From: "John Cai via GitGitGadget" <gitgitgadget@gmail.com>
To: git@vger.kernel.org
Cc: "Phillip Wood" <phillip.wood123@gmail.com>,
"Junio C Hamano" <gitster@pobox.com>,
"Ævar Arnfjörð Bjarmason" <avarab@gmail.com>,
"John Cai" <johncai86@gmail.com>
Subject: [PATCH v4 0/3] rebase: update HEAD when is an oid
Date: Thu, 17 Mar 2022 19:53:45 +0000 [thread overview]
Message-ID: <pull.1226.v4.git.git.1647546828.gitgitgadget@gmail.com> (raw)
In-Reply-To: <pull.1226.v3.git.git.1647487001.gitgitgadget@gmail.com>
Fixes a bug [1] reported by Michael McClimon where rebase with oids will
erroneously update the branch HEAD points to.
1. https://lore.kernel.org/git/xmqqsfrpbepd.fsf@gitster.g/
This patch has three parts:
* a test to show the incorrect buggy behavior of rebase with a non-branch
argument
* updates rebase setup test to add some tags we will use, while swapping
out manual commit creation with the test_commit helper
* sets RESET_HARD_DETACH flag if branch is not a valid refname
changes since v3:
* fixed typos in commit message
* added a test assertion to show bug behavior
* included more replacements with test_commit
changes since v2:
* remove BUG assertion
changes since v1:
* only set RESET_HEAD_DETACH if is not a valid branch
* updated tests to use existing setup
John Cai (3):
rebase: test showing bug in rebase with non-branch
rebase: use test_commit helper in setup
rebase: set REF_HEAD_DETACH in checkout_up_to_date()
builtin/rebase.c | 2 ++
t/t3400-rebase.sh | 27 +++++++++++++--------------
2 files changed, 15 insertions(+), 14 deletions(-)
base-commit: b896f729e240d250cf56899e6a0073f6aa469f5d
Published-As: https://github.com/gitgitgadget/git/releases/tag/pr-git-1226%2Fjohn-cai%2Fjc%2Ffix-rebase-oids-v4
Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-git-1226/john-cai/jc/fix-rebase-oids-v4
Pull-Request: https://github.com/git/git/pull/1226
Range-diff vs v3:
-: ----------- > 1: cac51a949ee rebase: test showing bug in rebase with non-branch
1: f658eb00bcd ! 2: 5c40e116eba rebase: use test_commit helper in setup
@@ t/t3400-rebase.sh: test_expect_success 'prepare repository with topic branches'
git checkout -f main &&
echo Third >>A &&
git update-index A &&
+ git commit -m "Modify A." &&
+ git checkout -b side my-topic-branch &&
+- echo Side >>C &&
+- git add C &&
+- git commit -m "Add C" &&
++ test_commit --no-tag "Add C" C Side &&
+ git checkout -f my-topic-branch &&
+ git tag topic
+ '
+@@ t/t3400-rebase.sh: test_expect_success 'rebase off of the previous branch using "-"' '
+ test_expect_success 'rebase a single mode change' '
+ git checkout main &&
+ git branch -D topic &&
+- echo 1 >X &&
+- git add X &&
+- test_tick &&
+- git commit -m prepare &&
++ test_commit prepare X 1 &&
+ git checkout -b modechange HEAD^ &&
+ echo 1 >X &&
+ git add X &&
2: bd1c9537ffc ! 3: 13c5955c317 rebase: set REF_HEAD_DETACH in checkout_up_to_date()
@@ Commit message
cmd_rebase() -> checkout_up_to_date() -> reset_head() -> update_refs()
-> update_ref()
- When <branch> is not a valid branch but a sha, rebase sets the head_name
+ When <branch> is not a valid branch but an oid, rebase sets the head_name
of rebase_options to NULL. This value gets passed down this call chain
through the branch member of reset_head_opts also getting set to NULL
- all the way to update_refs(). update_refs() checks ropts.branch to
- decide whether or not to switch brancheds. If ropts.branch is NULL, it
- calls update_ref() to update HEAD. At this point however, from rebase's
- point of view, we want a detached HEAD. But, since checkout_up_to_date()
- does not set the RESET_HEAD_DETACH flag, the update_ref() call will
- deference HEAD and update the branch its pointing to, which in the above
- example is main.
