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From: Junio C Hamano <gitster@pobox.com>
To: "Elijah Newren via GitGitGadget" <gitgitgadget@gmail.com>
Cc: git@vger.kernel.org, Derrick Stolee <derrickstolee@github.com>,
	Elijah Newren <newren@gmail.com>
Subject: Re: [PATCH v2 1/2] rebase: remove completely useless -C option
Date: Fri, 20 Jan 2023 04:05:22 -0800	[thread overview]
Message-ID: <xmqq5yd1za0t.fsf@gitster.g> (raw)
In-Reply-To: <a0f8f5fac1c3f79cd46b943e95636728677dffef.1674190573.git.gitgitgadget@gmail.com> (Elijah Newren via GitGitGadget's message of "Fri, 20 Jan 2023 04:56:12 +0000")

"Elijah Newren via GitGitGadget" <gitgitgadget@gmail.com> writes:

> From: Elijah Newren <newren@gmail.com>
>
> The `-C` option to rebase was introduced with 67dad687ad ("add -C[NUM]
> to git-am", 2007-02-08).
> ...
> As per the git-apply documentation for the `-C` option:
>     Ensure at least <n> lines of surrounding context match...When fewer
>     lines of surrounding context exist they all must match.
>
> The fact that format-patch was not passed a -U option to increase the
> number of context lines meant that there would still only be 3 lines of
> context to match on.

I am afraid that this is only less than half true.  Isn't the
intended use of -C<num> similar to how "patch --fuzz" is used?

That is, even when a patch does not cleanly apply with full context
in the incoming diff, by requiring *smaller* number of lines to
match, the diff *could* be forced to apply with reduced precision?

My read of "even if context has changed a bit" in the log of that
commit is exactly that.  And for such a use case (which I think is
the primary use case for the feature), you do not need to futz with
the patch generation side at all.

commit 67dad687ad15d26d8e26f4d27874af0bc0965ce2
Author: Michael S. Tsirkin <mst@kernel.org>
Date:   Thu Feb 8 15:57:08 2007 +0200

    add -C[NUM] to git-am
    
    Add -C[NUM] to git-am and git-rebase so that patches can be applied even
    if context has changed a bit.
    
    Signed-off-by: Michael S. Tsirkin <mst@mellanox.co.il>
    Signed-off-by: Junio C Hamano <junkio@cox.net>

  parent reply	other threads:[~2023-01-20 12:05 UTC|newest]

