From: Derrick Stolee <stolee@gmail.com>
To: Jonathan Tan <jonathantanmy@google.com>
Cc: git@vger.kernel.org, congdanhqx@gmail.com, newren@gmail.com,
gitster@pobox.com
Subject: Re: [PATCH v3] rebase --merge: optionally skip upstreamed commits
Date: Tue, 31 Mar 2020 07:55:11 -0400 [thread overview]
Message-ID: <f6f93f52-cb7a-f2cb-aa21-51b98044b654@gmail.com> (raw)
In-Reply-To: <20200330165705.134447-1-jonathantanmy@google.com>
On 3/30/2020 12:57 PM, Jonathan Tan wrote:
>>> Add a flag to "git rebase" to allow suppression of this feature. This
>>> flag only works when using the "merge" backend.
>>
>> So this is the behavior that already exists, and you are providing a way
>> to suppress it. However, you also change the default in this patch, which
>> may surprise users expecting this behavior to continue.
>
> First of all, thanks for looking at this.
>
> I'm not changing the default - was there anything in the commit message
> that made you believe it? If yes, I could change it.
It's not your fault. My confusion is all. You make it very clear, but
I got flipped around several times while reading the patch. Here is
your message again:
> When rebasing against an upstream that has had many commits since the
> original branch was created:
>
> O -- O -- ... -- O -- O (upstream)
> \
> -- O (my-dev-branch)
>
> it must read the contents of every novel upstream commit, in addition to
> the tip of the upstream and the merge base, because "git rebase"
> attempts to exclude commits that are duplicates of upstream ones. This
> can be a significant performance hit, especially in a partial clone,
> wherein a read of an object may end up being a fetch.
So by default, it "attempts to exclude commits that are duplicates of
upstream ones." So that's the --no-keep-cherry-pick option, which is
the default.
> Add a flag to "git rebase" to allow suppression of this feature. This
> flag only works when using the "merge" backend.
Perhaps this is how I got confused. "suppression of this feature" probably
got associated with the "--no-" version of the flag in my head. But that's
not your fault. I'm probably biased from my experience with the
--no-show-forced-updates flag in "git fetch". There, the "--no-" option
disables the default behavior.
Maybe I wouldn't be as confused if the flag was reversed and called
"--no-skip-cherry-picks" or something. That direction would make it
more clear that this is a performance optimization with a possible
behavior side-effect. I doubt users will be lining up to "keep cherry-picks."
There is a reason we remove them by default, but it is also atypical
for the check to actually change the outcome.
But if we have a config option to change the default (as a follow-up)
then all of my complaints are reduced, because users will not need to
think about this very often.
> This flag changes the behavior of sequencer_make_script(), called from
> do_interactive_rebase() <- run_rebase_interactive() <-
> run_specific_rebase() <- cmd_rebase(). With this flag, limit_list()
> (indirectly called from sequencer_make_script() through
> prepare_revision_walk()) will no longer call cherry_pick_list(), and
> thus PATCHSAME is no longer set. Refraining from setting PATCHSAME both
> means that the intermediate commits in upstream are no longer read (as
> shown by the test) and means that no PATCHSAME-caused skipping of
> commits is done by sequencer_make_script(), either directly or through
> make_script_with_merges().
Perhaps the only change I would recommend for the commit message is to
be very clear about what "this flag" means. You are talking about the
"--keep-cherry-pick(s)" flag in this paragraph.
Thanks,
-Stolee
next prev parent reply other threads:[~2020-03-31 11:55 UTC|newest]
Thread overview: 78+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-09 20:55 [PATCH] rebase --merge: optionally skip upstreamed commits Jonathan Tan
2020-03-10 2:10 ` Taylor Blau
2020-03-10 15:51 ` Jonathan Tan
2020-03-10 12:17 ` Johannes Schindelin
2020-03-10 16:00 ` Jonathan Tan
2020-03-10 18:56 ` Elijah Newren
2020-03-10 22:56 ` Jonathan Tan
2020-03-12 18:04 ` Jonathan Tan
2020-03-12 22:40 ` Elijah Newren
