fix: expand untracked directories to show individual file diffs

Previously, when git status reported an untracked directory (e.g., "?? apps/"),
the code would try to read the directory as a file, which failed and showed
"[Unable to read file content]".

Now, when encountering a directory:
- Strip trailing slash from path (git reports dirs as "dirname/")
- Check if path is a directory using stats.isDirectory()
- Recursively list all files inside using listAllFilesInDirectory
- Generate synthetic diffs for each file found

This ensures users see the actual file contents in the diff view instead
of an error placeholder.

libs/git-utils/src/diff.ts

@@ -45,20 +45,24 @@ ${addedLines}
 /**
  * Generate a synthetic unified diff for an untracked (new) file
  * This is needed because `git diff HEAD` doesn't include untracked files
+ *
+ * If the path is a directory, this will recursively generate diffs for all files inside
  */
 export async function generateSyntheticDiffForNewFile(
   basePath: string,
   relativePath: string
 ): Promise<string> {
-  const fullPath = path.join(basePath, relativePath);
+  // Remove trailing slash if present (git status reports directories with trailing /)
+  const cleanPath = relativePath.endsWith('/') ? relativePath.slice(0, -1) : relativePath;
+  const fullPath = path.join(basePath, cleanPath);
 
   try {
     // Check if it's a binary file
-    if (isBinaryFile(relativePath)) {
-      return `diff --git a/${relativePath} b/${relativePath}
+    if (isBinaryFile(cleanPath)) {
+      return `diff --git a/${cleanPath} b/${cleanPath}
 new file mode 100644
 index 0000000..0000000
-Binary file ${relativePath} added
+Binary file ${cleanPath} added
 `;
     }
 
@@ -66,15 +70,23 @@ Binary file ${relativePath} added
     const stats = await secureFs.stat(fullPath);
 
     // Check if it's a directory (can happen with untracked directories from git status)
+    // If so, recursively list all files and generate diffs for each
     if (stats.isDirectory()) {
-      return createNewFileDiff(relativePath, '040000', ['[Directory]']);
+      const filesInDir = await listAllFilesInDirectory(basePath, cleanPath);
+      if (filesInDir.length === 0) {
+        // Empty directory
+        return createNewFileDiff(cleanPath, '040000', ['[Empty directory]']);
+      }
+      // Generate diffs for all files in the directory
+      const diffs = await Promise.all(
+        filesInDir.map((filePath) => generateSyntheticDiffForNewFile(basePath, filePath))
+      );
+      return diffs.join('');
     }
 
     if (stats.size > MAX_SYNTHETIC_DIFF_SIZE) {
       const sizeKB = Math.round(stats.size / 1024);
-      return createNewFileDiff(relativePath, '100644', [
-        `[File too large to display: ${sizeKB}KB]`,
-      ]);
+      return createNewFileDiff(cleanPath, '100644', [`[File too large to display: ${sizeKB}KB]`]);
     }
 
     // Read file content
@@ -91,11 +103,11 @@ Binary file ${relativePath} added
     const lineCount = lines.length;
     const addedLines = lines.map((line) => `+${line}`).join('\n');
 
-    let diff = `diff --git a/${relativePath} b/${relativePath}
+    let diff = `diff --git a/${cleanPath} b/${cleanPath}
 new file mode 100644
 index 0000000..0000000
 --- /dev/null
-+++ b/${relativePath}
++++ b/${cleanPath}
 @@ -0,0 +1,${lineCount} @@
 ${addedLines}`;
 
@@ -109,7 +121,7 @@ ${addedLines}`;
     // Log the error for debugging
     logger.error(`Failed to generate synthetic diff for ${fullPath}:`, error);
     // Return a placeholder diff
-    return createNewFileDiff(relativePath, '100644', ['[Unable to read file content]']);
+    return createNewFileDiff(cleanPath, '100644', ['[Unable to read file content]']);
   }
 }
 

libs/git-utils/tests/diff.test.ts

@@ -118,7 +118,7 @@ describe('diff.ts', () => {
       expect(diff).toContain('[Unable to read file content]');
     });
 
-    it('should handle directory path gracefully', async () => {
+    it('should handle empty directory path gracefully', async () => {
       const dirName = 'some-directory';
       const dirPath = path.join(tempDir, dirName);
       await fs.mkdir(dirPath);
@@ -127,7 +127,38 @@ describe('diff.ts', () => {
 
       expect(diff).toContain(`diff --git a/${dirName} b/${dirName}`);
       expect(diff).toContain('new file mode 040000');
-      expect(diff).toContain('[Directory]');
+      expect(diff).toContain('[Empty directory]');
+    });
+
+    it('should expand directory with files and generate diffs for each file', async () => {
+      const dirName = 'new-feature';
+      const dirPath = path.join(tempDir, dirName);
+      await fs.mkdir(dirPath);
+      await fs.writeFile(path.join(dirPath, 'index.ts'), 'export const foo = 1;\n');
+      await fs.writeFile(path.join(dirPath, 'utils.ts'), 'export const bar = 2;\n');
+
+      const diff = await generateSyntheticDiffForNewFile(tempDir, dirName);
+
+      // Should contain diffs for both files in the directory
+      expect(diff).toContain(`diff --git a/${dirName}/index.ts b/${dirName}/index.ts`);
+      expect(diff).toContain(`diff --git a/${dirName}/utils.ts b/${dirName}/utils.ts`);
+      expect(diff).toContain('+export const foo = 1;');
+      expect(diff).toContain('+export const bar = 2;');
+      // Should NOT contain a diff for the directory itself
+      expect(diff).not.toContain('[Empty directory]');
+    });
+
+    it('should handle directory path with trailing slash', async () => {
+      const dirName = 'trailing-slash-dir';
+      const dirPath = path.join(tempDir, dirName);
+      await fs.mkdir(dirPath);
+      await fs.writeFile(path.join(dirPath, 'file.txt'), 'content\n');
+
+      // git status reports untracked directories with trailing slash
+      const diff = await generateSyntheticDiffForNewFile(tempDir, `${dirName}/`);
+
+      expect(diff).toContain(`diff --git a/${dirName}/file.txt b/${dirName}/file.txt`);
+      expect(diff).toContain('+content');
     });
   });