware rail.
Single rail metadata reports the correct prefix and separator widths.
rails.strip() and rails.strip_lines() recover raw unified diff text from single-rail display lines.
Custom rail separators work with single rails.

> Original issue: barrettruth/diffs.nvim#362 > Original author: `barrettruth` > Original date: 2026-05-28T02:57:34Z Part of #358. ## Goal Add an internal single side-aware generated rail style while preserving current dual old/new rails by default. ## Scope - Extend `rails.annotate()` with an internal `rail_style = 'dual'|'single'` option. - Keep `dual` as the default and preserve existing output exactly. - Implement single rail line-number semantics: - deleted lines show old-side line numbers; - added lines show new-side line numbers; - context lines show new-side line numbers; - file headers, hunk headers, and metadata rows show no file line number. - Return rail metadata that identifies the rendered style, for example `RailInfo.style`. - Add style-aware rail number range helpers for highlighting rather than forcing the current dual-only range shape to represent single rails. - Keep custom `view.rail_separator` behavior, including empty string support. - Preserve empty context line stripping behavior. ## Non-goals - Do not wire `++layout=stacked` into commands yet. - Do not add public config. - Do not change split endpoint windows. ## Acceptance criteria - Default generated buffers keep the existing dual rail behavior. - `rails.annotate(lines, { rail_style = 'single' })` produces a narrower single side-aware rail. - Single rail metadata reports the correct prefix and separator widths. - `rails.strip()` and `rails.strip_lines()` recover raw unified diff text from single-rail display lines. - Custom rail separators work with single rails.

barrettruth

2026-09-21 18:12:36 +00:00