From: Elijah Newren <newren@gmail.com>
To: git@vger.kernel.org
Cc: gitster@pobox.com, corrmage@gmail.com, avarab@gmail.com,
Johannes.Schindelin@gmx.de, sbeller@google.com,
Elijah Newren <newren@gmail.com>
Subject: [PATCH 3/3] am: avoid directory rename detection when calling recursive merge machinery
Date: Wed, 29 Aug 2018 00:06:13 -0700 [thread overview]
Message-ID: <20180829070613.11793-4-newren@gmail.com> (raw)
In-Reply-To: <20180829070613.11793-1-newren@gmail.com>
Let's say you have the following three trees, where Base is from one commit
behind either master or branch:
Base : bar_v1, foo/{file1, file2, file3}
branch: bar_v2, foo/{file1, file2}, goo/file3
master: bar_v3, foo/{file1, file2, file3}
Using git-am (or am-based rebase) to apply the changes from branch onto
master results in the following tree:
Result: bar_merged, goo/{file1, file2, file3}
This is not what users want; they did not rename foo/ -> goo/, they only
renamed one file within that directory. The reason this happens is am
constructs fake trees (via build_fake_ancestor()) of the following form:
Base_bfa : bar_v1, foo/file3
branch_bfa: bar_v2, goo/file3
Combining these two trees with master's tree:
master: bar_v3, foo/{file1, file2, file3},
You can see that merge_recursive_generic() would see branch_bfa as renaming
foo/ -> goo/, and master as just adding both foo/file1 and foo/file2. As
such, it ends up with goo/{file1, file2, file3}
The core problem is that am does not have access to the original trees; it
can only construct trees using the blobs involved in the patch. As such,
it is not safe to perform directory rename detection within am -3.
Signed-off-by: Elijah Newren <newren@gmail.com>
---
builtin/am.c | 1 +
t/t3401-rebase-and-am-rename.sh | 4 ++--
2 files changed, 3 insertions(+), 2 deletions(-)
diff --git a/builtin/am.c b/builtin/am.c
index 2fc2d1e82c..1494a9be84 100644
--- a/builtin/am.c
+++ b/builtin/am.c
@@ -1596,6 +1596,7 @@ static int fall_back_threeway(const struct am_state *state, const char *index_pa
o.branch1 = "HEAD";
their_tree_name = xstrfmt("%.*s", linelen(state->msg), state->msg);
o.branch2 = their_tree_name;
+ o.detect_directory_renames = 0;
if (state->quiet)
o.verbosity = 0;
diff --git a/t/t3401-rebase-and-am-rename.sh b/t/t3401-rebase-and-am-rename.sh
index a87df9e675..94bdfbd69c 100755
--- a/t/t3401-rebase-and-am-rename.sh
+++ b/t/t3401-rebase-and-am-rename.sh
@@ -152,7 +152,7 @@ test_expect_success 'rebase --interactive: NO directory rename' '
)
'
-test_expect_failure 'rebase (am): NO directory rename' '
+test_expect_success 'rebase (am): NO directory rename' '
test_when_finished "git -C no-dir-rename rebase --abort" &&
(
cd no-dir-rename &&
@@ -190,7 +190,7 @@ test_expect_success 'rebase --merge: NO directory rename' '
)
'
-test_expect_failure 'am: NO directory rename' '
+test_expect_success 'am: NO directory rename' '
test_when_finished "git -C no-dir-rename am --abort" &&
(
cd no-dir-rename &&
--
2.18.0.12.g97a29da30a
next prev parent reply other threads:[~2018-08-29 7:06 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-08-28 12:27 A rebase regression in Git 2.18.0 Nikolay Kasyanov
2018-08-28 13:17 ` Ævar Arnfjörð Bjarmason
2018-08-28 13:33 ` Johannes Schindelin
2018-08-28 13:46 ` Nikolay Kasyanov
2018-08-28 15:35 ` Elijah Newren
2018-08-28 16:58 ` Junio C Hamano
2018-08-29 7:06 ` [PATCH 0/3] Turn off directory rename detection in am -3 Elijah Newren
2018-08-29 7:06 ` [PATCH 1/3] t3401: add another directory rename testcase for rebase and am Elijah Newren
2018-08-29 22:12 ` Junio C Hamano
2018-08-29 23:47 ` Elijah Newren
2018-08-30 16:01 ` Junio C Hamano
2018-08-30 16:26 ` Elijah Newren
2018-08-29 7:06 ` [PATCH 2/3] merge-recursive: add ability to turn off directory rename detection Elijah Newren
2018-08-29 12:54 ` Johannes Schindelin
2018-08-29 23:00 ` Elijah Newren
2018-08-29 7:06 ` Elijah Newren [this message]
2018-08-29 12:51 ` [PATCH 3/3] am: avoid directory rename detection when calling recursive merge machinery Johannes Schindelin
2018-08-30 16:41 ` A rebase regression in Git 2.18.0 Elijah Newren
2018-08-31 10:11 ` Johannes Schindelin
2018-08-31 19:37 ` Elijah Newren
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