Re: RFC: a plugin architecture for git extensions?

From: Junio C Hamano <gitster@pobox.com>
Date: Apr 27, 2011, 23:27 UTC
Message-ID: <7vsjt35l84.fsf@alter.siamese.dyndns.org>
In-Reply-To: <20110427220748.GA19578@elie>

Jonathan Nieder <jrnieder@gmail.com> writes:

Show 17 quoted lines

> Junio C Hamano wrote:
>
>> For example, on my primary development box, I do not have any git
>> installed from distribution, but I do have git on my $PATH.  For such
>> users, "make install" should be able to find out that the right place to
>> install git-work.1 is in $HOME/some/where/man/man1 directory.
>
> Sorry to be dense, but: isn't the right place to install git-work.1
> one of
>
> 	/usr/local/share/man
> 	/usr/share/man
> 	/opt/man
> 	$HOME/man
> 	$prefix/man
>
> depending on where the git-work binary was installed?

I was thinking it, and the location git-work binary gets installed, should depend on where "git" and its subcommand binaries are installed. The word plug-in mentioned in the thread implied that whatever plugs in is not by itself full fledged thing that is useful standalone, so it seemed a very natural thing to do.

Show 5 quoted lines

> In the $prefix
> case, the same snippet in .profile that adds $prefix/bin to the $PATH
> would also say
>
> 	MANPATH=$prefix/man:$(manpath)

You are correct only if "git" the user is building is _not_ changed to look for other places for its own manpages. If "git" was built to look at somewhere else, the relationship between the output of "git --exec-path" and that location shouldn't be assumed to be ../../share/man or anything.

The layout should be discoverable, by exposing system_path(GIT_MAN_PATH) and friends (see builtin/help.c), just like we expose GIT_EXEC_PATH.

> Or is the idea to blindly install (a symlink to) git-work to $(git
> --exec-path)/ rather than a place on the $PATH?

You can call it _blindly_ if you like, but that is what I meant. "git" tells where the binary and help material for a "plugin" to be installed, so that it can find them where it expects to.

After all, I am not interested at all in adding "git pm" or other crap. I am just trying to help people write their own "make install" of a plugin project, like "git work". And writing "make uninstall" for that project should be doable with the same information I am trying to give in this thread, no?