fix(cli): return proper errors from loadExtensionConfig (#8909)

Co-authored-by: Taneja Hriday <hridayt@google.com>

packages/cli/src/config/extension.test.ts

@@ -373,6 +373,70 @@ describe('extension tests', () => {
       expect(serverConfig.env!.MISSING_VAR_BRACES).toBe('${ALSO_UNDEFINED}');
     });
 
+    it('should skip extensions with invalid JSON and log a warning', () => {
+      const consoleSpy = vi
+        .spyOn(console, 'error')
+        .mockImplementation(() => {});
+
+      // Good extension
+      createExtension({
+        extensionsDir: userExtensionsDir,
+        name: 'good-ext',
+        version: '1.0.0',
+      });
+
+      // Bad extension
+      const badExtDir = path.join(userExtensionsDir, 'bad-ext');
+      fs.mkdirSync(badExtDir);
+      const badConfigPath = path.join(badExtDir, EXTENSIONS_CONFIG_FILENAME);
+      fs.writeFileSync(badConfigPath, '{ "name": "bad-ext"'); // Malformed
+
+      const extensions = loadExtensions();
+
+      expect(extensions).toHaveLength(1);
+      expect(extensions[0].config.name).toBe('good-ext');
+      expect(consoleSpy).toHaveBeenCalledOnce();
+      expect(consoleSpy).toHaveBeenCalledWith(
+        expect.stringContaining(
+          `Warning: Skipping extension in ${badExtDir}: Failed to load extension config from ${badConfigPath}`,
+        ),
+      );
+
+      consoleSpy.mockRestore();
+    });
+
+    it('should skip extensions with missing name and log a warning', () => {
+      const consoleSpy = vi
+        .spyOn(console, 'error')
+        .mockImplementation(() => {});
+
+      // Good extension
+      createExtension({
+        extensionsDir: userExtensionsDir,
+        name: 'good-ext',
+        version: '1.0.0',
+      });
+
+      // Bad extension
+      const badExtDir = path.join(userExtensionsDir, 'bad-ext-no-name');
+      fs.mkdirSync(badExtDir);
+      const badConfigPath = path.join(badExtDir, EXTENSIONS_CONFIG_FILENAME);
+      fs.writeFileSync(badConfigPath, JSON.stringify({ version: '1.0.0' }));
+
+      const extensions = loadExtensions();
+
+      expect(extensions).toHaveLength(1);
+      expect(extensions[0].config.name).toBe('good-ext');
+      expect(consoleSpy).toHaveBeenCalledOnce();
+      expect(consoleSpy).toHaveBeenCalledWith(
+        expect.stringContaining(
+          `Warning: Skipping extension in ${badExtDir}: Failed to load extension config from ${badConfigPath}: Invalid configuration in ${badConfigPath}: missing "name"`,
+        ),
+      );
+
+      consoleSpy.mockRestore();
+    });
+
     it('should filter trust out of mcp servers', () => {
       createExtension({
         extensionsDir: userExtensionsDir,
@@ -591,15 +655,49 @@ describe('extension tests', () => {
     it('should throw an error and cleanup if gemini-extension.json is missing', async () => {
       const sourceExtDir = path.join(tempHomeDir, 'bad-extension');
       fs.mkdirSync(sourceExtDir, { recursive: true });
+      const configPath = path.join(sourceExtDir, EXTENSIONS_CONFIG_FILENAME);
+
+      await expect(
+        installExtension({ source: sourceExtDir, type: 'local' }),
+      ).rejects.toThrow(`Configuration file not found at ${configPath}`);
+
+      const targetExtDir = path.join(userExtensionsDir, 'bad-extension');
+      expect(fs.existsSync(targetExtDir)).toBe(false);
+    });
+
+    it('should throw an error for invalid JSON in gemini-extension.json', async () => {
+      const sourceExtDir = path.join(tempHomeDir, 'bad-json-ext');
+      fs.mkdirSync(sourceExtDir, { recursive: true });
+      const configPath = path.join(sourceExtDir, EXTENSIONS_CONFIG_FILENAME);
+      fs.writeFileSync(configPath, '{ "name": "bad-json", "version": "1.0.0"'); // Malformed JSON
 
       await expect(
         installExtension({ source: sourceExtDir, type: 'local' }),
       ).rejects.toThrow(
-        `Invalid extension at ${sourceExtDir}. Please make sure it has a valid gemini-extension.json file.`,
+        new RegExp(
+          `^Failed to load extension config from ${configPath.replace(
+            /\\/g,
+            '\\\\',
+          )}`,
+        ),
       );
+    });
 
-      const targetExtDir = path.join(userExtensionsDir, 'bad-extension');
-      expect(fs.existsSync(targetExtDir)).toBe(false);
+    it('should throw an error for missing name in gemini-extension.json', async () => {
+      const sourceExtDir = createExtension({
+        extensionsDir: tempHomeDir,
+        name: 'missing-name-ext',
+        version: '1.0.0',
+      });
+      const configPath = path.join(sourceExtDir, EXTENSIONS_CONFIG_FILENAME);
+      // Overwrite with invalid config
+      fs.writeFileSync(configPath, JSON.stringify({ version: '1.0.0' }));
+
+      await expect(
+        installExtension({ source: sourceExtDir, type: 'local' }),
+      ).rejects.toThrow(
+        `Invalid configuration in ${configPath}: missing "name"`,
+      );
     });
 
     it('should install an extension from a git URL', async () => {