fix: reject oversized checkout diffs (#2488)

* fix: reject oversized checkout diffs

* fix(diff): keep large previews from disconnecting clients

The physical socket limit is an OOM backstop, not a frame-size contract. Bound structured diff construction incrementally and report oversized previews without closing the client's socket.

* fix(app): preserve oversized diff state

* fix(diff): stay within relay frame limit

---------

Co-authored-by: Mohamed Boudra <boudra.moha@gmail.com>

packages/app/src/data/push-router.test.ts

@@ -204,25 +204,34 @@ describe("server data push router", () => {
 
     fake.emit({
       type: "subscribe_checkout_diff_response",
-      payload: { subscriptionId, cwd, files: [], error: null, requestId: "diff-1" },
+      payload: {
+        subscriptionId,
+        cwd,
+        files: [],
+        error: null,
+        diffTooLarge: true,
+        requestId: "diff-1",
+      },
     });
 
     expect(queryClient.getQueryData(queryKey)).toEqual({
       cwd,
       files: [],
       error: null,
+      diffTooLarge: true,
       requestId: "diff-1",
     });
 
     fake.emit({
       type: "checkout_diff_update",
-      payload: { subscriptionId, cwd, files: [], error: null },
+      payload: { subscriptionId, cwd, files: [], error: null, diffTooLarge: true },
     });
 
     expect(queryClient.getQueryData(queryKey)).toEqual({
       cwd,
       files: [],
       error: null,
+      diffTooLarge: true,
       requestId: `subscription:${subscriptionId}`,
     });
 

packages/app/src/data/push-router.ts

@@ -420,6 +420,9 @@ function applyCheckoutDiffUpdate(input: {
       cwd: input.message.payload.cwd,
       files: orderCheckoutDiffFiles(input.message.payload.files),
       error: input.message.payload.error,
+      ...(input.message.payload.diffTooLarge !== undefined
+        ? { diffTooLarge: input.message.payload.diffTooLarge }
+        : {}),
       requestId: `subscription:${input.message.payload.subscriptionId}`,
     },
   });
@@ -440,6 +443,9 @@ function applyCheckoutDiffSubscribeResponse(input: {
       cwd: input.message.payload.cwd,
       files: orderCheckoutDiffFiles(input.message.payload.files),
       error: input.message.payload.error,
+      ...(input.message.payload.diffTooLarge !== undefined
+        ? { diffTooLarge: input.message.payload.diffTooLarge }
+        : {}),
       requestId: input.message.payload.requestId,
     },
   });

packages/app/src/git/diff-pane.tsx

@@ -119,6 +119,7 @@ import {
   type InlineReviewActions,
 } from "@/review";
 import { usePublishWorkingDiffAttachment, useWorkingDiff } from "@/git/use-working-diff";
+import { DiffTooLargeState } from "@/git/diff-too-large-state";
 
 export type { GitActionId, GitAction, GitActions } from "@/git/policy";
 
@@ -1755,6 +1756,7 @@ interface DiffBodyContentProps {
   notGit: boolean;
   isDiffLoading: boolean;
   diffErrorMessage: string | null;
+  diffTooLarge: boolean;
   hasChanges: boolean;
   emptyMessage: string;
   children: ReactElement;
@@ -1768,6 +1770,7 @@ function DiffBodyContent({
   notGit,
   isDiffLoading,
   diffErrorMessage,
+  diffTooLarge,
   hasChanges,
   emptyMessage,
   children,
@@ -1803,6 +1806,9 @@ function DiffBodyContent({
       </View>
     );
   }
+  if (diffTooLarge) {
+    return <DiffTooLargeState />;
+  }
   if (diffErrorMessage) {
     return (
       <View style={styles.errorContainer}>
@@ -2693,6 +2699,7 @@ export function GitDiffPane({
     selectBase: handleSelectBase,
     files,
     diffPayloadError,
+    diffTooLarge,
     isDiffLoading,
     reviewActions,
     reviewAttachment,
@@ -2855,6 +2862,7 @@ export function GitDiffPane({
       notGit={notGit}
       isDiffLoading={isDiffLoading}
       diffErrorMessage={diffErrorMessage}
+      diffTooLarge={diffTooLarge}
       hasChanges={hasChanges}
       emptyMessage={emptyMessage}
       checkingRepositoryLabel={t("workspace.git.diff.checkingRepository")}