Thread overview: 70+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-01-19  5:36 [PATCH] rebase: mark --update-refs as requiring the merge backend Elijah Newren via GitGitGadget
2023-01-19 21:47 ` Derrick Stolee
2023-01-20  1:54   ` Elijah Newren
2023-01-20 15:27   ` Junio C Hamano
2023-01-20 16:47     ` Elijah Newren
2023-01-20  4:56 ` [PATCH v2 0/2] " Elijah Newren via GitGitGadget
2023-01-20  4:56   ` [PATCH v2 1/2] rebase: remove completely useless -C option Elijah Newren via GitGitGadget
2023-01-20  5:40     ` Eric Sunshine
2023-01-20  6:42       ` Elijah Newren
2023-01-20  9:55     ` Martin Ågren
2023-01-20 15:32       ` Elijah Newren
2023-01-20 12:05     ` Junio C Hamano [this message]
2023-01-20 15:31       ` Elijah Newren
2023-01-20 16:15         ` Junio C Hamano
2023-01-21  4:52           ` Elijah Newren
2023-01-22  0:02             ` Junio C Hamano
2023-01-20  4:56   ` [PATCH v2 2/2] rebase: mark --update-refs as requiring the merge backend Elijah Newren via GitGitGadget
2023-01-20 16:46     ` Phillip Wood
2023-01-21  1:34       ` Elijah Newren
2023-01-21  1:55   ` [PATCH v3 0/7] rebase: fix several code/testing/documentation issues around flag incompatibilities Elijah Newren via GitGitGadget
2023-01-21  1:55     ` [PATCH v3 1/7] rebase: mark --update-refs as requiring the merge backend Elijah Newren via GitGitGadget
2023-01-21  1:55     ` [PATCH v3 2/7] rebase: flag --apply and --merge as incompatible Elijah Newren via GitGitGadget
2023-01-21  1:55     ` [PATCH v3 3/7] rebase: remove --allow-empty-message from incompatible opts Elijah Newren via GitGitGadget
2023-01-21 15:09       ` Phillip Wood
2023-01-21  1:55     ` [PATCH v3 4/7] rebase: fix docs about incompatibilities with --root Elijah Newren via GitGitGadget
2023-01-21  1:55     ` [PATCH v3 5/7] rebase: add coverage of other incompatible options Elijah Newren via GitGitGadget
2023-01-21 15:20       ` Phillip Wood
2023-01-21 19:25         ` Phillip Wood
2023-01-22  5:11           ` Elijah Newren
2023-01-21  1:55     ` [PATCH v3 6/7] rebase: clarify the OPT_CMDMODE incompatibilities Elijah Newren via GitGitGadget
2023-01-21  1:55     ` [PATCH v3 7/7] rebase: fix formatting of rebase --reapply-cherry-picks option in docs Elijah Newren via GitGitGadget
2023-01-21 15:21       ` Phillip Wood
2023-01-22  6:12     ` [PATCH v4 0/9] rebase: fix several code/testing/documentation issues around flag incompatibilities Elijah Newren via GitGitGadget
2023-01-22  6:12       ` [PATCH v4 1/9] rebase: mark --update-refs as requiring the merge backend Elijah Newren via GitGitGadget
2023-01-22  6:12       ` [PATCH v4 2/9] rebase: flag --apply and --merge as incompatible Elijah Newren via GitGitGadget
2023-01-22  6:12       ` [PATCH v4 3/9] rebase: remove --allow-empty-message from incompatible opts Elijah Newren via GitGitGadget
2023-01-22  6:12       ` [PATCH v4 4/9] rebase: fix docs about incompatibilities with --root Elijah Newren via GitGitGadget
2023-01-22  6:12       ` [PATCH v4 5/9] rebase: add coverage of other incompatible options Elijah Newren via GitGitGadget
2023-01-23 20:08         ` Phillip Wood
2023-01-24  2:36           ` Elijah Newren
2023-01-24 10:27             ` Phillip Wood
2023-01-24 13:16               ` Phillip Wood
2023-01-24 14:48                 ` Junio C Hamano
2023-01-24 15:41                 ` Elijah Newren
2023-01-24 16:48                   ` Phillip Wood
2023-01-24 17:12                     ` Elijah Newren
2023-01-24 19:21                       ` Phillip Wood
2023-01-22  6:12       ` [PATCH v4 6/9] rebase: clarify the OPT_CMDMODE incompatibilities Elijah Newren via GitGitGadget
2023-01-22  6:12       ` [PATCH v4 7/9] rebase: fix formatting of rebase --reapply-cherry-picks option in docs Elijah Newren via GitGitGadget
2023-01-22  6:12       ` [PATCH v4 8/9] rebase: put rebase_options initialization in single place Elijah Newren via GitGitGadget
2023-01-22  6:12       ` [PATCH v4 9/9] rebase: provide better error message for apply options vs. merge config Elijah Newren via GitGitGadget
2023-01-23 15:56       ` [PATCH v4 0/9] rebase: fix several code/testing/documentation issues around flag incompatibilities Derrick Stolee
2023-01-24  2:05         ` Elijah Newren
2023-01-25  4:03       ` [PATCH v5 00/10] " Elijah Newren via GitGitGadget
2023-01-25  4:03         ` [PATCH v5 01/10] rebase: mark --update-refs as requiring the merge backend Elijah Newren via GitGitGadget
2023-01-25  4:03         ` [PATCH v5 02/10] rebase: flag --apply and --merge as incompatible Elijah Newren via GitGitGadget
2023-01-25  4:03         ` [PATCH v5 03/10] rebase: remove --allow-empty-message from incompatible opts Elijah Newren via GitGitGadget
2023-01-25  4:03         ` [PATCH v5 04/10] rebase: fix docs about incompatibilities with --root Elijah Newren via GitGitGadget
2023-01-25  4:03         ` [PATCH v5 05/10] rebase: fix incompatiblity checks for --[no-]reapply-cherry-picks Elijah Newren via GitGitGadget
2023-01-25 14:14           ` Phillip Wood
2023-01-25  4:03         ` [PATCH v5 06/10] rebase: add coverage of other incompatible options Elijah Newren via GitGitGadget
2023-01-25  4:03         ` [PATCH v5 07/10] rebase: clarify the OPT_CMDMODE incompatibilities Elijah Newren via GitGitGadget
2023-01-25  4:03         ` [PATCH v5 08/10] rebase: fix formatting of rebase --reapply-cherry-picks option in docs Elijah Newren via GitGitGadget
2023-01-25  4:03         ` [PATCH v5 09/10] rebase: put rebase_options initialization in single place Elijah Newren via GitGitGadget
2023-01-25  4:03         ` [PATCH v5 10/10] rebase: provide better error message for apply options vs. merge config Elijah Newren via GitGitGadget
2023-01-25 14:17         ` [PATCH v5 00/10] rebase: fix several code/testing/documentation issues around flag incompatibilities Phillip Wood
2023-01-25 16:39         ` Junio C Hamano
2023-01-25 16:48           ` Elijah Newren
2023-02-02 10:29         ` rebase --merge vs --whitespace=fix, was " Johannes Schindelin
2023-02-02 23:48           ` Elijah Newren

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