Add extension name auto-complete to /extensions update (#10198)

Co-authored-by: gemini-code-assist[bot] <176961590+gemini-code-assist[bot]@users.noreply.github.com>

packages/cli/src/ui/commands/extensionsCommand.test.ts

@@ -251,5 +251,81 @@ describe('extensionsCommand', () => {
         expect.any(Number),
       );
     });
+
+    describe('completion', () => {
+      const updateCompletion = extensionsCommand.subCommands?.find(
+        (cmd) => cmd.name === 'update',
+      )?.completion;
+
+      if (!updateCompletion) {
+        throw new Error('Update completion not found');
+      }
+
+      const extensionOne: GeminiCLIExtension = {
+        name: 'ext-one',
+        version: '1.0.0',
+        isActive: true,
+        path: '/test/dir/ext-one',
+        installMetadata: {
+          type: 'git',
+          autoUpdate: false,
+          source: 'https://github.com/some/extension.git',
+        },
+      };
+      const extensionTwo: GeminiCLIExtension = {
+        name: 'another-ext',
+        version: '1.0.0',
+        isActive: true,
+        path: '/test/dir/another-ext',
+        installMetadata: {
+          type: 'git',
+          autoUpdate: false,
+          source: 'https://github.com/some/extension.git',
+        },
+      };
+      const allExt: GeminiCLIExtension = {
+        name: 'all-ext',
+        version: '1.0.0',
+        isActive: true,
+        path: '/test/dir/all-ext',
+        installMetadata: {
+          type: 'git',
+          autoUpdate: false,
+          source: 'https://github.com/some/extension.git',
+        },
+      };
+
+      it.each([
+        {
+          description: 'should return matching extension names',
+          extensions: [extensionOne, extensionTwo],
+          partialArg: 'ext',
+          expected: ['ext-one'],
+        },
+        {
+          description: 'should return --all when partialArg matches',
+          extensions: [],
+          partialArg: '--al',
+          expected: ['--all'],
+        },
+        {
+          description:
+            'should return both extension names and --all when both match',
+          extensions: [allExt],
+          partialArg: 'all',
+          expected: ['--all', 'all-ext'],
+        },
+        {
+          description: 'should return an empty array if no matches',
+          extensions: [extensionOne],
+          partialArg: 'nomatch',
+          expected: [],
+        },
+      ])('$description', async ({ extensions, partialArg, expected }) => {
+        mockGetExtensions.mockReturnValue(extensions);
+        const suggestions = await updateCompletion(mockContext, partialArg);
+        expect(suggestions).toEqual(expected);
+      });
+    });
   });
 });

packages/cli/src/ui/commands/extensionsCommand.ts

@@ -142,6 +142,19 @@ const updateExtensionsCommand: SlashCommand = {
   description: 'Update extensions. Usage: update <extension-names>|--all',
   kind: CommandKind.BUILT_IN,
   action: updateAction,
+  completion: async (context, partialArg) => {
+    const extensions = context.services.config?.getExtensions() ?? [];
+    const extensionNames = extensions.map((ext) => ext.name);
+    const suggestions = extensionNames.filter((name) =>
+      name.startsWith(partialArg),
+    );
+
+    if ('--all'.startsWith(partialArg) || 'all'.startsWith(partialArg)) {
+      suggestions.unshift('--all');
+    }
+
+    return suggestions;
+  },
 };
 
 export const extensionsCommand: SlashCommand = {