From: Junio C Hamano <gitster@pobox.com>
Date: Tue, 14 Apr 2015 17:17:26 GMT
Subject: Re: PATH modifications for git-hook processes
Message-ID: <xmqqk2xe39zt.fsf@gitster.dls.corp.google.com>
In-Reply-To: <CAKuTQSGEmHHr-c+Tc2jM-JPkx6+_f3gp8Zjj8EuQy_e4=PvMzg@mail.gmail.com>

Matthew Rothenberg <mroth@khanacademy.org> writes:

>  - what is the expected PATH modification behavior for subprocesses of
> git-hooks? Is this documented anywhere?
>  - what would be causing /usr/local/bin to be prepended here, and can
> it be adjusted via preference?

This is not limited to hooks and very much deliberate, I think.  In
order to make sure anything that is called from "git" wrapper gets
picked up from GIT_EXEC_PATH so that the matching version of the git
subprogram is used, "git <cmd>" does this before running "git-<cmd>"
(in git.c):

	/*
	 * We use PATH to find git commands, but we prepend some higher
	 * precedence paths: the "--exec-path" option, the GIT_EXEC_PATH
	 * environment, and the $(gitexecdir) from the Makefile at build
	 * time.
	 */
	setup_path();

And setup_path() is defined in exec_cmd.c to start the new PATH with
git-exec-path, and then the path to the running "git" itself, and
then finally the external PATH.