packages/app/src/git/diff-too-large-state.tsx

@@ -0,0 +1,49 @@
+import { useTranslation } from "react-i18next";
+import { Text, View } from "react-native";
+import { FileWarning } from "lucide-react-native";
+import { StyleSheet, withUnistyles } from "react-native-unistyles";
+import { ICON_SIZE, type Theme } from "@/styles/theme";
+
+const ThemedFileWarning = withUnistyles(FileWarning);
+const foregroundMutedIconColorMapping = (theme: Theme) => ({ color: theme.colors.foregroundMuted });
+
+export function DiffTooLargeState() {
+  const { t } = useTranslation();
+
+  return (
+    <View style={styles.container} testID="diff-too-large">
+      <ThemedFileWarning size={ICON_SIZE.lg} uniProps={foregroundMutedIconColorMapping} />
+      <View style={styles.copy}>
+        <Text style={styles.title}>{t("workspace.git.diff.previewTooLargeTitle")}</Text>
+        <Text style={styles.description}>{t("workspace.git.diff.previewTooLargeDescription")}</Text>
+      </View>
+    </View>
+  );
+}
+
+const styles = StyleSheet.create((theme) => ({
+  container: {
+    flex: 1,
+    alignItems: "center",
+    justifyContent: "center",
+    gap: theme.spacing[3],
+    paddingHorizontal: theme.spacing[6],
+    paddingTop: theme.spacing[16],
+  },
+  copy: {
+    alignItems: "center",
+    gap: theme.spacing[1],
+    maxWidth: 360,
+  },
+  title: {
+    color: theme.colors.foreground,
+    fontSize: theme.fontSize.base,
+    fontWeight: theme.fontWeight.normal,
+    textAlign: "center",
+  },
+  description: {
+    color: theme.colors.foregroundMuted,
+    fontSize: theme.fontSize.xs,
+    textAlign: "center",
+  },
+}));

packages/app/src/git/use-diff-query.ts

@@ -92,6 +92,7 @@ export function useCheckoutDiffQuery({
   return {
     files: payload?.files ?? [],
     payloadError,
+    diffTooLarge: payload?.diffTooLarge === true,
     isLoading: payload === null && enabled && isConnected,
     isFetching: false,
     isError: Boolean(payloadError),

packages/app/src/git/use-working-diff.ts

@@ -79,6 +79,7 @@ export function useWorkingDiff({
   const {
     files,
     payloadError: diffPayloadError,
+    diffTooLarge,
     isLoading: isDiffLoading,
   } = useCheckoutDiffQuery({
     serverId,
@@ -123,6 +124,7 @@ export function useWorkingDiff({
     selectBase,
     files,
     diffPayloadError,
+    diffTooLarge,
     isDiffLoading,
     reviewActions,
     reviewAttachment,

packages/app/src/i18n/resources/ar.ts

@@ -764,6 +764,8 @@ export const ar: TranslationResources = {
         closeChangesTab: "إغلاق علامة تبويب التغييرات",
         binaryFile: "ملف ثنائي",
         tooLarge: "الفرق كبير جدًا بحيث لا يمكن عرضه",
+        previewTooLargeTitle: "هذا الفرق كبير جدًا بحيث لا يمكن معاينته",
+        previewTooLargeDescription: "ضيّق نطاق المقارنة لمعاينتها هنا",
         unified: "الفرق الموحدة",
         split: "فرق جنبًا إلى جنب",
         switchToUnified: "التبديل إلى الفرق الموحد",

packages/app/src/i18n/resources/en.ts

@@ -774,6 +774,8 @@ export const en = {
         closeChangesTab: "Close Changes tab",
         binaryFile: "Binary file",
         tooLarge: "Diff too large to display",
+        previewTooLargeTitle: "This diff is too large to preview",
+        previewTooLargeDescription: "Narrow the comparison to preview it here",
         unified: "Unified diff",
         split: "Side-by-side diff",
         switchToUnified: "Switch to unified diff",

