fix: Fix review showing empty files + propagate diff errors to UI

apps/hook/server/index.ts

@@ -68,7 +68,7 @@ if (args[0] === "review") {
   const gitContext = await getGitContext();
 
   // Run git diff HEAD (uncommitted changes - default)
-  const { patch: rawPatch, label: gitRef } = await runGitDiff(
+  const { patch: rawPatch, label: gitRef, error: diffError } = await runGitDiff(
     "uncommitted",
     gitContext.defaultBranch
   );
@@ -77,6 +77,7 @@ if (args[0] === "review") {
   const server = await startReviewServer({
     rawPatch,
     gitRef,
+    error: diffError,
     origin: "claude-code",
     diffType: "uncommitted",
     gitContext,

apps/opencode-plugin/index.ts

@@ -160,7 +160,7 @@ Do NOT proceed with implementation until your plan is approved.
         const gitContext = await getGitContext();
 
         // Run git diff HEAD (uncommitted changes - default)
-        const { patch: rawPatch, label: gitRef } = await runGitDiff(
+        const { patch: rawPatch, label: gitRef, error: diffError } = await runGitDiff(
           "uncommitted",
           gitContext.defaultBranch
         );
@@ -169,6 +169,7 @@ Do NOT proceed with implementation until your plan is approved.
         const server = await startReviewServer({
           rawPatch,
           gitRef,
+          error: diffError,
           origin: "opencode",
           diffType: "uncommitted",
           gitContext,

apps/pi-extension/server.ts

@@ -389,15 +389,15 @@ export function getGitContext(): GitContext {
 export function runGitDiff(diffType: DiffType, defaultBranch = "main"): { patch: string; label: string } {
   switch (diffType) {
     case "uncommitted":
-      return { patch: git("diff HEAD"), label: "Uncommitted changes" };
+      return { patch: git("diff HEAD --src-prefix=a/ --dst-prefix=b/"), label: "Uncommitted changes" };
     case "staged":
-      return { patch: git("diff --staged"), label: "Staged changes" };
+      return { patch: git("diff --staged --src-prefix=a/ --dst-prefix=b/"), label: "Staged changes" };
     case "unstaged":
-      return { patch: git("diff"), label: "Unstaged changes" };
+      return { patch: git("diff --src-prefix=a/ --dst-prefix=b/"), label: "Unstaged changes" };
     case "last-commit":
-      return { patch: git("diff HEAD~1..HEAD"), label: "Last commit" };
+      return { patch: git("diff HEAD~1..HEAD --src-prefix=a/ --dst-prefix=b/"), label: "Last commit" };
     case "branch":
-      return { patch: git(`diff ${defaultBranch}..HEAD`), label: `Changes vs ${defaultBranch}` };
+      return { patch: git(`diff ${defaultBranch}..HEAD --src-prefix=a/ --dst-prefix=b/`), label: `Changes vs ${defaultBranch}` };
     default:
       return { patch: "", label: "Unknown diff type" };
   }

