Commit Messages: Fix bug with unstaged files (#3150)

## Description

This PR:
- Fixes an issue where VS Code would provide `changes` as an empty array
for unstaged files
- Adds a e2e test to cover this
- Adds an item to the Cody feature menu to enable/disable the setting

## Test plan

1. Trigger the Cody commit message with no staged files
2. Check it works!

Other:

1. Check that disabling/enabling the feature from the menu works

<!-- Required. See
https://sourcegraph.com/docs/dev/background-information/testing_principles.
-->

Author: umpox

vscode/package.json

@@ -852,7 +852,7 @@
                     "order": 99,
                     "type": "boolean",
                     "default": true,
-                    "markdownDescription": "Adds a button to the SCM input field to generate a relevant commit message for the current changes."
+                    "markdownDescription": "Enable Cody to appear in the Source Control input field, to generate a relevant commit message from your changes."
                 },
                 "cody.debug.enable": {
                     "order": 99,

vscode/src/scm/CommitMessageProvider.ts

@@ -63,7 +63,12 @@ export class CommitMessageProvider implements VSCodeCommitMessageProvider, vscod
             hasV2Event: true,
         })
         telemetryRecorder.recordEvent('cody.command.generateCommitMessage', 'clicked')
-        const humanPrompt = await this.getHumanPrompt(changes)
+
+        // Filter out any empty changes.
+        // The Git extension seems to provide empty strings for unstaged changes.
+        const diffs = changes.filter(diff => diff.trim().length > 0)
+
+        const humanPrompt = await this.getHumanPrompt(diffs)
         if (!humanPrompt) {
             return Promise.reject()
         }

vscode/src/services/StatusBar.ts

@@ -158,6 +158,13 @@ export function createStatusBar(): CodyStatusBar {
                 c => c.experimentalSymfContext,
                 false
             ),
+            await createFeatureToggle(
+                'Commit Messages',
+                'Experimental',
+                'Enable Cody to appear in the Source Control input field, to generate a relevant commit message from your changes.',
+                'cody.experimental.commitMessage',
+                c => c.experimentalCommitMessage
+            ),
             { label: 'settings', kind: vscode.QuickPickItemKind.Separator },
             {
                 label: '$(gear) Cody Extension Settings',

vscode/test/e2e/commit-message.test.ts

@@ -24,12 +24,28 @@ const test = baseTest
             await withTempDir(async dir => {
                 // Initialize a git repository there
                 await spawn('git', ['init'], { cwd: dir })
+                await spawn('git', ['config', 'user.name', 'Test User'], {
+                    cwd: dir,
+                })
+                await spawn('git', ['config', 'user.email', 'test@example.host'], { cwd: dir })
 
                 // Add Cody ignore
                 await fs.mkdir(path.join(dir, '.cody'), { recursive: true })
                 await fs.writeFile(path.join(dir, '.cody', 'ignore'), 'ignored.js')
 
-                // Add some content
+                // Add empty files to change later
+                await Promise.all([
+                    fs.writeFile(path.join(dir, 'index.js'), ''),
+                    fs.writeFile(path.join(dir, 'ignored.js'), ''),
+                ])
+
+                // Commit initial files
+                await spawn('git', ['add', '.'], { cwd: dir })
+                await spawn('git', ['commit', '-m', 'Initial commit'], {
+                    cwd: dir,
+                })
+
+                // Add some content to try to commit in our tests
                 await Promise.all([
                     fs.writeFile(path.join(dir, 'index.js'), '// Hello World'),
                     fs.writeFile(path.join(dir, 'ignored.js'), '// Ignore me!'),
@@ -44,7 +60,7 @@ test.beforeEach(() => {
     mockServer.resetLoggedEvents()
 })
 
-test('commit message generation - happy path', async ({ page, sidebar }) => {
+test('commit message generation - happy path with staged changes', async ({ page, sidebar }) => {
     // Sign into Cody
     await sidebarSignin(page, sidebar)
 
@@ -55,7 +71,7 @@ test('commit message generation - happy path', async ({ page, sidebar }) => {
         .click()
 
     // Check the change is showing as a Git change
-    const gitChange = page.getByLabel('index.js, Untracked')
+    const gitChange = page.getByLabel('index.js • Modified')
     await expect(gitChange).toBeVisible()
 
     // Stage Git change
@@ -80,6 +96,38 @@ test('commit message generation - happy path', async ({ page, sidebar }) => {
     ).toBeVisible()
 })
 
+test('commit message generation - happy path with no staged changes', async ({ page, sidebar }) => {
+    // Sign into Cody
+    await sidebarSignin(page, sidebar)
+
+    // Open the Source Control view
+    await page
+        .getByLabel(/Source Control/)
+        .nth(2)
+        .click()
+
+    // Check the change is showing as a Git change
+    const gitChange = page.getByLabel('index.js • Modified')
+    await expect(gitChange).toBeVisible()
+
+    // Activate the Cody commit message feature
+    const generateCommitMessageCta = await page.getByLabel('Generate Commit Message (Cody)')
+    expect(generateCommitMessageCta).toBeVisible()
+    await generateCommitMessageCta.hover()
+    await generateCommitMessageCta.click()
+
+    const expectedEvents = [
+        'CodyVSCodeExtension:command:generateCommitMessage:clicked',
+        'CodyVSCodeExtension:command:generateCommitMessage:executed',
+    ]
+    await assertEvents(mockServer.loggedEvents, expectedEvents)
+
+    // Check generated content is displayed in the source control input
+    await expect(
+        page.getByLabel('Source Control Input').getByText('hello from the assistant')
+    ).toBeVisible()
+})
+
 test('commit message generation - cody ignore', async ({ page, sidebar }) => {
     // Sign into Cody
     await sidebarSignin(page, sidebar)
@@ -91,7 +139,7 @@ test('commit message generation - cody ignore', async ({ page, sidebar }) => {
         .click()
 
     // Check the change is showing as a Git change
-    const gitChange = page.getByLabel('ignored.js, Untracked')
+    const gitChange = page.getByLabel('ignored.js • Modified')
     await expect(gitChange).toBeVisible()
 
     // Stage Git change