tui: Only query keyboard enhancement support once #6160
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We query the host terminal emulator to check whether it supports the keyboard enhancement protocol after entering raw mode on startup. We only need to check this value once though, so we can store the result in a OnceCell to prevent repeated queries. The query for keyboard enhancement support times out and fails when suspending (C-z) and resuming (`fg`) which can cause delays and leaves sequences in the terminal after Helix suspends or exits. Caching in the OnceCell prevents this behavior.
the-mikedavis
added
C-bug
| if matches!(terminal::supports_keyboard_enhancement(), Ok(true)) { | ||
| execute!(stdout, PopKeyboardEnhancementFlags)?; | ||
| } | ||
| // Ignore errors on disabling, this might trigger on windows if we call | ||
| // disable without calling enable previously | ||
| let _ = execute!(stdout, DisableMouseCapture); | ||
| let _ = execute!(stdout, PopKeyboardEnhancementFlags); |
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Ideally we would check terminal.supports_keyboard_enhancement_protocol() here but it's complicated to pass in values from Application because this function is set as a panic handler. We might be able to pass in just the boolean for whether keyboard enhancement is supported. I will check on some different terminals to see if it works to just send this PopKeyboardEnhancementFlags always though
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I gave this a test with Kitty, WezTerm (with enhanced keyboard protocol disabled), Alacritty and the default login terminal for my linux machine and it seems to not make a difference - the terminal ignores the escape sequence when it doesn't recognize it
| @@ -62,6 +64,7 @@ where | |||
| CrosstermBackend { | |||
| buffer, | |||
| capabilities: Capabilities::from_env_or_default(), | |||
| supports_keyboard_enhancement_protocol: OnceCell::new(), | |||
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This value is not included in Capabilities because the tty needs to be in raw mode to perform the query and the backend is created before raw mode is enabled
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#6149 would alternatively be solved by #6170 but we will want similar behavior in the future for checking synchronized output support as well (#731) EDIT: it looks like #6149 can also happen when resuming the process with |
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Superseded by #6194 which should make it easier to add other queries in the future |
We query the host terminal emulator to check whether it supports the keyboard enhancement protocol after entering raw mode on startup. We only need to check this value once though, so we can store the result in a OnceCell to prevent repeated queries. The query for keyboard enhancement support times out and fails when suspending (C-z) and resuming (
fg) which can cause delays and leaves sequences in the terminal after Helix suspends or exits. Caching in the OnceCell prevents this behavior.Fixes #6149