fix(server): bound untracked files before review diffs

apps/mobile/src/features/review/ReviewSheet.tsx

@@ -6,7 +6,7 @@ import { useNavigation, type StaticScreenProps } from "@react-navigation/native"
 import { AppActivityIndicator } from "../../components/ui/AppActivityIndicator";
 import { AppBar } from "../../components/ui/AppBar";
 import type { AppBarMenuItem } from "../../components/ui/AppBar.types";
-import type { ReviewSectionItem } from "./reviewModel";
+import { UNTRACKED_OMITTED_NOTICE, type ReviewSectionItem } from "./reviewModel";
 import { useReviewHeaderPresentation } from "./useReviewHeaderPresentation";
 import { type Ref, type ReactElement, useImperativeHandle, useRef, useState } from "react";
 import {
@@ -766,7 +766,9 @@ export function ReviewSheet(props: ReviewSheetProps) {
                       Platform.OS === "android" && "mt-2 text-center",
                     )}
                   >
-                    {selectedSection.subtitle ?? "This diff is empty."}
+                    {selectedSection.source?.untrackedOmitted
+                      ? UNTRACKED_OMITTED_NOTICE
+                      : (selectedSection.subtitle ?? "This diff is empty.")}
                   </Text>
                 </View>
               ) : parsedDiff.kind === "raw" ? (

apps/mobile/src/features/review/reviewModel.ts

@@ -664,14 +664,20 @@ export function buildReviewParsedDiff(
   }
 }
 
+export const UNTRACKED_OMITTED_NOTICE =
+  "Some untracked files are too large to review. They are not shown or counted.";
+
 export function applyReviewDiffMetadata(
   previewDiff: ReviewParsedDiff,
-  selectedSection: Pick<ReviewSectionItem, "files" | "truncated"> | null,
+  selectedSection: Pick<ReviewSectionItem, "files" | "truncated" | "source"> | null,
 ): ReviewParsedDiff {
   if (previewDiff.kind === "empty") return previewDiff;
+  const untrackedOmitted = selectedSection?.source?.untrackedOmitted === true;
   const notice = selectedSection?.truncated
-    ? `This preview exceeds the size limit. Changes shown are incomplete.${selectedSection.files ? " Counts include all changes." : ""}`
-    : previewDiff.notice;
+    ? `This preview exceeds the size limit. Changes shown are incomplete.${selectedSection.files && !untrackedOmitted ? " Counts include all changes." : ""}`
+    : untrackedOmitted
+      ? UNTRACKED_OMITTED_NOTICE
+      : previewDiff.notice;
   if (previewDiff.kind !== "files" || !selectedSection?.files) return { ...previewDiff, notice };
   const totals = selectedSection.files.reduce(
     (total, file) => ({

apps/mobile/src/features/review/useReviewDiffData.ts

@@ -6,6 +6,7 @@ import { getCachedNativeReviewDiffData } from "./nativeReviewDiffAdapter";
 import { getCachedReviewParsedDiff } from "./reviewState";
 import {
   applyReviewDiffMetadata,
+  UNTRACKED_OMITTED_NOTICE,
   buildReviewParsedDiff,
   type ReviewParsedDiff,
   type ReviewRenderableFile,
@@ -225,7 +226,7 @@ export function useReviewDiffData(input: {
       fileCount: files.length,
       additions: files.reduce((total, file) => total + file.additions, 0),
       deletions: files.reduce((total, file) => total + file.deletions, 0),
-      notice: null,
+      notice: lazySource.untrackedOmitted ? UNTRACKED_OMITTED_NOTICE : null,
     };
   }, [lazySource, previewDiff, selectedSection, patches]);
   const headerDiffSummary = useMemo(

apps/server/src/vcs/GitVcsDriverCore.test.ts

@@ -2645,6 +2645,42 @@ it.layer(layerTest)("GitVcsDriver core integration", (it) => {
       }),
     );
 
