fix: detect interrupted commands in terminal exit code hack

[Yogeshwaran C (yogeshwaran-c)]

What kind of change does this PR introduce?

Bug fix

What is the current behavior?

When a command is typed and interrupted with Ctrl+C (for example, echo test^C), the TerminalShellExecution end event can report an exit code inherited from the previous execution of the same command.

For example:

$ echo test     -> exit code 0 (correct)
$ echo test^C   -> exit code 0 (incorrect; should be undefined)

This happens because handleCommandFinished contains a workaround for versions of bash whose history output merges identical commands. When bash reports an undefined exit code and the shell integration reports the same command text as the previous command, the workaround reuses the previous exit code. An interrupted duplicate command therefore looks like the history-merge case and incorrectly inherits the previous result.

Closes #237517

What is the new behavior?

CommandDetectionCapability now listens to the existing PromptInputModel.onDidInterrupt event, which detects the Ctrl+C/ETX input directly. When the current command was interrupted, the duplicate-history workaround is skipped and the undefined exit code reported by the shell is preserved. This matches the documented TerminalShellExecutionEndEvent.exitCode contract for commands canceled via Ctrl+C.

The interrupted state is reset when the next prompt starts. Non-interrupted duplicate commands continue to use the existing bash history workaround unchanged.

Using the prompt input model's interrupt signal also avoids inferring cancellation from rendered ^C text, so a literal command ending in ^C is not treated as interrupted.

Additional context

The regression tests verify that:

1. An interrupted duplicate command keeps an undefined exit code instead of inheriting the previous command's exit code.
2. A non-interrupted duplicate command still inherits the previous exit code, including when its literal text ends in ^C.

The tests also retain the initial command in their expected command lists and no longer use unnecessary any casts.

Validation:

• commandDetectionCapability.test.ts: 10 passing
• npm run precommit: passed

[Megan Rogge (meganrogge)]

Thanks!

[Copilot]

Pull request overview

Fixes terminal shell execution exit codes for commands interrupted with Ctrl+C.

Changes:

• Detects raw command lines ending in ^C and reports exit code 130.
• Adds regression tests for interrupted and duplicate commands.

Show a summary per file

File	Description
commandDetectionCapability.ts	Adds interrupted-command detection.
commandDetectionCapability.test.ts	Adds regression tests; both assertions currently omit the initial command and fail.

Review details

Comments suppressed due to low confidence (2)

src/vs/workbench/contrib/terminal/test/browser/capabilities/commandDetectionCapability.test.ts:176

• The first printStandardCommand is still present when this assertion runs, so assertCommands compares two actual commands against one expected command and the test fails. Keep the prior command in the expected list since it is required for the inheritance scenario.

		assertCommands([
			{ command: 'echo test', exitCode: 0, cwd: undefined, marker: { line: 2 } }
		]);

src/vs/workbench/contrib/terminal/test/browser/capabilities/commandDetectionCapability.test.ts:170

• The method parameter is number | undefined, making this any cast unnecessary and contrary to the repository's no-any guideline.

		capability.handleCommandFinished(undefined as any);

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

[Dmitriy Vasyura (dmitrivMS)]

Updated the fix in cfa3acd:

• Use the existing PromptInputModel.onDidInterrupt signal instead of inferring Ctrl+C from rendered ^C text.
• Preserve an undefined exit code for canceled commands, matching the TerminalShellExecutionEndEvent.exitCode API contract, rather than synthesizing exit code 130.
• Keep the duplicate bash history workaround for non-interrupted commands.
• Update the regression tests to model the duplicate-history command line, include the initial command in expectations, remove the unnecessary any casts, and verify literal ^C text is not treated as an interruption.

Validation:

• commandDetectionCapability.test.ts: 10 passing
• npm run precommit: passed