* feat(vcs): IDEA's diff algorithm and change colouring in the diff viewer Port IntelliJ's text comparison to TypeScript (src/features/vcs/comparison): Myers/patience LCS with unique-element discarding, ByLine (smart matching that skips unimportant lines, chunk optimizer, second-step correction), ByWord (word chunks, punctuation matching, whitespace policies, line block splitting) and ComparisonManager's compareLinesInner / processBlocks. The port runs IntelliJ's own LineComparisonUtilTest, WordComparisonUtilTest and SplitComparisonUtilTest cases (459 runs), converted to ideaCases.json. MergeView chunks now come straight from these line fragments, with the inner word fragments as chunk changes, instead of @codemirror/merge's presentable diff. Revert and >> / << replace lines as DiffUtil.applyModification does. Colour changes as IDEA does: modified (blue), inserted (green) and deleted (grey) by chunk type, a lighter line background for chunks whose words were compared, each word fragment in its own type at full line height, a thin bar for a fragment empty on one side, and the colours carried into the gutters and the divider bands. New --diff-modified / --diff-inserted / --diff-deleted theme tokens, imported from .icls DIFF_* attributes. Add a Playwright suite over a generated git repository of diff cases, including 10,000-line files, in every viewer mode. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com> * fix(vcs): preserve unified revert boundaries and bound large diffs --------- Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com> Co-authored-by: l0ng-ai <24760907+l0ng-ai@users.noreply.github.com>
Theme plugin template
A complete OpenIDEA theme plugin with one worked example, Harbor Night: a
dark theme with slate surfaces, a teal accent and a warm syntax palette. Copy
this folder to start your own theme. Full documentation, the token reference
and porting guides are in docs/plugins/themes.md.
theme-plugin/
├─ plugin.toml # manifest: id, name, version, the theme files
└─ themes/
├─ harbor-night.theme.json # UI colours, every themeable token, grouped like tokens.css
└─ harbor-night.scheme.json # editor colour scheme: syntax, editor, ANSI colours
A theme plugin is data only: no code, no WebAssembly, no build step.
Make your own
- Copy the folder, for example to
~/openidea-themes/theme-my-theme. - In
plugin.toml, changeid(lowercase,a-z 0-9 - _),name,description,authorsand the two paths. - Rename the theme files. In the theme file, set
id,nameandkind("dark"or"light", the built-in base for anything you leave out). - Edit the colours. Each key is a CSS variable from
src/styles/tokens.css, and the reference in the docs gives the Islands Dark and Light values. Comments (//,/* */) are allowed. Delete a line to keep the built-in value.
Porting an IntelliJ theme? pnpm theme:import-intellij <file.theme.json> [file.icls] --out <dir>
in the OpenIDEA repository generates a package in this layout.
Package and install
The folder is the package. To share it, publish the folder as a Git repository or a zip that users extract.
- In OpenIDEA open Settings › Plugins, click the gear menu and choose
Install Plugin from Disk… (or run the Install Plugin from Disk…
action), then pick the folder that contains
plugin.toml. - Select the plugin in the Installed tab and press Apply next to the theme.
- Use Default Theme in the same place goes back to the built-in theme.
Iterate
Put (or symlink) the folder in <project>/.openidea/plugins/ of an open
project. It loads as a dev plugin, and Reload in Settings › Plugins (or
the Reload Plugins action) re-reads your edits without reinstalling. Invalid
JSON or values are reported in Settings › Plugins with the file and line.
Licence
The template and Harbor Night are part of OpenIDEA (Apache-2.0). When you port someone else's theme, keep its licence and credit its authors.