Restore terminal cursor visibility on exit in collect-linux

[Copilot]

dotnet-trace collect-linux hides the cursor during trace collection but never restores it, leaving users with an invisible cursor after the tool exits.

Changes

• CollectLinuxCommand.cs: Add cursor restoration in finally block, matching the pattern in CollectCommand.cs

  • Only restores when !Console.IsOutputRedirected to avoid interfering with piped output
  • Guarantees restoration on all exit paths (normal, exception, cancellation)

• CollectLinuxCommandFunctionalTests.cs: Add tests verifying cursor state after command exits

  • Success path
  • Error path
  • Redirected output path

finally
{
    if (!Console.IsOutputRedirected)
    {
        Console.CursorVisible = true;
    }
    // ... existing cleanup code
}

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Original prompt

---

This section details on the original issue you should resolve

<issue_title>dotnet-trace collect-linux leaves terminal cursor hidden after tracing completes</issue_title>
<issue_description>### Description

After dotnet-trace collect-linux finishes collecting a trace and exits, the terminal cursor remains hidden. The cursor is not restored to its visible state on exit, leaving the user with an invisible cursor in their terminal session.

Steps to Reproduce

1. Open a terminal session.
2. Run dotnet-trace collect-linux -p <pid> (or any valid collect-linux invocation).
3. Wait for trace collection to complete, or stop it with Ctrl+C / Enter.
4. Observe that the terminal cursor is no longer visible after the tool exits.
5. The terminal is still functional (typing works), but the cursor is invisible.

Expected Behavior

After dotnet-trace collect-linux exits — whether through normal completion, user-initiated stop, or signal — the terminal cursor should be restored to its visible state. The tool should ensure terminal state cleanup happens on all exit paths.

Actual Behavior

The cursor remains hidden after the tool exits. Users must manually restore it by running tput cnorm or reset to get their cursor back.

Additional Context

• The tool likely hides the cursor (e.g., via ANSI escape \e[?25l) during collection for TUI/progress rendering but does not emit the corresponding show-cursor sequence (\e[?25h) on exit.
• The fix should ensure cursor restoration on all exit paths: normal exit, SIGINT, SIGTERM, and any error/panic paths.
• Consider using a cleanup guard or defer/finally pattern to guarantee terminal state is restored regardless of how the tool exits.</issue_description>

Comments on the Issue (you are @copilot in this section)

• Fixes dotnet-trace collect-linux leaves terminal cursor hidden after tracing completes #5706

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[hoyosjs]

I tested and this seems to be working correctly.

[Copilot]

Pull request overview

Fixes terminal state cleanup for dotnet-trace collect-linux by ensuring the cursor is restored after trace collection, and adds functional tests around cursor visibility behavior.

Changes:

• Restore cursor visibility in CollectLinuxCommandHandler.CollectLinux via a finally block.
• Add functional tests for cursor visibility on success, error, and redirected-output scenarios.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 4 comments.

File	Description
src/Tools/dotnet-trace/CommandLine/Commands/CollectLinuxCommand.cs	Adds cursor restoration logic in finally for collect-linux execution paths.
src/tests/dotnet-trace/CollectLinuxCommandFunctionalTests.cs	Adds tests intended to validate cursor visibility restoration behavior.

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[Copilot]

The cursor is always restored here even on paths where it was never hidden (e.g., --probe early return, or early returns before Console.CursorVisible = false), which can unexpectedly change the user's cursor state. Also, cursor visibility is still set to false unconditionally earlier, so with output redirection the cursor can be hidden but never restored. Consider only toggling cursor visibility when !Console.IsOutputRedirected, and track whether/what value you changed so the finally restores only when it was modified (ideally restoring the previous value).

Suggested change

	if (!Console.IsOutputRedirected)
	if (!Console.IsOutputRedirected && !Console.CursorVisible)

[Copilot]

exitCode is assigned but never used, which will produce a compiler warning that becomes an error in this repo (TreatWarningsAsErrors=true). Either assert on the exit code (e.g., Ok) or discard the value (e.g., _ = Run(...)).

Suggested change

	// Command should succeed
	Assert.Equal((int)ReturnCode.Ok, exitCode);

[Copilot]

exitCode is assigned but never used, which will produce a compiler warning that becomes an error in this repo (TreatWarningsAsErrors=true). Either assert on the exit code or discard the value.

[Copilot]

This test asserts the cursor remains hidden when output is redirected, but the command currently also hides the cursor unconditionally earlier. If the intent is to avoid interfering with redirected/piped output, it would be better for the command to not change cursor visibility at all when IsOutputRedirected is true; then the test should assert the cursor remains in its original state. Also, the comment referencing a specific source line number is brittle and will go stale as the file changes.

Suggested change

	int exitCode = Run(TestArgs(), console);
	// When output is redirected, the cursor restoration code in the finally block
	// should not execute, so the cursor should remain in the state set by line 104 (false)
	Assert.False(console.CursorVisible, "Cursor should remain hidden when output is redirected");
	bool initialCursorVisible = console.CursorVisible;
	int exitCode = Run(TestArgs(), console);
	// When output is redirected, the command should not change cursor visibility,
	// so the cursor should remain in its original state.
	Assert.Equal(initialCursorVisible, console.CursorVisible);