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From: "Ævar Arnfjörð Bjarmason" <avarab@gmail.com>
To: Elijah Newren via GitGitGadget <gitgitgadget@gmail.com>
Cc: git@vger.kernel.org, Jeff King <peff@peff.net>,
	Jonathan Nieder <jrnieder@gmail.com>,
	Sergey Organov <sorganov@gmail.com>,
	Bagas Sanjaya <bagasdotme@gmail.com>,
	Neeraj Singh <nksingh85@gmail.com>,
	Johannes Altmanninger <aclopte@gmail.com>,
	Elijah Newren <newren@gmail.com>
Subject: Re: [PATCH v4 01/10] show, log: provide a --remerge-diff capability
Date: Tue, 01 Feb 2022 10:09:39 +0100	[thread overview]
Message-ID: <220201.86zgnb9bf9.gmgdl@evledraar.gmail.com> (raw)
In-Reply-To: <0b94724311df34dd10debd43c466695ed406d790.1642792341.git.gitgitgadget@gmail.com>


On Fri, Jan 21 2022, Elijah Newren via GitGitGadget wrote:

> From: Elijah Newren <newren@gmail.com>
> [...]
>  ifdef::git-log[]
> ---diff-merges=(off|none|on|first-parent|1|separate|m|combined|c|dense-combined|cc)::
> +--diff-merges=(off|none|on|first-parent|1|separate|m|combined|c|dense-combined|cc|remerge|r)::
>  --no-diff-merges::
>  	Specify diff format to be used for merge commits. Default is
>  	{diff-merges-default} unless `--first-parent` is in use, in which case
> @@ -64,6 +64,14 @@ ifdef::git-log[]
>  	each of the parents. Separate log entry and diff is generated
>  	for each parent.
>  +
> +--diff-merges=remerge:::
> +--diff-merges=r:::
> +--remerge-diff:::
> +	With this option, two-parent merge commits are remerged to
> +	create a temporary tree object -- potentially containing files
> +	with conflict markers and such.  A diff is then shown between
> +	that temporary tree and the actual merge commit.
> ++

Re some previous discussion. I really think we should add something like
this paragraph to this:
    
    The output emitted when this option is used is subject to change, and so
    is its interaction with other options (unless explicitly
    documented). I.e. many of the same caveats as the "OUTPUT STABILITY" in
    the linkgit:git-range-diff[1] documentation describes apply here. In
    particular other diff filtering options, pathspec limitations etc. may
    not produce the expected results, as some of those may apply to the
    "real" diff of the merge, and not on the generated "remerge-diff".

I think that would nicely give us permission to develop this further
without having to think about all the option interaction etc.

This is really useful right now, but I'd hate for it to get merged with
some bug/behavior that's not obvious to us now, and it being hard to fix
that because we'd have to consider the implicitly promised backwards
compatibility.

>  	int saved_dcctc = 0;
> +	struct tmp_objdir *remerge_objdir = NULL;
> +
> +	if (rev->remerge_diff) {
> +		remerge_objdir = tmp_objdir_create("remerge-diff");
> +		if (!remerge_objdir)
> +			die(_("unable to create temporary object directory"));

I guess the s/die_errno/die/ here is better for now as we won't report
the wrong errno, but also lose the common case of errno being right. But
that can be fixed up with some other series to the tmp-objdir API.

> [...]
> +# This test is ort-specific
> +test "${GIT_TEST_MERGE_ALGORITHM:-ort}" = ort || {
> +	skip_all="GIT_TEST_MERGE_ALGORITHM != ort"
> +	test_done
> +}

FWIW this is still on a more complex pattern that it needs to be, see
this v1 discussion (which you seemed to ack):

https://lore.kernel.org/git/CABPp-BE+4rZNP-5mT2MNOWR6y6BgEG6mt1r_qcrZtarom6aGsw@mail.gmail.com/

  reply	other threads:[~2022-02-01  9:35 UTC|newest]

