Re: [PATCH 00/14] Make git-pull a builtin

[Paul Tan <pyokagan@gmail.com>]

Hi,

On Tue, May 19, 2015 at 3:21 AM, Junio C Hamano <gitster@pobox.com> wrote:
> Paul Tan <pyokagan@gmail.com> writes:
>
>> This series rewrites git-pull.sh into a C builtin, thus improving its
>> performance and portability. It is part of my GSoC project to rewrite git-pull
>> and git-am into builtins[2].
>
> Earlier you were worried about 'git pull' being used in many tests
> for the purpose of testing other parts of the system and not testing
> 'pull' itself.  For a program as complex as 'git pull', you may want
> to take the 'competing implementations' approach.
>
> (1) write an empty cmd_pull() that relaunches "git pull" scripted
>     porcelain from the $GIT_EXEC_PATH with given parameters, and
>     wire all the necessary bits to git.c.
>
> (2) enhance cmd_pull() a bit by bit, but keep something like this
>
>         if (getenv(GIT_USE_BUILTIN_PULL)) {
>                 /* original run_command("git-pull.sh") code */
>                 exit $?
>         }
>
>         ... your "C" version ...
>
> (3) add "GIT_USE_BUILTIN_PULL=Yes; export GIT_USE_BUILTIN_PULL" at
>     the beginning of "t55??" test scripts (but not others that rely
>     on working pull and that are not interested in catching bugs in
>     pull).
>
> (4) once cmd_pull() becomes fully operational, drop (3) and also the
>     conditional one you added in (2), and retire the environment
>     variable.  Retire the git-pull.sh script to contrib/examples/
>     boneyard.
>
> That way, you will always have a reference you can use throughout
> the development.
>
> Just a suggestion, not a requirement.

Okay, I'm trying this out in the next re-roll. I do agree that this
patch series should not touch anything in t/ at all.

One problem(?) is that putting builtins/pull.o in the BUILTIN_OBJS and
leaving git-pull.sh in SCRIPT_SH in the Makefile will generate 2
targets to ./git-pull (they will clobber each other). For GNU Make,
the last defined target will win, so in this case it just happens that
git-pull.sh will win because the build targets for the shell scripts
are defined after the build targets for the builtins, so this works in
our favor I guess.

Regards,
Paul