Re: [PATCH] git-sh: Avoid sourcing scripts with git --exec-path

From: Junio C Hamano <gitster@pobox.com>
Date: Sep 29, 2017, 05:00 UTC
Message-ID: <xmqqh8vmxfoq.fsf@gitster.mtv.corp.google.com>
In-Reply-To: <20170928223134.GA30744@varnish>

Dridi Boukelmoune <dridi.boukelmoune@gmail.com> writes:

> For end users making use of a custom exec path many commands will simply
> fail. Adding git's exec path to the PATH also allows overriding git-sh-*
> scripts, not just adding commands. One can then patch a script without
> tainting their system installation of git for example.

I think the first sentence is where you went wrong. It seems that you think this ought to work:

    rm -fr $HOME/random-stuff
    mkdir $HOME/random-stuff
    echo "echo happy" >$HOME/random-stuff/git-happy
    chmod +x $HOME/random-stuff/git-happy
    GIT_EXEC_PATH=$HOME/random-stuff
    export GIT_EXEC_PATH
    # then...
    git happy

But that is not the right/officially sanctioned/kosher way to add custom git commands (adding your directory that has git-happy in it to $PATH is). GIT_EXEC_PATH is for the git-cmd binaries and scripts we ship; it always is used to find non built-in commands, and even for built-in commands, the command found via alias look-up is invoked that way.

By insisting on overriding GIT_EXEC_PATH and not populating with the stuff we ship, you'd need a workaround like your patch just to make the scripts "work" again. I have a feeling that even with your patch you wouldn't be able to make non built-in commands, unless you copy them (or write a thin wrapper that exec's the real thing).

So, instead of the two GIT_EXEC_PATH steps in the above example, you can do

	PATH=$HOME/random-stuff:$PATH

and you'll see "git happy" to work, I would think, without breaking other things.