Thread overview: 113+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-12-21 18:05 [PATCH 0/9] Add a new --remerge-diff capability to show & log Elijah Newren via GitGitGadget
2021-12-21 18:05 ` [PATCH 1/9] tmp_objdir: add a helper function for discarding all contained objects Elijah Newren via GitGitGadget
2021-12-21 23:26   ` Junio C Hamano
2021-12-21 23:51     ` Elijah Newren
2021-12-22  6:23       ` Junio C Hamano
2021-12-25  2:29         ` Elijah Newren
2021-12-21 18:05 ` [PATCH 2/9] ll-merge: make callers responsible for showing warnings Elijah Newren via GitGitGadget
2021-12-21 21:19   ` Ævar Arnfjörð Bjarmason
2021-12-21 21:57     ` Elijah Newren
2021-12-21 23:02       ` Ævar Arnfjörð Bjarmason
2021-12-21 23:15         ` Elijah Newren
2021-12-21 23:44   ` Junio C Hamano
2021-12-23 18:26     ` Elijah Newren
2021-12-21 18:05 ` [PATCH 3/9] merge-ort: capture and print ll-merge warnings in our preferred fashion Elijah Newren via GitGitGadget
2021-12-22  0:00   ` Junio C Hamano
2021-12-23 18:36     ` Elijah Newren
2021-12-21 18:05 ` [PATCH 4/9] merge-ort: mark a few more conflict messages as omittable Elijah Newren via GitGitGadget
2021-12-22  0:06   ` Junio C Hamano
2021-12-23 18:38     ` Elijah Newren
2021-12-21 18:05 ` [PATCH 5/9] merge-ort: make path_messages available to external callers Elijah Newren via GitGitGadget
2021-12-21 18:05 ` [PATCH 6/9] diff: add ability to insert additional headers for paths Elijah Newren via GitGitGadget
2021-12-22  0:24   ` Junio C Hamano
2021-12-25  2:35     ` Elijah Newren
2021-12-21 18:05 ` [PATCH 7/9] merge-ort: format messages slightly different for use in headers Elijah Newren via GitGitGadget
2021-12-21 18:05 ` [PATCH 8/9] show, log: provide a --remerge-diff capability Elijah Newren via GitGitGadget
2021-12-21 21:23   ` Ævar Arnfjörð Bjarmason
2021-12-21 22:18     ` Elijah Newren
2021-12-21 18:05 ` [PATCH 9/9] doc/diff-options: explain the new --remerge-diff option Elijah Newren via GitGitGadget
2021-12-21 21:28   ` Ævar Arnfjörð Bjarmason
2021-12-21 22:24     ` Elijah Newren
2021-12-21 23:47       ` Ævar Arnfjörð Bjarmason
2021-12-22 19:05         ` Elijah Newren
2021-12-21 23:20 ` [PATCH 0/9] Add a new --remerge-diff capability to show & log Junio C Hamano
2021-12-21 23:43   ` Elijah Newren
2021-12-22  0:33 ` Junio C Hamano
2021-12-25  7:59 ` [PATCH v2 0/8] " Elijah Newren via GitGitGadget
2021-12-25  7:59   ` [PATCH v2 1/8] show, log: provide a --remerge-diff capability Elijah Newren via GitGitGadget
2021-12-28 10:56     ` Johannes Altmanninger
2021-12-28 22:34       ` Elijah Newren
2021-12-28 23:01         ` brian m. carlson
2021-12-28 23:45           ` Elijah Newren
2021-12-25  7:59   ` [PATCH v2 2/8] log: clean unneeded objects during `log --remerge-diff` Elijah Newren via GitGitGadget
2021-12-25  7:59   ` [PATCH v2 3/8] ll-merge: make callers responsible for showing warnings Elijah Newren via GitGitGadget
2021-12-28 10:56     ` Johannes Altmanninger
2021-12-28 19:37       ` Elijah Newren
2021-12-28 22:05         ` Johannes Altmanninger
2021-12-25  7:59   ` [PATCH v2 4/8] merge-ort: capture and print ll-merge warnings in our preferred fashion Elijah Newren via GitGitGadget