packages/review-editor/App.tsx

@@ -149,6 +149,7 @@ const ReviewApp: React.FC = () => {
   const [diffType, setDiffType] = useState<string>('uncommitted');
   const [gitContext, setGitContext] = useState<GitContext | null>(null);
   const [isLoadingDiff, setIsLoadingDiff] = useState(false);
+  const [diffError, setDiffError] = useState<string | null>(null);
   const [isSendingFeedback, setIsSendingFeedback] = useState(false);
   const [isApproving, setIsApproving] = useState(false);
   const [submitted, setSubmitted] = useState<'approved' | 'feedback' | false>(false);
@@ -209,6 +210,7 @@ const ReviewApp: React.FC = () => {
         gitContext?: GitContext;
         sharingEnabled?: boolean;
         repoInfo?: { display: string; branch?: string };
+        error?: string;
       }) => {
         const apiFiles = parseDiffToFiles(data.rawPatch);
         setDiffData({
@@ -226,6 +228,7 @@ const ReviewApp: React.FC = () => {
         if (data.gitContext) setGitContext(data.gitContext);
         if (data.sharingEnabled !== undefined) setSharingEnabled(data.sharingEnabled);
         if (data.repoInfo) setRepoInfo(data.repoInfo);
+        if (data.error) setDiffError(data.error);
       })
       .catch(() => {
         // Not in API mode - use demo content
@@ -340,10 +343,12 @@ const ReviewApp: React.FC = () => {
       setDiffType(data.diffType);
       setActiveFileIndex(0);
       setPendingSelection(null);
+      setDiffError((data as { error?: string }).error || null);
       // Note: We keep existing annotations - they may still be relevant
       // or user can clear them manually
     } catch (err) {
       console.error('Failed to switch diff:', err);
+      setDiffError(err instanceof Error ? err.message : 'Failed to switch diff');
     } finally {
       setIsLoadingDiff(false);
     }
@@ -763,20 +768,35 @@ const ReviewApp: React.FC = () => {
             ) : (
               <div className="h-full flex items-center justify-center">
                 <div className="text-center space-y-3 max-w-md px-8">
-                  <div className="mx-auto w-12 h-12 rounded-full bg-muted/50 flex items-center justify-center">
-                    <svg className="w-6 h-6 text-muted-foreground" fill="none" viewBox="0 0 24 24" stroke="currentColor" strokeWidth={1.5}>
-                      <path strokeLinecap="round" strokeLinejoin="round" d="M19.5 14.25v-2.625a3.375 3.375 0 00-3.375-3.375h-1.5A1.125 1.125 0 0113.5 7.125v-1.5a3.375 3.375 0 00-3.375-3.375H8.25m0 12.75h7.5m-7.5 3H12M10.5 2.25H5.625c-.621 0-1.125.504-1.125 1.125v17.25c0 .621.504 1.125 1.125 1.125h12.75c.621 0 1.125-.504 1.125-1.125V11.25a9 9 0 00-9-9z" />
-                    </svg>
+                  <div className={`mx-auto w-12 h-12 rounded-full flex items-center justify-center ${diffError ? 'bg-destructive/10' : 'bg-muted/50'}`}>
+                    {diffError ? (
+                      <svg className="w-6 h-6 text-destructive" fill="none" viewBox="0 0 24 24" stroke="currentColor" strokeWidth={1.5}>
+                        <path strokeLinecap="round" strokeLinejoin="round" d="M12 9v3.75m-9.303 3.376c-.866 1.5.217 3.374 1.948 3.374h14.71c1.73 0 2.813-1.874 1.948-3.374L13.949 3.378c-.866-1.5-3.032-1.5-3.898 0L2.697 16.126zM12 15.75h.007v.008H12v-.008z" />
+                      </svg>
+                    ) : (
+                      <svg className="w-6 h-6 text-muted-foreground" fill="none" viewBox="0 0 24 24" stroke="currentColor" strokeWidth={1.5}>
+                        <path strokeLinecap="round" strokeLinejoin="round" d="M19.5 14.25v-2.625a3.375 3.375 0 00-3.375-3.375h-1.5A1.125 1.125 0 0113.5 7.125v-1.5a3.375 3.375 0 00-3.375-3.375H8.25m0 12.75h7.5m-7.5 3H12M10.5 2.25H5.625c-.621 0-1.125.504-1.125 1.125v17.25c0 .621.504 1.125 1.125 1.125h12.75c.621 0 1.125-.504 1.125-1.125V11.25a9 9 0 00-9-9z" />
+                      </svg>
+                    )}
                   </div>
                   <div>
-                    <h3 className="text-sm font-medium text-foreground">No changes</h3>
-                    <p className="text-xs text-muted-foreground mt-1">
-                      {diffType === 'uncommitted' && "No uncommitted changes to review."}
-                      {diffType === 'staged' && "No staged changes. Stage some files with git add."}
-                      {diffType === 'unstaged' && "No unstaged changes. All changes are staged."}
-                      {diffType === 'last-commit' && "No changes in the last commit."}
-                      {diffType === 'branch' && `No changes between this branch and ${gitContext?.defaultBranch || 'main'}.`}
-                    </p>
+                    {diffError ? (
+                      <>
+                        <h3 className="text-sm font-medium text-destructive">Failed to load diff</h3>
+                        <p className="text-xs text-muted-foreground mt-1">{diffError}</p>
+                      </>
+                    ) : (
+                      <>
+                        <h3 className="text-sm font-medium text-foreground">No changes</h3>
+                        <p className="text-xs text-muted-foreground mt-1">
+                          {diffType === 'uncommitted' && "No uncommitted changes to review."}
+                          {diffType === 'staged' && "No staged changes. Stage some files with git add."}
+                          {diffType === 'unstaged' && "No unstaged changes. All changes are staged."}
+                          {diffType === 'last-commit' && "No changes in the last commit."}
+                          {diffType === 'branch' && `No changes between this branch and ${gitContext?.defaultBranch || 'main'}.`}
+                        </p>
+                      </>
+                    )}
                   </div>
                   {gitContext?.diffOptions && gitContext.diffOptions.length > 1 && (
                     <p className="text-xs text-muted-foreground/60">

