Diff Viewer

The Diff Viewer renders file-level differences with syntax highlighting, inline annotations, and interactive controls. It appears in multiple contexts throughout the application — the Changes view, commit detail, PR review, and standalone file comparison.

Where Diffs Appear

Features

Unified Diff

The default view shows additions and deletions inline:

  fn main() {
-     println!("Hello, world!");
+     println!("Hello, Crab!");
+     init_logging();
  }

• Deletions highlighted in red
• Additions highlighted in green
• Unchanged context lines in default color
• Line numbers for both old and new versions

Split (Side-by-Side) Diff

Toggle to split view for easier comparison of large changes. The old version appears on the left and the new version on the right, with changes highlighted inline.

Configurable in Settings → Diff → Diff Style.

Syntax Highlighting

Diffs are syntax-highlighted using Shiki grammars:

• Language detected from file extension
• Highlighting applied to both old and new content
• Themes match the editor theme setting
• Grammars loaded lazily and cached

Hunk Navigation

Navigate between change regions:

• Next hunk: ]c or toolbar button
• Previous hunk: [c or toolbar button
• Hunk boundaries are visually marked with a separator line

Expand Context

Click "Show N more lines" between hunks to reveal additional context without loading the entire file.

Word-Level Diff

Within changed lines, individual word changes are highlighted:

• Deleted words: red background
• Added words: green background
• Helps identify small changes within long lines

Configurable in Settings → Diff → Word Diff.

Whitespace Handling

Options for whitespace display:

• Show all — spaces, tabs, and line endings visible
• Ignore whitespace — hide whitespace-only changes
• Trim trailing — ignore trailing whitespace differences

Patch Minimap

A minimap on the right edge shows the overall shape of the diff:

• Red marks for deletions
• Green marks for additions
• Click to jump to a specific region
• Useful for navigating large diffs

Inline Comments (PR Review)

When viewing PR diffs, inline comments appear in the gutter:

• Click the gutter to add a new comment
• Existing comments show as expandable annotations
• Reply to threads inline
• Resolve conversations

Notebook Diffs

For Jupyter notebook files (.ipynb), a specialized diff view shows:

• Cell-level changes (not raw JSON)
• Markdown cells rendered
• Code cells with syntax highlighting
• Output changes (images, tables)

Crab Pointer Diffs

When a Crab pointer file changes, the diff shows:

• Pointer metadata comparison (hash, size)
• Chunk-level diff (which chunks changed)
• Option to view the full content diff (requires hydration)

Hunk Staging Controls

In the Changes view, each hunk has interactive controls:

These controls appear on hover over the hunk header.

Keyboard Shortcuts

Performance

• Diffs are fetched on demand (not pre-loaded for all files)
• Large diffs (> 10,000 lines) show a warning with option to load
• Syntax highlighting is async (doesn't block initial render)
• Monaco editor handles scrolling for very large files
• Cancellable: switching files cancels the in-flight diff fetch