Re: [PATCH 2/2] Rebase: Run post-checkout hook on checkout

[Orgad Shaneh <orgads@gmail.com>]

Hi Johannes,

On Fri, Dec 21, 2018 at 6:12 PM Johannes Schindelin
<Johannes.Schindelin@gmx.de> wrote:
>
> Hi Orgad,
>
> On Thu, 20 Dec 2018, orgads@gmail.com wrote:
>
> > From: Orgad Shaneh <orgads@gmail.com>
> >
> > Signed-off-by: Orgad Shaneh <orgads@gmail.com>
>
> Feel free to steal the PR description I added to your PR at
> https://github.com/git-for-windows/git/pull/1992
>
> > diff --git a/builtin/rebase.c b/builtin/rebase.c
> > index b5c99ec10c..78a09dcda2 100644
> > --- a/builtin/rebase.c
> > +++ b/builtin/rebase.c
> > @@ -530,6 +530,7 @@ static int run_specific_rebase(struct rebase_options *opts)
> >
> >  #define RESET_HEAD_DETACH (1<<0)
> >  #define RESET_HEAD_HARD (1<<1)
> > +#define RESET_HEAD_RUN_HOOK (1<<2)
> >
> >  static int reset_head(struct object_id *oid, const char *action,
> >                     const char *switch_to_branch, unsigned flags,
> > @@ -537,6 +538,7 @@ static int reset_head(struct object_id *oid, const char *action,
> >  {
> >       unsigned detach_head = flags & RESET_HEAD_DETACH;
> >       unsigned reset_hard = flags & RESET_HEAD_HARD;
> > +     unsigned run_hook = flags & RESET_HEAD_RUN_HOOK;
> >       struct object_id head_oid;
> >       struct tree_desc desc[2] = { { NULL }, { NULL } };
> >       struct lock_file lock = LOCK_INIT;
> > @@ -636,6 +638,10 @@ static int reset_head(struct object_id *oid, const char *action,
> >                       ret = update_ref(reflog_head, "HEAD", oid, NULL, 0,
> >                                        UPDATE_REFS_MSG_ON_ERR);
> >       }
> > +     if (run_hook)
> > +             run_hook_le(NULL, "post-checkout",
> > +                         oid_to_hex(orig ? orig : &null_oid),
> > +                         oid_to_hex(oid), "1", NULL);
>
> IIRC there was one `git checkout` in the scripted version that ran the
> hook, and one did not. The latter did not run it because it did not
> actually change the HEAD, but just switched branches.
>
> We could imitate that here by extending the `if (run_hook)` to `if
> (run_hook && !oideq(&head_oid, oid))`, I think. Do you agree?

Not exactly. That's what I thought, but it looks like I was wrong.
Returning to the branch is done in sequencer.c. The 2 calls to reset_head
happen on fast-forward case.

On fast-forward there is a call to reset_head with "checkout",
followed by a call
with "Fast-forwarded". I'm not sure what exactly it does, but on my test it sent
a null oid.

I did however miss the `switch-to` case, which I now added too.

- Orgad