Child process exiting the alternate screen during shutdown takes down the terminal window on Windows #9077

Child process exiting the alternate screen during shutdown takes down the terminal window on Windows

Symptom

When a child process running in Alacritty on Windows leaves the alternate screen as part of its shutdown, the Alacritty window itself exits. Nothing is left to type at. Reproduced with an OpenTUI-based TUI, but I do not believe this is specific to that library: it looks like host behaviour on the exit sequence.

Reproduction

Same machine, same application build, two Windows terminals:

The control case matters: Windows Terminal is also ConPTY and is unaffected by the same build, which is why I read this as Alacritty-specific rather than a ConPTY-wide problem.

Both an orderly exit command and an interrupt trigger it, and no multiplexer is required.

Control

The application can be configured not to use the alternate screen, and the failure disappears:

OTUI_USE_ALTERNATE_SCREEN=0

3 of 3 runs survive in Alacritty with the epilogue visible. That confirms the exit sequence from the alternate screen is the trigger, without saying why the host reacts by closing.

What I have not established

I have the trigger, not the mechanism. I do not know whether it is the ?1049l sequence itself, its ordering relative to process exit, or how Alacritty's ConPTY handling deals with a mode change arriving during teardown. I did not capture the raw byte stream, because the failure needs the host to actually close and a capture harness under my control does not close.

Versions

• Alacritty 0.17.0 (94e7c88)
• Windows 11
• Application: @opencode/cli 2.0.28, and current dev (OpenTUI 0.5.17)

Links

• V2: TUI leaves terminal in raw mode after /exit on Windows ConPTY (Alacritty + zellij) anomalyco/opencode#55163 — original report with measurements
• Leaving the alternate screen during teardown takes down the host console on Windows ConPTY anomalyco/opentui#1687 — my own misfiled report, now corrected and closed