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From: Jeff King <peff@peff.net>
To: Elijah Newren <newren@gmail.com>
Cc: git@vger.kernel.org, Junio C Hamano <gitster@pobox.com>
Subject: Re: [PATCH v2] merge-recursive: fix the diff3 common ancestor label for virtual commits
Date: Tue, 1 Oct 2019 10:49:41 -0400	[thread overview]
Message-ID: <20191001144940.GH10875@sigill.intra.peff.net> (raw)
In-Reply-To: <20191001065849.29491-1-newren@gmail.com>

On Mon, Sep 30, 2019 at 11:58:49PM -0700, Elijah Newren wrote:

> In commit 743474cbfa8b ("merge-recursive: provide a better label for
> diff3 common ancestor", 2019-08-17), the label for the common ancestor
> was changed from always being
> 
>          "merged common ancestors"
> 
> to instead be based on the number of merge bases:
> 
>     >=2: "merged common ancestors"
>       1: <abbreviated commit hash>
>       0: "<empty tree>"
> 
> Unfortunately, this did not take into account that when we have a single
> merge base, that merge base could be fake or constructed.  In such
> cases, this resulted in a label of "00000000".  Of course, the previous
> label of "merged common ancestors" was also misleading for this case.

Yeah, I agree the original was not great, either, but the "0000000"
looked like a bug to me. Hey, at least we didn't segfault! :)

> Since we have an API that is explicitly about creating fake merge base
> commits in merge_recursive_generic(), we should provide a better label
> when using that API with one merge base.  So, when
> merge_recursive_generic() is called with one merge base, set the label
> to:
> 
>          "constructed merge base"

That makes perfect sense to me. Thanks for the quick turnaround.

> Changes since v1:
>   - We only had a problem if the number of fake merge bases was exactly
>     one; update the patch to check for that and update the commit message
>     accordingly.

That makes sense. We'd still want to say "merged common ancestors" even
if one of those ancestors was fake.

>  merge-recursive.c | 7 ++++++-
>  1 file changed, 6 insertions(+), 1 deletion(-)

The patch itself looks good to me (though admittedly I'm not too
familiar with this area).

Maybe worth squashing in this test?

diff --git a/t/t6047-diff3-conflict-markers.sh b/t/t6047-diff3-conflict-markers.sh
index 3fb68e0aae..860542aad0 100755
--- a/t/t6047-diff3-conflict-markers.sh
+++ b/t/t6047-diff3-conflict-markers.sh
@@ -186,4 +186,17 @@ test_expect_success 'check multiple merge bases' '
 	)
 '
 
+test_expect_success 'rebase describes fake ancestor base' '
+	test_create_repo rebase &&
+	(
+		cd rebase &&
+		test_commit base file &&
+		test_commit master file &&
+		git checkout -b side HEAD^ &&
+		test_commit side file &&
+		test_must_fail git -c merge.conflictstyle=diff3 rebase master &&
+		grep "||||||| constructed merge base" file
+	)
+'
+
 test_done

-Peff

  reply	other threads:[~2019-10-01 14:49 UTC|newest]

