Add expandUnchanged setting to show full files in diffs

README.md

@@ -179,6 +179,8 @@ Choose `View > Diff > Split` or `View > Diff > Unified`, use Toggle Diff Layout
 or set `settings.diffStyle` to `split` for side-by-side diffs or `unified` for unified diffs.
 Choose `View > Diff > Word Wrap`, use Toggle Word Wrap in the command bar, or set
 `settings.wordWrap` to `true` to wrap long diff lines.
+Choose `View > Diff > Expand Unchanged Lines` or set `settings.expandUnchanged` to `true` to show
+full files instead of collapsing unchanged lines between hunks.
 Choose `View > Diff > Font Size`, use the code font size commands in the command bar, or use
 <kbd>Cmd/Ctrl</kbd>+<kbd>+</kbd>, <kbd>Cmd/Ctrl</kbd>+<kbd>-</kbd>, and
 <kbd>Cmd/Ctrl</kbd>+<kbd>0</kbd> to change only diff and code rendering font size.

config/defaults.json

@@ -8,6 +8,7 @@
     "copyCommentsOnClose": false,
     "diffStyle": "split",
     "editorCommand": "",
+    "expandUnchanged": false,
     "lastRepositoryPath": "",
     "openAIModel": "gpt-5.6-terra",
     "opencodeModel": "opencode-default",

core/App.tsx

@@ -1754,6 +1754,7 @@ export default function App() {
     diffStyle,
     disableWorkerPool: disableCodeViewWorkerPool,
     expandedReviewKeys,
+    expandUnchanged: preferences.expandUnchanged,
     focusCommentId,
     focusCommentRequest,
     gitIdentity,

core/__tests__/App-render.test.tsx

@@ -181,6 +181,7 @@ const createCodiffMock = (overrides: Partial<Window['codiff']> = {}): Window['co
     copyCommentsOnClose: true,
     diffStyle: 'split' as const,
     editorCommand: '',
+    expandUnchanged: false,
     lastRepositoryPath: '/repo',
     openAIModel: defaultSettings.openAIModel,
     opencodeModel: defaultSettings.opencodeModel,

core/__tests__/ReviewCodeView-header.test.tsx

@@ -249,3 +249,21 @@ test('narrow pane layout and sticky header metrics resize together without losin
   expect(codeViewMock.lastOptions?.itemMetrics).toEqual({ diffHeaderHeight: 54 });
   expect(viewport.style.getPropertyValue('--codiff-file-header-height')).toBe('54px');
 });
+
+test('expandUnchanged only expands diffs when full file contents can be loaded', async () => {
+  const loadContents = vi.fn();
+  await using view = await renderReact(
+    <ReviewCodeViewHarness expandUnchanged files={[file]} onLoadSectionContents={loadContents} />,
+  );
+  expect(codeViewMock.lastOptions?.expandUnchanged).toBe(true);
+
+  await view.rerender(
+    <ReviewCodeViewHarness
+      expandUnchanged
+      files={[file]}
+      isReadOnly
+      onLoadSectionContents={loadContents}
+    />,
+  );
+  expect(codeViewMock.lastOptions?.expandUnchanged).toBe(false);
+});

core/app/components/ReviewCodeView.tsx

@@ -2618,6 +2618,7 @@ export function ReviewCodeView({
   diffStyle,
   disableWorkerPool = false,
   expandedReviewKeys = emptyExpandedReviewKeys,
+  expandUnchanged = false,
   files,
   focusCommentId,
   focusCommentRequest,
@@ -2681,6 +2682,7 @@ export function ReviewCodeView({
   diffStyle: CodiffDiffStyle;
   disableWorkerPool?: boolean;
   expandedReviewKeys?: ReadonlySet<string>;
+  expandUnchanged?: boolean;
   files: ReadonlyArray<ChangedFile>;
   focusCommentId: string | null;
   focusCommentRequest: number;
@@ -3625,7 +3627,7 @@ export function ReviewCodeView({
         diffStyle,
         enableGutterUtility: !isReadOnly,
         enableLineSelection: !isReadOnly,
-        expandUnchanged: false,
+        expandUnchanged: expandUnchanged && loadDiffFiles != null,
         expansionLineCount: diffContextExpansionLineCount,
         hunkSeparators: 'line-info-basic',
         itemMetrics,
@@ -3805,6 +3807,7 @@ export function ReviewCodeView({
       cancelPendingEmptyCommentDeletes,
       createCommentForRange,
       diffStyle,
+      expandUnchanged,
       isReadOnly,
       itemMetadata,
       itemMetrics,

core/config/codiff-config.schema.json

@@ -58,6 +58,11 @@
           "default": "",
           "description": "Command used to open files from Codiff. Use {file} as the file path placeholder, {line} as the optional line number, and {repo} as the repository root placeholder, for example \"subl \\\"{repo}\\\" \\\"{file}\\\"\", or leave empty to use Codiff's default editor lookup."
         },
+        "expandUnchanged": {
+          "type": "boolean",
+          "default": false,
+          "description": "Show full files in diffs instead of collapsing unchanged lines between hunks."
+        },
         "lastRepositoryPath": {
           "type": "string",
           "default": "",

core/config/types.ts

@@ -11,6 +11,7 @@ export type CodiffSettings = {
   copyCommentsOnClose: boolean;
   diffStyle: CodiffDiffStyle;
   editorCommand: string;
+  expandUnchanged: boolean;
   lastRepositoryPath: string;
   openAIModel: string;
   opencodeModel: string;

core/types.ts

@@ -799,6 +799,7 @@ export type CodiffPreferences = {
   copyCommentsOnClose: boolean;
   diffStyle: CodiffDiffStyle;
   editorCommand: string;
+  expandUnchanged: boolean;
   lastRepositoryPath: string;
   openAIModel: string;
   opencodeModel: string;

electron/config.cjs

@@ -300,6 +300,10 @@ const mergeConfig = (raw) => {
         typeof rawSettings.editorCommand === 'string'
           ? rawSettings.editorCommand
           : defaults.settings.editorCommand,
+      expandUnchanged:
+        typeof rawSettings.expandUnchanged === 'boolean'
+          ? rawSettings.expandUnchanged
+          : defaults.settings.expandUnchanged,
       lastRepositoryPath: normalizeLastRepositoryPath(rawSettings.lastRepositoryPath),
       openAIModel:
         typeof rawSettings.openAIModel === 'string'

electron/main.cjs

@@ -757,6 +757,16 @@ const buildApplicationMenu = () =>
                 label: 'Show Whitespace',
                 type: 'checkbox',
               },
+              {
+                checked: config.settings.expandUnchanged,
+                click: (menuItem) => {
+                  updateConfig({
+                    settings: { ...config.settings, expandUnchanged: menuItem.checked },
+                  });
+                },
+                label: 'Expand Unchanged Lines',
+                type: 'checkbox',
+              },
               { type: 'separator' },
               {
                 label: 'Font Size',