Re: [PATCH] editor: only save (and restore) the terminal if using a tty

[Phillip Wood <phillip.wood123@gmail.com>]

Hi Carlo

On 22/11/2021 22:28, Carlo Marcelo Arenas Belón wrote:
> If the editor is invoked without a controlling terminal, then
> saving the state and restoring it later is not very useful and
> could generate signals that the invoking process wouldn't know
> how to handle.
> 
> if git's standard output is not connected to a terminal, then
> presume there is no need to worry if the invoking terminal could
> garble it.

Checking if stdout is a terminal fixes the Eclipse case where stdout is 
a pipe or /dev/null but if git is started in the background from a 
terminal then calling isatty() will not prevent git from receiving 
SIGTTOU. For example if the user is using a gui editor then the 
following used to work

GIT_EDITOR=gedit git commit&

Now git receives SIGTTOU when the editor exits because we call 
tcsetattr() from a background process group. One can argue it does not 
make much sense to be starting git in the background but it did work 
before these changes. I think a combination of isatty() and tcgetpgrp() 
is probably the best solution.

Best Wishes

Phillip


> Reported-by: Alexander Veit <alexander.veit@gmx.net>
> Signed-off-by: Carlo Marcelo Arenas Belón <carenas@gmail.com>
> ---
>   editor.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/editor.c b/editor.c
> index 674309eed8..214e3834cb 100644
> --- a/editor.c
> +++ b/editor.c
> @@ -86,7 +86,7 @@ static int launch_specified_editor(const char *editor, const char *path,
>   		p.env = env;
>   		p.use_shell = 1;
>   		p.trace2_child_class = "editor";
> -		term_fail = save_term(1);
> +		term_fail = isatty(1) ? save_term(1) : 1;
>   		if (start_command(&p) < 0) {
>   			if (!term_fail)
>   				restore_term();
>