Implement session state tracking for "Run and Debug" button when Inte…

[Prashant Kumar Rai (8prashant)]

Fixes #13001

When C_Cpp.intelliSenseEngine is set to "disabled", the language server client is not started. Previously, cpptools.buildAndDebug.isSourceFile and cpptools.buildAndDebug.isFolderOpen context keys (which control the visibility of the "Run / Debug C/C++ File" and "Add Debug Configuration" editor action buttons) were only updated within the language server client (client.ts). Consequently, disabling IntelliSense would cause the Run/Debug shortcut buttons to never appear in the editor title bar.

This PR updates the Debugger extension initialization (Debugger/extension.ts) to track active text editor changes and keep buildAndDebugIsSourceFile and buildAndDebugIsFolderOpen up to date regardless of whether IntelliSense is enabled or disabled.

Changes

1. Added updateBuildAndDebugSessionState and registered an onDidChangeActiveTextEditor listener in DebuggerExtension.initialize.
2. Added unit tests in Extension/test/scenarios/SingleRootProject/tests/buildAndDebug.test.ts verifying session state updates for source files, header files, non-C/C++ files, and undefined editors.

Verification

• Compiled with TypeScript (yarn compile) with 0 errors.
• Ran tests via yarn test --scenario=SingleRootProject and verified all BuildAndDebug SessionState Tests pass.

[Copilot]

Pull request overview

Ensures Run/Debug editor actions remain available when IntelliSense is disabled.

Changes:

• Tracks active editor changes in the debugger extension.
• Updates build/debug session context keys.
• Adds source, header, non-C/C++, and undefined-editor tests.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
Extension/src/Debugger/extension.ts	Adds independent session-state tracking.
Extension/test/scenarios/SingleRootProject/tests/buildAndDebug.test.ts	Tests source-file state updates.

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[Sean McManus (sean-mcmanus)]

Found one session-state lifecycle gap that should be addressed before merging.

[Copilot]

Pull request overview

Copilot reviewed 2 out of 2 changed files in this pull request and generated 2 comments.

[Copilot]

Pull request overview

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

[Copilot]

🟡 Changes recommended

Active-document language-mode changes can leave the Run/Debug context stale.

Once you've addressed the issues Copilot identified, you can request another Copilot review.

Review details

• Files reviewed: 2/2 changed files
• Comments generated: 1
• Review effort level: Balanced

[Copilot]

🟢 Approval recommended

The implementation matches existing classification behavior and covers the reported regression with focused tests.

Review details

• Files reviewed: 2/2 changed files
• Comments generated: 0 new
• Review effort level: Balanced

[Prashant Kumar Rai (8prashant)]

Hi Sean McManus (@sean-mcmanus),
I have addressed all the review feedback
Could you please re-review the updated changes?
Thanks.

[Sean McManus (sean-mcmanus)]

The correctness fixes now look sound. One focused test-coverage gap remains for the new event-driven paths.

[Sean McManus (sean-mcmanus)]

✨Copilot (agent146): [Minor] Please add focused regression coverage for the event-driven behavior rather than testing only the exported helper. These four tests call updateBuildAndDebugSessionState directly, so they would still pass if any of the new onDidChangeActiveTextEditor, onDidOpenTextDocument, or onDidChangeWorkspaceFolders registrations were absent. They also never use a C++ URI outside the open workspace, so they would have passed the prior global-folder implementation as well. At minimum, add an external C++ source case that asserts isSourceFile === true and isFolderOpen === false, plus one listener-driven transition (ideally an active-document language change while IntelliSense is disabled) to cover the behavior this PR fixes.