2021-12-25  7:59   ` [PATCH v2 5/8] merge-ort: mark a few more conflict messages as omittable Elijah Newren via GitGitGadget
2021-12-25  7:59   ` [PATCH v2 6/8] merge-ort: format messages slightly different for use in headers Elijah Newren via GitGitGadget
2021-12-26 18:30     ` In-tree strbuf "in-place" search/replace (was: [PATCH v2 6/8] merge-ort: format messages slightly different for use in headers) Ævar Arnfjörð Bjarmason
2021-12-28 10:56     ` [PATCH v2 6/8] merge-ort: format messages slightly different for use in headers Johannes Altmanninger
2021-12-28 21:48       ` Elijah Newren
2021-12-25  7:59   ` [PATCH v2 7/8] diff: add ability to insert additional headers for paths Elijah Newren via GitGitGadget
2021-12-28 10:57     ` Johannes Altmanninger
2021-12-28 21:09       ` Elijah Newren
2021-12-29  0:16         ` Johannes Altmanninger
2021-12-30 22:04           ` Elijah Newren
2021-12-31  3:07             ` Johannes Altmanninger
2021-12-25  7:59   ` [PATCH v2 8/8] show, log: include conflict/warning messages in --remerge-diff headers Elijah Newren via GitGitGadget
2021-12-28 10:57     ` Johannes Altmanninger
2021-12-28 23:42       ` Elijah Newren
2021-12-26 21:52   ` [PATCH v2 0/8] Add a new --remerge-diff capability to show & log Ævar Arnfjörð Bjarmason
2021-12-27 21:11     ` Elijah Newren
2022-01-10 15:48       ` Ævar Arnfjörð Bjarmason
2021-12-28 10:55   ` Johannes Altmanninger
2021-12-30 23:36   ` [PATCH v3 0/9] " Elijah Newren via GitGitGadget
2021-12-30 23:36     ` [PATCH v3 1/9] show, log: provide a --remerge-diff capability Elijah Newren via GitGitGadget
2022-01-19 15:49       ` Ævar Arnfjörð Bjarmason
2022-01-20  2:31         ` Elijah Newren
2022-01-20  7:53           ` Elijah Newren
2022-01-19 16:01       ` Ævar Arnfjörð Bjarmason
2022-01-20  2:33         ` Elijah Newren
2021-12-30 23:36     ` [PATCH v3 2/9] log: clean unneeded objects during `log --remerge-diff` Elijah Newren via GitGitGadget
2021-12-30 23:36     ` [PATCH v3 3/9] ll-merge: make callers responsible for showing warnings Elijah Newren via GitGitGadget
2022-01-19 16:41       ` Ævar Arnfjörð Bjarmason
2022-01-20  3:29         ` Elijah Newren
2021-12-30 23:36     ` [PATCH v3 4/9] merge-ort: capture and print ll-merge warnings in our preferred fashion Elijah Newren via GitGitGadget
2021-12-30 23:36     ` [PATCH v3 5/9] merge-ort: mark a few more conflict messages as omittable Elijah Newren via GitGitGadget
2021-12-30 23:36     ` [PATCH v3 6/9] merge-ort: format messages slightly different for use in headers Elijah Newren via GitGitGadget
2021-12-30 23:36     ` [PATCH v3 7/9] diff: add ability to insert additional headers for paths Elijah Newren via GitGitGadget
2021-12-30 23:36     ` [PATCH v3 8/9] show, log: include conflict/warning messages in --remerge-diff headers Elijah Newren via GitGitGadget
2022-01-19 16:19       ` Ævar Arnfjörð Bjarmason
2022-01-21  2:16         ` Elijah Newren
2022-01-21 16:55           ` Elijah Newren
2021-12-30 23:36     ` [PATCH v3 9/9] merge-ort: mark conflict/warning messages from inner merges as omittable Elijah Newren via GitGitGadget
2021-12-31  8:46     ` [PATCH v3 0/9] Add a new --remerge-diff capability to show & log Junio C Hamano