packages/app/src/i18n/resources/es.ts

@@ -795,6 +795,8 @@ export const es: TranslationResources = {
         closeChangesTab: "Cerrar la pestaña Cambios",
         binaryFile: "archivo binario",
         tooLarge: "La diferencia es demasiado grande para mostrarse",
+        previewTooLargeTitle: "Este diff es demasiado grande para previsualizarlo",
+        previewTooLargeDescription: "Reduce la comparación para previsualizarla aquí",
         unified: "Diferencia unificada",
         split: "Diferencia de lado a lado",
         switchToUnified: "Cambiar a diferencia unificada",

packages/app/src/i18n/resources/fr.ts

@@ -794,6 +794,8 @@ export const fr: TranslationResources = {
         closeChangesTab: "Fermer l'onglet Modifications",
         binaryFile: "Fichier binaire",
         tooLarge: "Diff trop grand pour être affiché",
+        previewTooLargeTitle: "Ce diff est trop volumineux pour être prévisualisé",
+        previewTooLargeDescription: "Réduisez la comparaison pour la prévisualiser ici",
         unified: "Différentiel unifié",
         split: "Différent côte à côte",
         switchToUnified: "Passer au diff unifié",

packages/app/src/i18n/resources/ja.ts

@@ -775,6 +775,8 @@ export const ja: TranslationResources = {
         closeChangesTab: "変更タブを閉じる",
         binaryFile: "バイナリファイル",
         tooLarge: "差分が大きすぎて表示できません",
+        previewTooLargeTitle: "この差分は大きすぎるためプレビューできません",
+        previewTooLargeDescription: "比較範囲を狭めると、ここでプレビューできます",
         unified: "ユニファイド差分",
         split: "左右比較",
         switchToUnified: "ユニファイド差分に切り替え",

packages/app/src/i18n/resources/pt-BR.ts

@@ -786,6 +786,8 @@ export const ptBR: TranslationResources = {
         closeChangesTab: "Fechar a aba Alterações",
         binaryFile: "Arquivo binário",
         tooLarge: "Diff grande demais para exibir",
+        previewTooLargeTitle: "Este diff é grande demais para visualizar",
+        previewTooLargeDescription: "Reduza a comparação para visualizá-la aqui",
         unified: "Diff unificado",
         split: "Diff lado a lado",
         switchToUnified: "Alternar para diff unificado",

packages/app/src/i18n/resources/ru.ts

@@ -786,6 +786,8 @@ export const ru: TranslationResources = {
         closeChangesTab: "Закрыть вкладку «Изменения»",
         binaryFile: "Бинарный файл",
         tooLarge: "Разница слишком велика для отображения",
+        previewTooLargeTitle: "Этот diff слишком велик для предпросмотра",
+        previewTooLargeDescription: "Сузьте сравнение, чтобы просмотреть его здесь",
         unified: "Единый дифференциал",
         split: "Параллельная разница",
         switchToUnified: "Переключить на объединенный diff",

packages/app/src/i18n/resources/zh-CN.ts

@@ -756,6 +756,8 @@ export const zhCN: TranslationResources = {
         closeChangesTab: "关闭“更改”标签页",
         binaryFile: "二进制文件",
         tooLarge: "Diff 过大，无法显示",
+        previewTooLargeTitle: "此 diff 过大，无法预览",
+        previewTooLargeDescription: "缩小比较范围即可在此预览",
         unified: "Unified diff",
         split: "Side-by-side diff",
         switchToUnified: "切换到统一差异视图",

packages/app/src/panels/diff-panel.tsx

@@ -17,6 +17,7 @@ import {
   resolveDiffLayout,
   SharedDiffView,
 } from "@/git/diff-pane";
+import { DiffTooLargeState } from "@/git/diff-too-large-state";
 import { useCommitDiffFiles } from "@/git/use-diff-files";
 import { usePublishWorkingDiffAttachment, useWorkingDiff } from "@/git/use-working-diff";
 import { useChangesPreferences } from "@/hooks/use-changes-preferences";
@@ -120,6 +121,9 @@ function WorkingDiffBody({
   if (workingDiff.notGit) {
     return <PanelState message={t("workspace.git.diff.notRepository")} />;
   }
+  if (workingDiff.diffTooLarge) {
+    return <DiffTooLargeState />;
+  }
   if (workingDiff.diffPayloadError) {
     return (
       <PanelState message={t("panels.diff.loadError")} tone="error" testID="working-diff-error" />