2020-03-14 8:04 ` Elijah Newren
2020-03-17 3:03 ` Jonathan Tan
2020-03-18 17:30 ` [PATCH v2] " Jonathan Tan
2020-03-18 18:47 ` Junio C Hamano
2020-03-18 19:28 ` Jonathan Tan
2020-03-18 19:55 ` Junio C Hamano
2020-03-18 20:41 ` Elijah Newren
2020-03-18 23:39 ` Junio C Hamano
2020-03-19 0:17 ` Elijah Newren
2020-03-18 20:20 ` Junio C Hamano
2020-03-26 17:50 ` Jonathan Tan
2020-03-26 19:17 ` Elijah Newren
2020-03-26 19:27 ` Junio C Hamano
2020-03-29 10:12 ` [PATCH v2 4/4] t3402: use POSIX compliant regex(7) Đoàn Trần Công Danh
2020-03-30 4:06 ` [PATCH v3] rebase --merge: optionally skip upstreamed commits Jonathan Tan
2020-03-30 5:09 ` Junio C Hamano
2020-03-30 5:22 ` Danh Doan
2020-03-30 12:13 ` Derrick Stolee
2020-03-30 16:49 ` Junio C Hamano
2020-03-30 16:57 ` Jonathan Tan
2020-03-31 11:55 ` Derrick Stolee [this message]
2020-03-31 16:27 ` Elijah Newren
2020-03-31 18:34 ` Junio C Hamano
2020-03-31 18:43 ` Junio C Hamano
2020-04-10 22:27 ` Jonathan Tan
2020-04-11 0:06 ` Elijah Newren
2020-04-11 1:11 ` Jonathan Tan
2020-04-11 2:46 ` Elijah Newren
-- strict thread matches above, loose matches on Subject: below --
2020-03-26 7:35 [PATCH 0/3] add travis job for linux with musl libc Đoàn Trần Công Danh
2020-03-26 7:35 ` [PATCH 1/3] ci: libify logic for usage and checking CI_USER Đoàn Trần Công Danh
2020-03-26 7:35 ` [PATCH 2/3] ci: refactor docker runner script Đoàn Trần Công Danh
2020-03-26 16:06 ` Eric Sunshine
2020-03-28 17:53 ` SZEDER Gábor
2020-03-29 6:36 ` Danh Doan
2020-03-26 7:35 ` [PATCH 3/3] travis: build and test on Linux with musl libc and busybox Đoàn Trần Công Danh
2020-03-29 5:49 ` [PATCH 0/3] add travis job for linux with musl libc Junio C Hamano
2020-03-29 10:12 ` [PATCH v2 0/4] Travis + Azure jobs " Đoàn Trần Công Danh
2020-03-29 10:12 ` [PATCH v2 1/4] ci: libify logic for usage and checking CI_USER Đoàn Trần Công Danh
2020-03-29 10:12 ` [PATCH v2 2/4] ci: refactor docker runner script Đoàn Trần Công Danh
2020-04-01 21:51 ` SZEDER Gábor
2020-03-29 10:12 ` [PATCH v2 3/4] travis: build and test on Linux with musl libc and busybox Đoàn Trần Công Danh
2020-04-01 22:18 ` SZEDER Gábor
2020-04-02 1:42 ` Danh Doan
2020-04-07 14:53 ` Johannes Schindelin
2020-04-07 21:35 ` Junio C Hamano
2020-04-10 13:38 ` Johannes Schindelin
2020-03-29 16:23 ` [PATCH v2 0/4] Travis + Azure jobs for linux with musl libc Junio C Hamano
2020-04-02 13:03 ` [PATCH v3 0/6] " Đoàn Trần Công Danh
2020-04-02 13:04 ` [PATCH v3 1/6] ci: make MAKEFLAGS available inside the Docker container in the Linux32 job Đoàn Trần Công Danh
2020-04-02 13:04 ` [PATCH v3 2/6] ci/lib-docker: preserve required environment variables Đoàn Trần Công Danh
2020-04-03 8:22 ` SZEDER Gábor
2020-04-03 10:09 ` Danh Doan
2020-04-03 19:55 ` SZEDER Gábor
2020-04-02 13:04 ` [PATCH v3 3/6] ci/linux32: parameterise command to switch arch Đoàn Trần Công Danh
2020-04-02 13:04 ` [PATCH v3 4/6] ci: refactor docker runner script Đoàn Trần Công Danh
2020-04-02 13:04 ` [PATCH v3 5/6] ci/linux32: libify install-dependencies step Đoàn Trần Công Danh
2020-04-02 13:04 ` [PATCH v3 6/6] travis: build and test on Linux with musl libc and busybox Đoàn Trần Công Danh
2020-04-02 17:53 ` [PATCH v3 0/6] Travis + Azure jobs for linux with musl libc Junio C Hamano
2020-04-03 0:23 ` Danh Doan
2020-04-04 1:08 ` [PATCH v4 0/6] Travis " Đoàn Trần Công Danh
2020-04-04 1:08 ` [PATCH v4 1/6] ci: make MAKEFLAGS available inside the Docker container in the Linux32 job Đoàn Trần Công Danh
2020-04-04 1:08 ` [PATCH v4 2/6] ci/lib-docker: preserve required environment variables Đoàn Trần Công Danh
2020-04-04 1:08 ` [PATCH v4 3/6] ci/linux32: parameterise command to switch arch Đoàn Trần Công Danh
2020-04-04 1:08 ` [PATCH v4 4/6] ci: refactor docker runner script Đoàn Trần Công Danh
2020-04-04 1:08 ` [PATCH v4 5/6] ci/linux32: libify install-dependencies step Đoàn Trần Công Danh
2020-04-04 1:08 ` [PATCH v4 6/6] travis: build and test on Linux with musl libc and busybox Đoàn Trần Công Danh
2020-04-05 20:39 ` [PATCH v4 0/6] Travis jobs for linux with musl libc Junio C Hamano
2020-04-07 14:55 ` Johannes Schindelin
2020-04-07 19:25 ` Junio C Hamano
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