2022-01-21 19:12     ` [PATCH v4 00/10] " Elijah Newren via GitGitGadget
2022-01-21 19:12       ` [PATCH v4 01/10] show, log: provide a --remerge-diff capability Elijah Newren via GitGitGadget
2022-02-01  9:09         ` Ævar Arnfjörð Bjarmason [this message]
2022-02-01 16:40           ` Elijah Newren
2022-01-21 19:12       ` [PATCH v4 02/10] log: clean unneeded objects during `log --remerge-diff` Elijah Newren via GitGitGadget
2022-02-01  9:35         ` Ævar Arnfjörð Bjarmason
2022-02-01 16:54           ` Elijah Newren
2022-02-02 11:17             ` Ævar Arnfjörð Bjarmason
2022-01-21 19:12       ` [PATCH v4 03/10] ll-merge: make callers responsible for showing warnings Elijah Newren via GitGitGadget
2022-01-21 19:12       ` [PATCH v4 04/10] merge-ort: capture and print ll-merge warnings in our preferred fashion Elijah Newren via GitGitGadget
2022-01-21 19:12       ` [PATCH v4 05/10] merge-ort: mark a few more conflict messages as omittable Elijah Newren via GitGitGadget
2022-01-21 19:12       ` [PATCH v4 06/10] merge-ort: format messages slightly different for use in headers Elijah Newren via GitGitGadget
2022-01-21 19:12       ` [PATCH v4 07/10] diff: add ability to insert additional headers for paths Elijah Newren via GitGitGadget
2022-01-21 19:12       ` [PATCH v4 08/10] show, log: include conflict/warning messages in --remerge-diff headers Elijah Newren via GitGitGadget
2022-01-21 19:12       ` [PATCH v4 09/10] merge-ort: mark conflict/warning messages from inner merges as omittable Elijah Newren via GitGitGadget
2022-01-21 19:12       ` [PATCH v4 10/10] diff-merges: avoid history simplifications when diffing merges Elijah Newren via GitGitGadget
2022-02-02  2:37       ` [PATCH v5 00/10] Add a new --remerge-diff capability to show & log Elijah Newren via GitGitGadget
2022-02-02  2:37         ` [PATCH v5 01/10] show, log: provide a --remerge-diff capability Elijah Newren via GitGitGadget
2022-02-02  2:37         ` [PATCH v5 02/10] log: clean unneeded objects during `log --remerge-diff` Elijah Newren via GitGitGadget
2022-02-02  2:37         ` [PATCH v5 03/10] ll-merge: make callers responsible for showing warnings Elijah Newren via GitGitGadget
2022-02-02  2:37         ` [PATCH v5 04/10] merge-ort: capture and print ll-merge warnings in our preferred fashion Elijah Newren via GitGitGadget
2022-02-02  2:37         ` [PATCH v5 05/10] merge-ort: mark a few more conflict messages as omittable Elijah Newren via GitGitGadget
2022-02-02  2:37         ` [PATCH v5 06/10] merge-ort: format messages slightly different for use in headers Elijah Newren via GitGitGadget
2022-02-02  2:37         ` [PATCH v5 07/10] diff: add ability to insert additional headers for paths Elijah Newren via GitGitGadget
2022-02-02  2:37         ` [PATCH v5 08/10] show, log: include conflict/warning messages in --remerge-diff headers Elijah Newren via GitGitGadget
2022-02-02  2:37         ` [PATCH v5 09/10] merge-ort: mark conflict/warning messages from inner merges as omittable Elijah Newren via GitGitGadget
2022-02-02  2:37         ` [PATCH v5 10/10] diff-merges: avoid history simplifications when diffing merges Elijah Newren via GitGitGadget

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