Thread overview: 157+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-07-25 17:45 [PATCH 00/19] Cleanup merge API Elijah Newren
2019-07-25 17:45 ` [PATCH 01/19] merge-recursive: fix minor memory leak in error condition Elijah Newren
2019-07-25 17:45 ` [PATCH 02/19] merge-recursive: remove another implicit dependency on the_repository Elijah Newren
2019-07-25 17:45 ` [PATCH 03/19] Ensure index matches head before invoking merge machinery, round N Elijah Newren
2019-07-25 19:41   ` Johannes Schindelin
2019-07-25 19:58     ` Elijah Newren
2019-07-26 11:23       ` Johannes Schindelin
2019-07-25 17:45 ` [PATCH 04/19] merge-recursive: exit early if index != head Elijah Newren
2019-07-25 19:51   ` Johannes Schindelin
2019-07-25 20:12     ` Elijah Newren
2019-07-25 17:45 ` [PATCH 05/19] merge-recursive: don't force external callers to do our logging Elijah Newren
2019-07-25 17:45 ` [PATCH 06/19] Change call signature of write_tree_from_memory() Elijah Newren
2019-07-25 19:55   ` Johannes Schindelin
2019-07-26  4:58     ` Elijah Newren
2019-07-25 17:45 ` [PATCH 07/19] Move write_tree_from_memory() from merge-recursive to cache-tree Elijah Newren
2019-07-25 17:46 ` [PATCH 08/19] merge-recursive: fix some overly long lines Elijah Newren
2019-07-25 17:46 ` [PATCH 09/19] merge-recursive: use common name for ancestors/common/base_list Elijah Newren
2019-07-25 17:46 ` [PATCH 10/19] merge-recursive: rename 'mrtree' to 'result_tree', for clarity Elijah Newren
2019-07-25 20:02   ` Johannes Schindelin
2019-07-25 17:46 ` [PATCH 11/19] merge-recursive: rename merge_options argument to opt in header Elijah Newren
2019-07-25 17:46 ` [PATCH 12/19] merge-recursive: move some definitions around to clean up the header Elijah Newren
2019-07-25 17:46 ` [PATCH 13/19] merge-recursive: consolidate unnecessary fields in merge_options Elijah Newren
2019-07-25 17:46 ` [PATCH 14/19] merge-recursive: comment and reorder the merge_options fields Elijah Newren
2019-07-25 17:46 ` [PATCH 15/19] merge-recursive: split internal fields into a separate struct Elijah Newren
2019-07-25 20:12   ` Johannes Schindelin
2019-07-25 20:27     ` Elijah Newren
2019-07-26 11:25       ` Johannes Schindelin
2019-07-26 15:30         ` Elijah Newren
2019-07-25 17:46 ` [PATCH 16/19] merge-recursive: alphabetize include list Elijah Newren
2019-07-25 17:46 ` [PATCH 17/19] merge-recursive: rename MERGE_RECURSIVE_* to MERGE_VARIANT_* Elijah Newren
2019-07-25 17:46 ` [PATCH 18/19] merge-recursive: be consistent with assert Elijah Newren
2019-07-25 17:46 ` [PATCH 19/19] merge-recursive: provide a better label for diff3 common ancestor Elijah Newren
2019-07-25 20:28   ` Johannes Schindelin
2019-07-25 18:12 ` [PATCH 00/19] Cleanup merge API Junio C Hamano
2019-07-25 19:06   ` Elijah Newren
2019-07-25 22:50     ` Junio C Hamano
2019-07-26 14:07       ` Johannes Schindelin
2019-07-25 19:15 ` Johannes Schindelin
2019-07-26 15:15   ` Elijah Newren
2019-07-26 15:52 ` [PATCH v2 00/20] " Elijah Newren
2019-07-26 15:52   ` [PATCH v2 01/20] merge-recursive: fix minor memory leak in error condition Elijah Newren
2019-07-26 18:31     ` Junio C Hamano
2019-07-26 23:19       ` Elijah Newren
2019-07-29 14:13       ` Derrick Stolee
2019-07-26 15:52   ` [PATCH v2 02/20] merge-recursive: remove another implicit dependency on the_repository Elijah Newren
2019-07-26 18:42     ` Junio C Hamano
2019-07-26 15:52   ` [PATCH v2 03/20] Ensure index matches head before invoking merge machinery, round N Elijah Newren
2019-07-26 19:14     ` Junio C Hamano
2019-07-26 23:22       ` Elijah Newren
2019-07-26 15:52   ` [PATCH v2 04/20] merge-recursive: exit early if index != head Elijah Newren
2019-07-26 19:32     ` Junio C Hamano
2019-07-26 23:26       ` Elijah Newren
2019-07-29 15:56         ` Junio C Hamano
2019-07-26 15:52   ` [PATCH v2 05/20] merge-recursive: remove useless parameter in merge_trees() Elijah Newren
2019-07-26 19:37     ` Junio C Hamano
2019-07-26 15:52   ` [PATCH v2 06/20] merge-recursive: don't force external callers to do our logging Elijah Newren
2019-07-26 19:57     ` Junio C Hamano
2019-07-26 23:28       ` Elijah Newren
2019-07-26 15:52   ` [PATCH v2 07/20] Use write_index_as_tree() in lieu of write_tree_from_memory() Elijah Newren
2019-07-26 20:11     ` Junio C Hamano
2019-07-26 23:39       ` Elijah Newren
2019-07-29  4:46         ` Junio C Hamano
2019-07-26 15:52   ` [PATCH v2 08/20] merge-recursive: fix some overly long lines Elijah Newren
