From: Stefan Beller <sbeller@google.com>
To: Junio C Hamano <gitster@pobox.com>
Cc: neuling@dakosy.de, "git@vger.kernel.org" <git@vger.kernel.org>
Subject: Re: git pull --rebase should use fast forward merge if possible
Date: Wed, 29 Jun 2016 13:40:27 -0700 [thread overview]
Message-ID: <CAGZ79kYS=XWBpEBJsj95FV+j+HLxg=5xqwD73618t7ERYrKUfA@mail.gmail.com> (raw)
In-Reply-To: <xmqqtwgb52py.fsf@gitster.mtv.corp.google.com>
On Wed, Jun 29, 2016 at 10:23 AM, Junio C Hamano <gitster@pobox.com> wrote:
> Junio C Hamano <gitster@pobox.com> writes:
>
>>> Is it possible to change the behavior of "git pull
>>> --rebase=true|preserve|interactive" to use a fast forward merge if the
>>> remote branch is ahead and the local branch contains no new commits?
>>
>> Interesting. I do not think of a reason why we shouldn't.
Me neither.
>>
>> If we were still working in scripted Porcelain, it would have been a
>> five minute hack, perhaps like this.
>>
>> contrib/examples/git-pull.sh | 8 ++++++++
>> 1 file changed, 8 insertions(+)
>
> ... and if we have to work with built-ins, it becomes a lot larger
> than a five-minute hack, unfortunately.
>
> Something like this may have a chance of working ;-)
>
> builtin/pull.c | 22 ++++++++++++++++++----
> 1 file changed, 18 insertions(+), 4 deletions(-)
>
> diff --git a/builtin/pull.c b/builtin/pull.c
> index bf3fd3f..777ae56 100644
> --- a/builtin/pull.c
> +++ b/builtin/pull.c
> @@ -878,10 +878,24 @@ int cmd_pull(int argc, const char **argv, const char *prefix)
> if (merge_heads.nr > 1)
> die(_("Cannot merge multiple branches into empty head."));
> return pull_into_void(*merge_heads.sha1, curr_head);
> - } else if (opt_rebase) {
> - if (merge_heads.nr > 1)
> - die(_("Cannot rebase onto multiple branches."));
> + }
> + if (opt_rebase && merge_heads.nr > 1)
> + die(_("Cannot rebase onto multiple branches."));
> +
> + if (opt_rebase) {
> + struct commit_list *list = NULL;
> + struct commit *merge_head, *head;
> +
> + head = lookup_commit_reference(orig_head);
> + commit_list_insert(head, &list);
> + merge_head = lookup_commit_reference(merge_heads.sha1[0]);
The crashes for merge_heads.nr == 0.
(I did not inspect code further up if this is caught before, I think
it would trigger if
you and the remote are on an initial commit with no parents?)
> + if (is_descendant_of(merge_head, list)) {
> + /* we can fast-forward this without invoking rebase */
> + opt_ff = "--ff-only";
> + return run_merge();
> + }
> return run_rebase(curr_head, *merge_heads.sha1, rebase_fork_point);
> - } else
> + }
> + else
Keep the style ?
> return run_merge();
> }
> --
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next prev parent reply other threads:[~2016-06-29 20:41 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-06-29 16:18 git pull --rebase should use fast forward merge if possible neuling
2016-06-29 16:32 ` Junio C Hamano
2016-06-29 17:23 ` Junio C Hamano
2016-06-29 20:40 ` Stefan Beller [this message]
2016-06-29 20:43 ` Junio C Hamano
2016-12-01 17:59 ` Re* " Junio C Hamano
2016-12-01 18:24 ` Stefan Beller
2016-12-01 18:50 ` Junio C Hamano
2016-12-01 18:51 ` Stefan Beller
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