From: Eugeniu Rosca <erosca@de.adit-jv.com>
To: "SZEDER Gábor" <szeder.dev@gmail.com>
Cc: Eugeniu Rosca <erosca@de.adit-jv.com>,
Elijah Newren <newren@gmail.com>, <gitster@pobox.com>,
<peff@peff.net>, <avarab@gmail.com>, <git@vger.kernel.org>,
Eugeniu Rosca <roscaeugeniu@gmail.com>
Subject: Re: Unreliable 'git rebase --onto'
Date: Thu, 9 Jan 2020 12:13:06 +0100 [thread overview]
Message-ID: <20200109111306.GB1349@lxhi-065.adit-jv.com> (raw)
In-Reply-To: <20200108223557.GE32750@szeder.dev>
Hi Szeder,
On Wed, Jan 08, 2020 at 11:35:57PM +0100, SZEDER Gábor wrote:
> This is a known issue with the 'am' backend of 'git rebase'.
>
> The good news is that work is already well under way to change the
> default backend from 'am' to 'merge', which will solve this issue.
> From the log message of aa523de170 (rebase: change the default backend
> from "am" to "merge", 2019-12-24):
>
> The am-backend drops information and thus limits what we can do:
> [...]
> * reduction in context from only having a few lines beyond those
> changed means that when context lines are non-unique we can apply
> patches incorrectly.[2]
> [...]
> [2] https://lore.kernel.org/git/CABPp-BGiu2nVMQY_t-rnFR5GQUz_ipyEE8oDocKeO+>
>
> Alas, there is unexpected bad news: with that commit the runtime of
> your 'git rebase --onto' command goes from <1sec to over 50secs.
> Cc-ing Elijah, author of that patch...
[$.02] I would personally take the route of regaining users' trust in
'git rebase' first, with fixing the performance penalty later on.
I was quite impressed by the recent 2.24.0 performance improvements,
which tells there might be room for improvement for `git rebase` too,
once it is fixed.
--
Best Regards,
Eugeniu
next prev parent reply other threads:[~2020-01-09 11:13 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-08 21:43 Unreliable 'git rebase --onto' Eugeniu Rosca
2020-01-08 22:35 ` SZEDER Gábor
2020-01-09 0:55 ` Elijah Newren
2020-01-09 15:03 ` SZEDER Gábor
2020-01-09 17:53 ` Elijah Newren
2020-01-21 19:18 ` [PATCH v1] rebase -i: stop checking out the tip of the branch to rebase Alban Gruin
2020-01-21 20:07 ` Elijah Newren
2020-01-22 20:24 ` Junio C Hamano
2020-01-22 20:47 ` Junio C Hamano
2020-01-24 14:45 ` Alban Gruin
2020-01-24 14:45 ` [PATCH v2] " Alban Gruin
2020-01-24 14:55 ` Alban Gruin
2020-01-24 18:12 ` Junio C Hamano
2020-01-24 15:05 ` [PATCH v3] " Alban Gruin
2020-01-24 18:30 ` Junio C Hamano
2020-02-05 14:31 ` Johannes Schindelin
2020-01-24 17:11 ` [PATCH v2] " Andrei Rybak
2020-01-09 11:13 ` Eugeniu Rosca [this message]
[not found] ` <CABPp-BHsyMOz+hi7EYoAnAWfzms7FRfwqCoarnu8H+vyDoN6SQ@mail.gmail.com>
2020-01-09 10:53 ` Unreliable 'git rebase --onto' Eugeniu Rosca
2020-01-09 18:05 ` Elijah Newren
2020-01-10 0:06 ` Eugeniu Rosca
2020-01-10 2:35 ` Elijah Newren
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