Re: Why does git-mergetool use /dev/tty?

From: Charles Bailey <charles@hashpling.org>
Date: Aug 24, 2010, 06:43 UTC
Message-ID: <20100824064306.GA18308@hashpling.org>
In-Reply-To: <3D6C7B12-FA06-4EAD-9781-5CA74FE23057@gernhardtsoftware.com>

On Mon, Aug 23, 2010 at 09:49:57PM -0400, Brian Gernhardt wrote:

Show 8 quoted lines

> git-mergetool.sh, lines 298-302:
> >     if test $last_status -ne 0; then
> >         prompt_after_failed_merge < /dev/tty || exit 1
> >     fi
> >     printf "\n"
> >     merge_file "$i" < /dev/tty > /dev/tty
> 
> Why does git-mergetool ignore the provided STDIN and STDOUT when not given a path to merge?

It doesn't deliberately ignore them, it merely loses them because what you've quoted is in the middle of a redirect, you snipped:

    files_to_merge |
    while IFS= read i
    do

mergetool is designed to be an interactive tool and didn't originally have any tests so this was a reasonable (if ugly) way to restore access to the user for the merge_file function.

This is also why all the previous test provided an explict list of files to merge, because this was the only testable way to invoke mergetool.

There's a proposed patch to save and restore the original stdin instead of assuming that there is a tty in pu: af314714.

If the current behaviour is causing an issue for you then testing this fix would be appreciated.

Thanks,

Charles.