From: Junio C Hamano <gitster@pobox.com>
Date: Sat, 19 Jul 2008 17:28:05 GMT
Subject: Re: [PATCH] Windows: set gitexecdir = $(bindir)
Message-ID: <7vmykd238a.fsf@gitster.siamese.dyndns.org>
In-Reply-To: <200807191052.20057.johannes.sixt@telecom.at>

Johannes Sixt <johannes.sixt@telecom.at> writes:

> On Samstag, 19. Juli 2008, Junio C Hamano wrote:
>> Sorry, I am not sure if I understand what you are trying to solve.  If you
>> have ../libexec/git-core/ in GIT_EXEC_PATH (or have builtin_exec_path()
>> use it), then your installation would look like this:
>>
>> 	[[some random place]]
>>         	bin/git
>>                 libexec/git-core/git-add
>>                 libexec/git-core/git-del
>>                 libexec/git-core/git-dir
>>                 ...
>>
>> and if "git" can figure out it is "[[some random place]]/bin/git",
>> it can find its subcommands from neighbouring directory, that is still
>> inside the random place the user told the installer to use, can't it?
>
> Yes, but...
>
> Take as an example 'git pull'.
>
> - The first call to git will derive the exec-path 
> $prefix/bin/../libexec/git-core and prepend it to $PATH.
>
> - Calls to builtin git commands from inside 'git pull' will then derive the 
> exec-path $prefix/bin/../libexec/git-core/../libexec/git-core, that is 
> $prefix/libexec/libexec/git-core, and prepend it to $PATH as well. That 
> directory does not exist - usually - and it does not hurt. But it feels dirty 
> and potentially dangerous.

You run "git" with an argument "pull".  It needs to figure out where
"git-pull" is, it checks where it came from and adds ../libexec/git-core/.
Then it runs "git-pull" script.

Then the script may have a call to "git ls-files -u" or "git-merge".

 - The former case, "git" again needs to find out where "git-ls-files"
   is.

   If "git" is found as bin/git and not as libexec/git-core/git, this
   should be perfectly fine, isn't it?  Perhaps we install a duplicate
   copy there by mistake, which is what we need to fix?

 - The latter case (our scripts source git-sh-setup so they have libexec
   one in the PATH when they are started) would find "git-merge" directly
   and runs it.

In either case, the programs "git-ls-files" and "git-merge" do not need to
do the same discovery -- are we giving them enough clues when we run them
to let them avoid that?