+    it.effect("leaves oversized untracked files out of review input", () =>
+      Effect.gen(function* () {
+        const cwd = yield* makeTmpDir();
+        yield* initRepoWithCommit(cwd);
+        const fileSystem = yield* FileSystem.FileSystem;
+        const pathService = yield* Path.Path;
+        const driver = yield* GitVcsDriver.GitVcsDriver;
+        yield* writeTextFile(cwd, "README.md", "# test\ntracked edit\n");
+        yield* writeTextFile(cwd, "ordinary.txt", "ordinary edit\n");
+        yield* writeTextFile(cwd, "large.data", "");
+        // Sparse fixture exercises logical size without allocating the input budget.
+        yield* fileSystem.truncate(pathService.join(cwd, "large.data"), 257 * 1024 * 1024);
+        if (symlinksSupported) {
+          yield* fileSystem.symlink("large.data", pathService.join(cwd, "ordinary-link"));
+        }
+
+        const preview = yield* driver.getReviewDiffPreview({ cwd, metadataOnly: true });
+        const source = preview.sources.find((item) => item.kind === "working-tree")!;
+        assert.isTrue(source.untrackedOmitted);
+        assert.deepStrictEqual(
+          source.files?.map((file) => file.path),
+          symlinksSupported
+            ? ["README.md", "ordinary-link", "ordinary.txt"]
+            : ["README.md", "ordinary.txt"],
+        );
+        const status = yield* driver.statusDetailsLocal(cwd, { includeBranchChanges: true });
+        assert.isUndefined(status.branchChanges);
+        const oversized = yield* driver.getReviewDiffPreview({
+          cwd,
+          file: { path: "large.data", previousPath: null, sourceKind: "working-tree" },
+        });
+        assert.isTrue(oversized.sources[0]!.untrackedOmitted);
+        assert.isEmpty(oversized.sources[0]!.diff);
+      }),
+    );
+
     it.effect("reviews untracked files outside the sparse-checkout cone", () =>
       Effect.gen(function* () {
         const cwd = yield* makeTmpDir();

apps/server/src/vcs/GitVcsDriverCore.ts

@@ -76,6 +76,8 @@ const REVIEW_DIFF_PATCH_MAX_OUTPUT_BYTES = 120_000;
 const REVIEW_METADATA_MAX_OUTPUT_BYTES = 16 * 1024 * 1024;
 // Temporary-index git add scales poorly (50k files took ~30 s); report incomplete totals above this cap.
 const REVIEW_UNTRACKED_MAX_FILES = 5_000;
+// git diff --numstat reads ~5 ms/MB of untracked text; larger files are left out of the review index.
+const REVIEW_UNTRACKED_MAX_TOTAL_BYTES = 256n * 1024n * 1024n;
 const REVIEW_DIFF_FILE_MAX_OUTPUT_BYTES = 1024 * 1024;
 const REVIEW_BRANCH_COMMIT_LIMIT = 100;
 const REVIEW_BRANCH_SUBJECT_LIMIT = 300;
@@ -3169,9 +3171,23 @@ export const makeGitVcsDriverCore = Effect.fn("makeGitVcsDriverCore")(function*
       (candidate) =>
         onlyPath === undefined || candidate === onlyPath || candidate === `${onlyPath}/`,
     );
-    if (paths.length === 0) return { env: undefined };
+    if (paths.length === 0) return { env: undefined, omitted: false };
     if (paths.length > REVIEW_UNTRACKED_MAX_FILES) return null;
-    const env = yield* prepareReviewIndex(cwd, paths).pipe(
+    const boundedPaths: string[] = [];
+    let bytes = 0n;
+    for (const relativePath of paths) {
+      // lstat reads logical size without following symlinks.
+      const info = yield* fileSystem
+        .lstat(path.resolve(cwd, relativePath))
+        .pipe(Effect.orElseSucceed(() => undefined));
+      const size = info?.type === "File" || info?.type === "SymbolicLink" ? info.size : 0n;
+      if (bytes + size > REVIEW_UNTRACKED_MAX_TOTAL_BYTES) continue;
+      bytes += size;
+      boundedPaths.push(relativePath);
+    }
+    const omitted = boundedPaths.length < paths.length;
+    if (boundedPaths.length === 0) return { env: undefined, omitted };
+    const env = yield* prepareReviewIndex(cwd, boundedPaths).pipe(
       Effect.catchTags({
         PlatformError: (cause) =>
           Effect.fail(
@@ -3185,7 +3201,7 @@ export const makeGitVcsDriverCore = Effect.fn("makeGitVcsDriverCore")(function*
           ),
       }),
     );
-    return { env };
+    return { env, omitted };
   });
 