packages/server/git.ts

@@ -28,6 +28,7 @@ export interface GitContext {
 export interface DiffResult {
   patch: string;
   label: string;
+  error?: string;
 }
 
 /**
@@ -108,27 +109,27 @@ export async function runGitDiff(
   try {
     switch (diffType) {
       case "uncommitted":
-        patch = (await $`git diff HEAD`.quiet()).text();
+        patch = (await $`git diff HEAD --src-prefix=a/ --dst-prefix=b/`.quiet()).text();
         label = "Uncommitted changes";
         break;
 
       case "staged":
-        patch = (await $`git diff --staged`.quiet()).text();
+        patch = (await $`git diff --staged --src-prefix=a/ --dst-prefix=b/`.quiet()).text();
         label = "Staged changes";
         break;
 
       case "unstaged":
-        patch = (await $`git diff`.quiet()).text();
+        patch = (await $`git diff --src-prefix=a/ --dst-prefix=b/`.quiet()).text();
         label = "Unstaged changes";
         break;
 
       case "last-commit":
-        patch = (await $`git diff HEAD~1..HEAD`.quiet()).text();
+        patch = (await $`git diff HEAD~1..HEAD --src-prefix=a/ --dst-prefix=b/`.quiet()).text();
         label = "Last commit";
         break;
 
       case "branch":
-        patch = (await $`git diff ${defaultBranch}..HEAD`.quiet()).text();
+        patch = (await $`git diff ${defaultBranch}..HEAD --src-prefix=a/ --dst-prefix=b/`.quiet()).text();
         label = `Changes vs ${defaultBranch}`;
         break;
 
@@ -139,8 +140,10 @@ export async function runGitDiff(
   } catch (error) {
     // Handle errors gracefully (e.g., no commits yet, invalid ref)
     console.error(`Git diff error for ${diffType}:`, error);
+    const errorMessage = error instanceof Error ? error.message : String(error);
     patch = "";
     label = `Error: ${diffType}`;
+    return { patch, label, error: errorMessage };
   }
 
   return { patch, label };

packages/server/review.ts

@@ -28,6 +28,8 @@ export interface ReviewServerOptions {
   rawPatch: string;
   /** Git ref used for the diff (e.g., "HEAD", "main..HEAD", "--staged") */
   gitRef: string;
+  /** Error message if git diff failed */
+  error?: string;
   /** HTML content to serve for the UI */
   htmlContent: string;
   /** Origin identifier for UI customization */
@@ -89,6 +91,7 @@ export async function startReviewServer(
   let currentPatch = options.rawPatch;
   let currentGitRef = options.gitRef;
   let currentDiffType: DiffType = options.diffType || "uncommitted";
+  let currentError = options.error;
 
   const isRemote = isRemoteSession();
   const configuredPort = getServerPort();
@@ -132,6 +135,7 @@ export async function startReviewServer(
               sharingEnabled,
               shareBaseUrl,
               repoInfo,
+              ...(currentError && { error: currentError }),
             });
           }
 
@@ -156,11 +160,13 @@ export async function startReviewServer(
               currentPatch = result.patch;
               currentGitRef = result.label;
               currentDiffType = newDiffType;
+              currentError = result.error;
 
               return Response.json({
                 rawPatch: currentPatch,
                 gitRef: currentGitRef,
                 diffType: currentDiffType,
+                ...(currentError && { error: currentError }),
               });
             } catch (err) {
               const message =