fix(core): handle ENAMETOOLONG in robustRealpath

- Add ENAMETOOLONG to caught errors in robustRealpath to prevent crashes on long paths.
- Add regression test case to verify fix and prevent future regressions.

Fixes https://github.com/google-gemini/gemini-cli/issues/25696

packages/core/src/utils/paths.test.ts

@@ -601,6 +601,22 @@ describe('resolveToRealPath', () => {
       /Infinite recursion detected/,
     );
   });
+
+  it('should return path as-is if fs.realpathSync and fs.lstatSync fail with ENAMETOOLONG', () => {
+    vi.spyOn(fs, 'realpathSync').mockImplementation(() => {
+      const err = new Error('File name too long') as NodeJS.ErrnoException;
+      err.code = 'ENAMETOOLONG';
+      throw err;
+    });
+    vi.spyOn(fs, 'lstatSync').mockImplementation(() => {
+      const err = new Error('File name too long') as NodeJS.ErrnoException;
+      err.code = 'ENAMETOOLONG';
+      throw err;
+    });
+
+    const longPath = path.resolve('a'.repeat(5000));
+    expect(resolveToRealPath(longPath)).toBe(longPath);
+  });
 });
 
 describe('makeRelative', () => {

packages/core/src/utils/paths.ts

@@ -424,7 +424,7 @@ function robustRealpath(p: string, visited = new Set<string>()): string {
       e &&
       typeof e === 'object' &&
       'code' in e &&
-      (e.code === 'ENOENT' || e.code === 'EISDIR')
+      (e.code === 'ENOENT' || e.code === 'EISDIR' || e.code === 'ENAMETOOLONG')
     ) {
       try {
         const stat = fs.lstatSync(p);
@@ -435,13 +435,15 @@ function robustRealpath(p: string, visited = new Set<string>()): string {
         }
       } catch (lstatError: unknown) {
         // Not a symlink, or lstat failed. Re-throw if it's not an expected
-        // ENOENT (e.g., a permissions error), otherwise resolve parent.
+        // error (e.g., a permissions error), otherwise resolve parent.
         if (
           !(
             lstatError &&
             typeof lstatError === 'object' &&
             'code' in lstatError &&
-            (lstatError.code === 'ENOENT' || lstatError.code === 'EISDIR')
+            (lstatError.code === 'ENOENT' ||
+              lstatError.code === 'EISDIR' ||
+              lstatError.code === 'ENAMETOOLONG')
           )
         ) {
           throw lstatError;