2019-07-26 15:52   ` [PATCH v2 09/20] merge-recursive: use common name for ancestors/common/base_list Elijah Newren
2019-07-26 15:52   ` [PATCH v2 10/20] merge-recursive: rename 'mrtree' to 'result_tree', for clarity Elijah Newren
2019-07-26 15:52   ` [PATCH v2 11/20] merge-recursive: rename merge_options argument to opt in header Elijah Newren
2019-07-26 15:52   ` [PATCH v2 12/20] merge-recursive: move some definitions around to clean up the header Elijah Newren
2019-07-26 15:52   ` [PATCH v2 13/20] merge-recursive: consolidate unnecessary fields in merge_options Elijah Newren
2019-07-26 15:52   ` [PATCH v2 14/20] merge-recursive: comment and reorder the merge_options fields Elijah Newren
2019-07-26 15:52   ` [PATCH v2 15/20] merge-recursive: avoid losing output and leaking memory holding that output Elijah Newren
2019-07-26 15:52   ` [PATCH v2 16/20] merge-recursive: split internal fields into a separate struct Elijah Newren
2019-07-26 15:52   ` [PATCH v2 17/20] merge-recursive: alphabetize include list Elijah Newren
2019-07-26 15:52   ` [PATCH v2 18/20] merge-recursive: rename MERGE_RECURSIVE_* to MERGE_VARIANT_* Elijah Newren
2019-07-26 15:52   ` [PATCH v2 19/20] merge-recursive: be consistent with assert Elijah Newren
2019-07-26 15:52   ` [PATCH v2 20/20] merge-recursive: provide a better label for diff3 common ancestor Elijah Newren
2019-08-15 21:40   ` [PATCH v3 00/24] Clean up merge API Elijah Newren
2019-08-15 21:40     ` [PATCH v3 01/24] merge-recursive: be consistent with assert Elijah Newren
2019-08-15 21:40     ` [PATCH v3 02/24] checkout: provide better conflict hunk description with detached HEAD Elijah Newren
2019-08-15 21:40     ` [PATCH v3 03/24] merge-recursive: enforce opt->ancestor != NULL when calling merge_trees() Elijah Newren
2019-08-16 21:05       ` Junio C Hamano
2019-08-15 21:40     ` [PATCH v3 04/24] merge-recursive: provide a better label for diff3 common ancestor Elijah Newren
2019-08-16 21:33       ` Junio C Hamano
2019-08-16 22:39         ` Elijah Newren
2019-08-15 21:40     ` [PATCH v3 05/24] merge-recursive: introduce an enum for detect_directory_renames values Elijah Newren
2019-08-15 21:40     ` [PATCH v3 06/24] merge-recursive: future-proof update_file_flags() against memory leaks Elijah Newren
2019-08-15 21:40     ` [PATCH v3 07/24] merge-recursive: remove another implicit dependency on the_repository Elijah Newren
2019-08-15 21:40     ` [PATCH v3 08/24] Ensure index matches head before invoking merge machinery, round N Elijah Newren
2019-08-15 21:40     ` [PATCH v3 09/24] merge-recursive: exit early if index != head Elijah Newren
2019-08-15 21:40     ` [PATCH v3 10/24] merge-recursive: remove useless parameter in merge_trees() Elijah Newren
2019-08-15 21:40     ` [PATCH v3 11/24] merge-recursive: don't force external callers to do our logging Elijah Newren
2019-08-15 21:40     ` [PATCH v3 12/24] cache-tree: share code between functions writing an index as a tree Elijah Newren
2019-08-16 22:01       ` Junio C Hamano
2019-08-16 22:39         ` Elijah Newren
2019-08-15 21:40     ` [PATCH v3 13/24] merge-recursive: fix some overly long lines Elijah Newren
2019-08-15 21:40     ` [PATCH v3 14/24] merge-recursive: use common name for ancestors/common/base_list Elijah Newren
2019-08-15 21:40     ` [PATCH v3 15/24] merge-recursive: rename 'mrtree' to 'result_tree', for clarity Elijah Newren
2019-08-15 21:40     ` [PATCH v3 16/24] merge-recursive: rename merge_options argument to opt in header Elijah Newren
2019-08-15 21:40     ` [PATCH v3 17/24] merge-recursive: move some definitions around to clean up the header Elijah Newren
2019-08-15 21:40     ` [PATCH v3 18/24] merge-recursive: consolidate unnecessary fields in merge_options Elijah Newren
2019-08-16 22:14       ` Junio C Hamano
2019-08-16 22:59         ` Elijah Newren
2019-08-16 23:24           ` Junio C Hamano
2019-08-15 21:40     ` [PATCH v3 19/24] merge-recursive: comment and reorder the merge_options fields Elijah Newren
2019-08-15 21:40     ` [PATCH v3 20/24] merge-recursive: avoid losing output and leaking memory holding that output Elijah Newren
2019-08-15 21:40     ` [PATCH v3 21/24] merge-recursive: split internal fields into a separate struct Elijah Newren
2019-08-16 21:19       ` SZEDER Gábor
2019-08-16 23:00         ` Elijah Newren
2019-08-16 22:17       ` Junio C Hamano
