refactor(review): keep gap toggle selection in controller

Author: adit-chandra

src/ui/App.tsx

@@ -18,8 +18,6 @@ import {
   maxFileCodeLineWidth,
   resolveCodeViewportWidth,
 } from "./diff/codeColumns";
-import { selectGapForKeyboardToggle } from "./diff/expandCollapsedRows";
-import { trailingCollapsedLines } from "./diff/pierre";
 import { useAppKeyboardShortcuts } from "./hooks/useAppKeyboardShortcuts";
 import { useHunkSessionBridge } from "./hooks/useHunkSessionBridge";
 import { useMenuController } from "./hooks/useMenuController";
@@ -337,24 +335,6 @@ export function App({
     [review.selectHunk],
   );
 
-  /** Toggle the leading gap of the selected hunk, scanning forward to the next
-   *  available gap (or the trailing gap) when nothing is reachable above. */
-  const toggleGapForSelectedHunk = useCallback(() => {
-    const file = selectedFile;
-    if (!file?.sourceFetcher) {
-      return;
-    }
-
-    const target = selectGapForKeyboardToggle(
-      file.metadata.hunks,
-      selectedHunkIndex,
-      trailingCollapsedLines(file.metadata) > 0,
-    );
-    if (target) {
-      review.toggleGap(file.id, target);
-    }
-  }, [review, selectedFile, selectedHunkIndex]);
-
   const canRefreshCurrentInput = canReloadInput(bootstrap.input);
   const watchEnabled = Boolean(bootstrap.input.options.watch && canRefreshCurrentInput);
 
@@ -582,7 +562,7 @@ export function App({
     switchMenu,
     toggleAgentNotes,
     toggleFocusArea,
-    toggleGapForSelectedHunk,
+    toggleGapForSelectedHunk: review.toggleSelectedHunkGap,
     toggleHelp,
     toggleHunkHeaders,
     toggleLineNumbers,

src/ui/hooks/useReviewController.test.tsx

@@ -438,6 +438,41 @@ describe("useReviewController", () => {
     }
   });
 
+  test("toggleSelectedHunkGap expands the nearest gap for the current selection", async () => {
+    const beforeLines = Array.from({ length: 30 }, (_, index) => `line ${index + 1}`);
+    const afterLines = [...beforeLines];
+    afterLines[4] = "line 5 changed";
+    const after = lines(...afterLines);
+    const sourceFetcher = createTestSourceFetcher((side) => (side === "new" ? after : null));
+    const file = createTestDiffFile({
+      after,
+      before: lines(...beforeLines),
+      context: 3,
+      id: "alpha",
+      path: "alpha.ts",
+      sourceFetcher,
+    });
+
+    const { controllerRef, setup } = await renderReviewController([file]);
+
+    try {
+      await flush(setup);
+
+      await act(async () => {
+        expectValue(controllerRef.current).toggleSelectedHunkGap();
+      });
+      await flush(setup);
+
+      const expanded = expectValue(controllerRef.current).expandedGapsByFileId["alpha"];
+      expect(expanded?.has("before:0")).toBe(true);
+      expect(sourceFetcher.calls).toEqual(["new"]);
+    } finally {
+      await act(async () => {
+        setup.renderer.destroy();
+      });
+    }
+  });
+
   test("toggleGap surfaces an error status when the fetcher resolves null", async () => {
     const failingFetcher = createTestSourceFetcher(() => null);
 

src/ui/hooks/useReviewController.ts

@@ -34,6 +34,8 @@ import type {
   SessionLiveCommentSummary,
 } from "../../hunk-session/types";
 import type { FileSourceStatus } from "../diff/expandCollapsedRows";
+import { selectGapForKeyboardToggle } from "../diff/expandCollapsedRows";
+import { trailingCollapsedLines } from "../diff/pierre";
 import { findNextHunkCursor } from "../lib/hunks";
 import {
   buildReviewState,
@@ -94,6 +96,7 @@ export interface ReviewController {
   sidebarEntries: ReviewState["sidebarEntries"];
   sourceStatusByFileId: Record<string, FileSourceStatus>;
   toggleGap: (fileId: string, gapKey: string) => void;
+  toggleSelectedHunkGap: () => void;
   visibleFiles: DiffFile[];
   addLiveComment: (
     input: CommentToolInput,
@@ -404,6 +407,23 @@ export function useReviewController({ files }: { files: DiffFile[] }): ReviewCon
     [allFiles],
   );
 
+  /** Toggle the collapsed gap nearest to the current hunk selection. */
+  const toggleSelectedHunkGap = useCallback(() => {
+    const file = selectedFile;
+    if (!file?.sourceFetcher) {
+      return;
+    }
+
+    const target = selectGapForKeyboardToggle(
+      file.metadata.hunks,
+      selectedHunkIndex,
+      trailingCollapsedLines(file.metadata) > 0,
+    );
+    if (target) {
+      toggleGap(file.id, target);
+    }
+  }, [selectedFile, selectedHunkIndex, toggleGap]);
+
   /** Resolve one session-daemon navigation request against the current review state and select it. */
   const navigateToLocation = useCallback(
     (input: NavigateToHunkToolInput): NavigatedSelectionResult => {
@@ -652,6 +672,7 @@ export function useReviewController({ files }: { files: DiffFile[] }): ReviewCon
     sidebarEntries,
     sourceStatusByFileId,
     toggleGap,
+    toggleSelectedHunkGap,
     visibleFiles,
     addLiveComment,
     addLiveCommentBatch,