Hi Philippe
On 08/09/2021 19:14, Philippe Blain wrote:
Hi Phillip,
Le 2021-09-08 à 09:41, Phillip Wood via GitGitGadget a écrit :
From: Phillip Wood <phillip.wood@xxxxxxxxxxxxx>
The "apply" based rebase has avoided forking git checkout since
ac7f467fef ("builtin/rebase: support running "git rebase <upstream>"",
2018-08-07). The code that handles the checkout was moved into libgit
by b309a97108 ("reset: extract reset_head() from rebase", 2020-04-07)
so lets start using it for the "merge" based rebase as well. This
opens the way for us to stop calling the post-checkout hook in the
future.
While in general I think it's a good thing to avoid forking, this change
might result in behavioral differences. Any config that affects
'git checkout' but not the internal 'reset.c::reset_head' function might
play a role in the rebase UX.
One that immediately came to mind is 'submodule.recurse'. This initial
'onto'
checkout was pretty much the only part of 'git rebase' that did
something useful
for submodules, so it's kind of sad to see it regress.
Thanks for pointing that out. As a non-submodule user my question would
be is it actually useful for the initial checkout to work that way if
the rest of rebase (and the checkout for the am backend) ignores
submodules? reset.c::reset_head() just uses unpack trees like checkout
so if rebase read 'submodule.recurse' then reset_head() would work like
'git checkout' and also 'git rebase --abort' and the "reset" command in
the todo list would start checking out submodules. I'm reluctant to do
that until the merge backend also handles submodules unless there is a
good reason that such partial submodule support would help submodule users.
[That is, until
someone
takes the time to implement 'git rebase --recurse-submodules' and makes
sure *all*
code paths that touch the working tree pay attention to this flag, and
that will
probably necessitate 'git merge --recurse-submodules' first because of
the 'merge'
backend... as far as I'm aware it's on Emily's list [1], it's also on
mine but
I don't know when I'll get the time.]
Anyway, I'm not saying that we should not do what this patch is
proposing, but
I think caveats such as that should be documented in the commit message,
Yes I'll update the commit message. It should also mention that this
fixes the bug reported in [1] where a failing post-checkout hook aborts
a rebase.
Best Wishes
Phillip
[1]
https://lore.kernel.org/git/CAHr-Uu_KeAJZrd+GzymNP47iFi+dZkvVYsWQPtzT_FQrVnWTDg@xxxxxxxxxxxxxx/
and maybe
an audit of other configs that might results in behavioural differences
should be done.
Thanks,
Philippe.
[1]
https://lore.kernel.org/git/YHofmWcIAidkvJiD@xxxxxxxxxx/t/#m0229af9183a84c2367f21e82adfbd21f08aa4437
