fix(core): silently skip GEMINI.md paths that are directories (EISDIR) (#25662)

Co-authored-by: Tommaso Sciortino <sciortino@gmail.com>

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

@@ -15,6 +15,7 @@ import {
   getEnvironmentMemoryPaths,
   loadJitSubdirectoryMemory,
   refreshServerHierarchicalMemory,
+  readGeminiMdFiles,
 } from './memoryDiscovery.js';
 import {
   setGeminiMdFilename,
@@ -682,6 +683,97 @@ included directory memory
     expect(childOccurrences).toBe(1);
   });
 
+  describe('EISDIR handling for GEMINI.md as a directory', () => {
+    it('readGeminiMdFiles returns null content (without throwing) when path is a directory', async () => {
+      const dirAsFilePath = await createEmptyDir(
+        path.join(cwd, DEFAULT_CONTEXT_FILENAME),
+      );
+
+      const results = await readGeminiMdFiles([dirAsFilePath]);
+
+      expect(results).toHaveLength(1);
+      expect(results[0].filePath).toBe(dirAsFilePath);
+      expect(results[0].content).toBeNull();
+    });
+
+    it('loadServerHierarchicalMemory ignores a GEMINI.md directory and returns empty memory', async () => {
+      // Create a directory named GEMINI.md where a regular file would be expected.
+      await createEmptyDir(path.join(cwd, DEFAULT_CONTEXT_FILENAME));
+
+      const result = flattenResult(
+        await loadServerHierarchicalMemory(
+          cwd,
+          [],
+          new FileDiscoveryService(projectRoot),
+          new SimpleExtensionLoader([]),
+          DEFAULT_FOLDER_TRUST,
+        ),
+      );
+
+      // EISDIR is silently skipped, so memory is empty (no readable file
+      // contents) and no exception propagates.
+      expect(result.memoryContent).toBe('');
+    });
+
+    it('falls back to a real GEMINI.md file at a higher level when a directory shadows the same name lower in the tree', async () => {
+      // Lower in the tree (cwd): a directory named GEMINI.md (invalid).
+      await createEmptyDir(path.join(cwd, DEFAULT_CONTEXT_FILENAME));
+      // Higher in the tree (projectRoot): a real GEMINI.md file (valid).
+      const projectContextFile = await createTestFile(
+        path.join(projectRoot, DEFAULT_CONTEXT_FILENAME),
+        'Project root memory content',
+      );
+
+      const result = flattenResult(
+        await loadServerHierarchicalMemory(
+          cwd,
+          [],
+          new FileDiscoveryService(projectRoot),
+          new SimpleExtensionLoader([]),
+          DEFAULT_FOLDER_TRUST,
+        ),
+      );
+
+      // The directory at cwd is silently skipped; the actual file at
+      // projectRoot is still discovered and loaded normally.
+      expect(result.memoryContent).toContain('Project root memory content');
+      expect(result.filePaths).toContain(projectContextFile);
+    });
+
+    it('silently skips a GEMINI.md symlink that points to a directory', async () => {
+      // Create a real directory elsewhere and symlink GEMINI.md to it.
+      const realDir = await createEmptyDir(path.join(cwd, '.geminimd-target'));
+      const symlinkPath = path.join(cwd, DEFAULT_CONTEXT_FILENAME);
+      try {
+        await fsPromises.symlink(realDir, symlinkPath, 'dir');
+      } catch (err) {
+        // Symlink creation may be unsupported on some Windows setups (no
+        // SeCreateSymbolicLinkPrivilege). Skip the test there rather than fail.
+        if (
+          err instanceof Error &&
+          (err as NodeJS.ErrnoException).code === 'EPERM'
+        ) {
+          return;
+        }
+        throw err;
+      }
+
+      const result = flattenResult(
+        await loadServerHierarchicalMemory(
+          cwd,
+          [],
+          new FileDiscoveryService(projectRoot),
+          new SimpleExtensionLoader([]),
+          DEFAULT_FOLDER_TRUST,
+        ),
+      );
+
+      // A symlink resolving to a directory triggers EISDIR on read in the
+      // same way a plain directory does and must be skipped silently.
+      expect(result.memoryContent).toBe('');
+    });
+  });
+
   describe('getGlobalMemoryPaths', () => {
     it('should find global memory file if it exists', async () => {
       const globalMemoryFile = await createTestFile(

packages/core/src/utils/memoryDiscovery.ts

@@ -406,19 +406,34 @@ export async function readGeminiMdFiles(
 
           return { filePath, content: processedResult.content };
         } catch (error: unknown) {
-          const isTestEnv =
-            process.env['NODE_ENV'] === 'test' || process.env['VITEST'];
-          if (!isTestEnv) {
-            const message =
-              error instanceof Error ? error.message : String(error);
-            logger.warn(
-              `Warning: Could not read ${getAllGeminiMdFilenames()} file at ${filePath}. Error: ${message}`,
+          const isEISDIR =
+            error instanceof Error &&
+            (error as NodeJS.ErrnoException).code === 'EISDIR';
+
+          if (isEISDIR) {
+            // A directory exists where a GEMINI.md file is expected.
+            // This is valid in some project structures (e.g. a folder named
+            // GEMINI.md held for organisational purposes) — skip it silently
+            // instead of surfacing a confusing warning to the user.
+            debugLogger.debug(
+              '[DEBUG] [MemoryDiscovery] Skipping directory at GEMINI.md path:',
+              filePath,
+            );
+          } else {
+            const isTestEnv =
+              process.env['NODE_ENV'] === 'test' || process.env['VITEST'];
+            if (!isTestEnv) {
+              const message =
+                error instanceof Error ? error.message : String(error);
+              logger.warn(
+                `Warning: Could not read ${getAllGeminiMdFilenames()} file at ${filePath}. Error: ${message}`,
+              );
+            }
+            debugLogger.debug(
+              '[DEBUG] [MemoryDiscovery] Failed to read:',
+              filePath,
             );
           }
-          debugLogger.debug(
-            '[DEBUG] [MemoryDiscovery] Failed to read:',
-            filePath,
-          );
           return { filePath, content: null }; // Still include it with null content
         }
       },