   const resolveReviewMergeBase = Effect.fn("resolveReviewMergeBase")(function* (
@@ -3262,12 +3278,12 @@ export const makeGitVcsDriverCore = Effect.fn("makeGitVcsDriverCore")(function*
         : [];
     // Empty status can mean untracked files are hidden; retain the full scan.
     const untracked = yield* prepareUntrackedReviewIndex(cwd, pathspecs);
-    if (untracked === null) {
+    if (untracked === null || untracked.omitted) {
       return yield* new GitCommandError({
         operation: "GitVcsDriver.readBranchChangeTotals",
         command: "git ls-files",
         cwd,
-        detail: "Too many untracked files to count.",
+        detail: "Untracked files exceed the review input limits.",
       });
     }
     const readNumstat = (ref: string) =>
@@ -3594,9 +3610,9 @@ export const makeGitVcsDriverCore = Effect.fn("makeGitVcsDriverCore")(function*
       );
       return { ...patch, files: stat.files };
     });
-    const [dirtyTrackedResult, baseResult] = yield* Effect.gen(function* () {
+    const [dirtyTrackedResult, baseResult, untrackedOmitted] = yield* Effect.gen(function* () {
       const untracked = input.trackedOnly
-        ? { env: undefined }
+        ? { env: undefined, omitted: false }
         : yield* prepareUntrackedReviewIndex(cwd, pathArgs, input.file?.path);
       const metadataOnly = input.metadataOnly === true && !input.file && untracked !== null;
       const [dirty, base] =
@@ -3611,10 +3627,10 @@ export const makeGitVcsDriverCore = Effect.fn("makeGitVcsDriverCore")(function*
               ],
               { concurrency: 2 },
             );
-      if (untracked !== null) return [dirty, base] as const;
+      if (untracked !== null) return [dirty, base, untracked.omitted] as const;
       const incomplete = (ref: string | null, result: typeof dirty) =>
         ref === null ? result : { ...result, files: undefined, stdoutTruncated: true };
-      return [incomplete(dirtyRef, dirty), incomplete(review.mergeBase, base)] as const;
+      return [incomplete(dirtyRef, dirty), incomplete(review.mergeBase, base), false] as const;
     }).pipe(Effect.scoped);
     const dirtyFiles = dirtyTrackedResult.files;
     const baseFiles = baseResult.files;
@@ -3636,6 +3652,7 @@ export const makeGitVcsDriverCore = Effect.fn("makeGitVcsDriverCore")(function*
         ...(dirtyFiles === undefined ? {} : { files: dirtyFiles }),
         diffHash: dirtyDiffHash,
         truncated: dirtyTrackedResult.stdoutTruncated,
+        ...(untrackedOmitted ? { untrackedOmitted } : {}),
         ...(input.metadataOnly && !input.file && dirtyFiles !== undefined
           ? { patchesDeferred: true }
           : {}),
@@ -3650,6 +3667,7 @@ export const makeGitVcsDriverCore = Effect.fn("makeGitVcsDriverCore")(function*
         ...(baseFiles === undefined ? {} : { files: baseFiles }),
         diffHash: baseDiffHash,
         truncated: baseResult.stdoutTruncated,
+        ...(untrackedOmitted ? { untrackedOmitted } : {}),
         ...(input.metadataOnly && !input.file && baseFiles !== undefined
           ? { patchesDeferred: true }
           : {}),

apps/web/src/components/DiffPanel.tsx

@@ -1308,10 +1308,18 @@ export default function DiffPanel({
                   : "Showing tracked changes. Checking untracked files..."}
               </p>
             )}
+            {isGitSelection && selectedGitSource?.untrackedOmitted && (
+              <p className="shrink-0 border-b border-border/70 bg-muted/40 px-3 py-1.5 text-2xs text-muted-foreground">
+                Some untracked files are too large to review. They are not shown or counted.
+              </p>
+            )}
             {isSelectedPatchTruncated && !lazySource && (
               <p className="shrink-0 border-b border-border/70 bg-muted/40 px-3 py-1.5 text-2xs text-muted-foreground">
                 This preview exceeds the size limit. Changes shown are incomplete.
-                {isGitSelection && selectedGitSource?.files && !preview?.incomplete
+                {isGitSelection &&
+                selectedGitSource?.files &&
+                !preview?.incomplete &&
+                !selectedGitSource.untrackedOmitted
                   ? " Totals include all changes."
                   : ""}
               </p>

packages/contracts/src/review.ts

@@ -65,6 +65,8 @@ export const ReviewDiffPreviewSource = Schema.Struct({
   diffHash: TrimmedNonEmptyString,
   truncated: Schema.Boolean,
   patchesDeferred: Schema.optionalKey(Schema.Boolean),
+  // Untracked files past the review size budget are left out of the diff, files and totals.
+  untrackedOmitted: Schema.optionalKey(Schema.Boolean),
   files: Schema.optionalKey(Schema.Array(ReviewDiffFileStat)),
 });
 export type ReviewDiffPreviewSource = typeof ReviewDiffPreviewSource.Type;