t3/try pierre diff improvements

apps/web/src/components/DiffPanel.tsx

@@ -776,12 +776,12 @@ export default function DiffPanel({
       return next;
     });
   });
-  // Find can ask again before the unfolded file reaches the viewer, so this must never fold.
-  const unfoldDiffFile = useStableCallback((fileKey: string) => {
+  const setDiffFileCollapsed = useStableCallback((fileKey: string, collapsed: boolean) => {
     updateCollapsedDiffFiles((current) => {
-      if (!current.has(fileKey)) return current;
+      if (current.has(fileKey) === collapsed) return current;
       const next = new Set(current);
-      next.delete(fileKey);
+      if (collapsed) next.add(fileKey);
+      else next.delete(fileKey);
       return next;
     });
   });
@@ -1458,7 +1458,7 @@ export default function DiffPanel({
                           },
                         }
                       : {})}
-                    onRevealSearchMatch={unfoldDiffFile}
+                    onFileCollapsedChange={setDiffFileCollapsed}
                     renderHeaderPrefix={(fileDiff, fileKey, collapsed) => {
                       return (
                         <DiffFileCollapseToggle

apps/web/src/components/diffs/AnnotatableCodeView.browser.test.tsx

@@ -92,7 +92,7 @@ function view(
         options={{}}
         renderHeaderFilenameSuffix={() => null}
         renderHeaderPrefix={() => null}
-        onRevealSearchMatch={() => {}}
+        onFileCollapsedChange={() => {}}
       />
     </StrictMode>
   );

apps/web/src/components/diffs/AnnotatableCodeView.tsx

@@ -99,7 +99,7 @@ interface AnnotatableCodeViewProps {
     fileKey: string,
     collapsed: boolean,
   ) => ReactNode;
-  onRevealSearchMatch: (fileKey: string) => void;
+  onFileCollapsedChange: (fileKey: string, collapsed: boolean) => void;
 }
 
 interface DiffSelectionContext {
@@ -124,7 +124,7 @@ export function AnnotatableCodeView({
   renderHeaderMetadata,
   renderHeaderFilenameSuffix,
   renderHeaderPrefix,
-  onRevealSearchMatch,
+  onFileCollapsedChange,
 }: AnnotatableCodeViewProps) {
   const addReviewComment = useComposerDraftStore((store) => store.addReviewComment);
   const removeReviewComment = useComposerDraftStore((store) => store.removeReviewComment);
@@ -280,7 +280,8 @@ export function AnnotatableCodeView({
         enableGutterUtility: draft === null,
         enableLineSelection: draft === null,
         onGutterUtilityClick: beginComment,
-        onRevealSearchMatch: (item) => onRevealSearchMatch(item.id),
+        onItemCollapsedChange: (_item, nextItem) =>
+          onFileCollapsedChange(nextItem.id, nextItem.collapsed === true),
       }}
       renderHeaderFilenameSuffix={(item) =>
         item.type === "diff" ? renderHeaderFilenameSuffix(item.fileDiff) : null

apps/web/src/components/pullRequest/PullRequestCodeTab.tsx

@@ -1036,9 +1036,13 @@ function PullRequestCodeTab({
     onGutterUtilityClick: beginComment,
     onLineSelectionEnd: beginComment,
     onPostRender: codeViewReveal.flush,
-    // Find may repeat requests before render; only unfold, never toggle.
-    onRevealSearchMatch: (item: CodeViewItem<ReviewAnnotationGroup>) =>
-      setFoldChoices((current) => withFileDiffFold(current, item.id, false)),
+    onItemCollapsedChange: (
+      _item: CodeViewItem<ReviewAnnotationGroup>,
+      nextItem: CodeViewItem<ReviewAnnotationGroup>,
+    ) =>
+      setFoldChoices((current) =>
+        withFileDiffFold(current, nextItem.id, nextItem.collapsed === true),
+      ),
   };
 
   const runThreadCommand = async (