2019-08-15 21:40     ` [PATCH v3 22/24] merge-recursive: rename MERGE_RECURSIVE_* to MERGE_VARIANT_* Elijah Newren
2019-08-15 21:40     ` [PATCH v3 23/24] merge-recursive: add sanity checks for relevant merge_options Elijah Newren
2019-08-16 19:52       ` Junio C Hamano
2019-08-16 22:08         ` Elijah Newren
2019-08-16 23:15           ` Junio C Hamano
2019-08-16 19:59       ` Junio C Hamano
2019-08-16 22:09         ` Elijah Newren
2019-08-15 21:40     ` [PATCH v3 24/24] merge-recursive: alphabetize include list Elijah Newren
2019-08-17 18:41     ` [PATCH v4 00/24] Clean up merge API Elijah Newren
2019-08-17 18:41       ` [PATCH v4 01/24] merge-recursive: be consistent with assert Elijah Newren
2019-08-17 18:41       ` [PATCH v4 02/24] checkout: provide better conflict hunk description with detached HEAD Elijah Newren
2019-08-17 18:41       ` [PATCH v4 03/24] merge-recursive: enforce opt->ancestor != NULL when calling merge_trees() Elijah Newren
2019-08-17 18:41       ` [PATCH v4 04/24] merge-recursive: provide a better label for diff3 common ancestor Elijah Newren
2019-09-30 21:14         ` Jeff King
2019-09-30 21:19           ` Jeff King
2019-09-30 22:54           ` [PATCH] merge-recursive: fix the diff3 common ancestor label for virtual commits Elijah Newren
2019-10-01  6:56             ` Elijah Newren
2019-10-01  6:58             ` [PATCH v2] " Elijah Newren
2019-10-01 14:49               ` Jeff King [this message]
2019-10-01 18:17                 ` [PATCH v3] " Elijah Newren
2019-10-07  2:51                   ` Junio C Hamano
2019-10-07 15:52                     ` [PATCH] merge-recursive: fix the fix to the diff3 common ancestor label Elijah Newren
2019-10-08  2:32                       ` Junio C Hamano
2019-10-08  2:36                       ` Junio C Hamano
2019-10-08 16:16                         ` Elijah Newren
2019-08-17 18:41       ` [PATCH v4 05/24] merge-recursive: introduce an enum for detect_directory_renames values Elijah Newren
2019-08-17 18:41       ` [PATCH v4 06/24] merge-recursive: future-proof update_file_flags() against memory leaks Elijah Newren
2019-08-17 18:41       ` [PATCH v4 07/24] merge-recursive: remove another implicit dependency on the_repository Elijah Newren
2019-08-17 18:41       ` [PATCH v4 08/24] Ensure index matches head before invoking merge machinery, round N Elijah Newren
2019-09-02 23:01         ` Johannes Schindelin
2019-09-03 13:34           ` Johannes Schindelin
2019-09-03 18:17             ` Elijah Newren
2019-08-17 18:41       ` [PATCH v4 09/24] merge-recursive: exit early if index != head Elijah Newren
2019-08-17 18:41       ` [PATCH v4 10/24] merge-recursive: remove useless parameter in merge_trees() Elijah Newren
2019-08-17 18:41       ` [PATCH v4 11/24] merge-recursive: don't force external callers to do our logging Elijah Newren
2019-08-17 18:41       ` [PATCH v4 12/24] cache-tree: share code between functions writing an index as a tree Elijah Newren
2019-08-17 18:41       ` [PATCH v4 13/24] merge-recursive: fix some overly long lines Elijah Newren
2019-08-17 18:41       ` [PATCH v4 14/24] merge-recursive: use common name for ancestors/common/base_list Elijah Newren
2019-08-17 18:41       ` [PATCH v4 15/24] merge-recursive: rename 'mrtree' to 'result_tree', for clarity Elijah Newren
2019-08-17 18:41       ` [PATCH v4 16/24] merge-recursive: rename merge_options argument to opt in header Elijah Newren
2019-08-17 18:41       ` [PATCH v4 17/24] merge-recursive: move some definitions around to clean up the header Elijah Newren
2019-08-17 18:41       ` [PATCH v4 18/24] merge-recursive: consolidate unnecessary fields in merge_options Elijah Newren
2019-08-17 18:41       ` [PATCH v4 19/24] merge-recursive: comment and reorder the merge_options fields Elijah Newren
2019-08-17 18:41       ` [PATCH v4 20/24] merge-recursive: avoid losing output and leaking memory holding that output Elijah Newren
2019-08-17 18:41       ` [PATCH v4 21/24] merge-recursive: split internal fields into a separate struct Elijah Newren
2019-08-19 17:17         ` Junio C Hamano
2019-08-17 18:41       ` [PATCH v4 22/24] merge-recursive: rename MERGE_RECURSIVE_* to MERGE_VARIANT_* Elijah Newren
2019-08-17 18:41       ` [PATCH v4 23/24] merge-recursive: add sanity checks for relevant merge_options Elijah Newren
2019-08-17 18:41       ` [PATCH v4 24/24] merge-recursive: alphabetize include list Elijah Newren

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