+ all the way to update_refs().
+
+ Then update_refs() checks ropts.branch to decide whether or not to switch
+ branches. If ropts.branch is NULL, it calls update_ref() to update HEAD.
+ At this point however, from rebase's point of view, we want a detached
+ HEAD. But, since checkout_up_to_date() does not set the RESET_HEAD_DETACH
+ flag, the update_ref() call will deference HEAD and update the branch its
+ pointing to, which in the above example is main.
The correct behavior is that git rebase should update HEAD to $(git
rev-parse topic) without dereferencing it.
@@ Commit message
HEAD directly intead of deferencing it and updating the branch that HEAD
points to.
- Also add a test to ensure this behavior.
+ Also add a test to ensure the correct behavior.
1. https://lore.kernel.org/git/xmqqsfrpbepd.fsf@gitster.g/
- Reported-by: Michael McClimon <michael@mcclimon.org>
Signed-off-by: John Cai <johncai86@gmail.com>
## builtin/rebase.c ##
@@ builtin/rebase.c: static int checkout_up_to_date(struct rebase_options *options)
- getenv(GIT_REFLOG_ACTION_ENVIRONMENT),
- options->switch_to);
ropts.oid = &options->orig_head;
-- ropts.branch = options->head_name;
+ ropts.branch = options->head_name;
ropts.flags = RESET_HEAD_RUN_POST_CHECKOUT_HOOK;
-+ if (options->head_name)
-+ ropts.branch = options->head_name;
-+ else
++ if (!ropts.branch)
+ ropts.flags |= RESET_HEAD_DETACH;
ropts.head_msg = buf.buf;
if (reset_head(the_repository, &ropts) < 0)
@@ t/t3400-rebase.sh: test_expect_success 'switch to branch not checked out' '
git rebase main other
'
+-test_expect_success 'switch to non-branch changes branch HEAD points to' '
+test_expect_success 'switch to non-branch detaches HEAD' '
-+ git checkout main &&
-+ old_main=$(git rev-parse HEAD) &&
-+ git rebase First Second^0 &&
+ git checkout main &&
+ old_main=$(git rev-parse HEAD) &&
+ git rebase First Second^0 &&
+- test_cmp_rev HEAD main &&
+- test_cmp_rev main $(git rev-parse Second) &&
+- git symbolic-ref HEAD
+ test_cmp_rev HEAD Second &&
+ test_cmp_rev main $old_main &&
+ test_must_fail git symbolic-ref HEAD
-+'
-+
+ '
+
test_expect_success 'refuse to switch to branch checked out elsewhere' '
- git checkout main &&
- git worktree add wt &&
--
gitgitgadget
next prev parent reply other threads:[~2022-03-17 19:54 UTC|newest]
Thread overview: 41+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-03-11 5:05 [PATCH] rebase: set REF_HEAD_DETACH in checkout_up_to_date() John Cai via GitGitGadget
2022-03-11 5:33 ` Junio C Hamano
2022-03-11 5:55 ` Junio C Hamano
2022-03-11 14:14 ` John Cai
2022-03-11 15:05 ` Phillip Wood
2022-03-11 15:28 ` John Cai
2022-03-11 19:42 ` John Cai
2022-03-11 21:31 ` Phillip Wood
2022-03-11 17:24 ` [PATCH v2 0/2] rebase: update HEAD when is an oid John Cai via GitGitGadget
2022-03-11 17:24 ` [PATCH v2 1/2] rebase: use test_commit helper in setup John Cai via GitGitGadget
2022-03-13 7:50 ` Junio C Hamano
2022-03-14 10:52 ` Phillip Wood
2022-03-14 21:47 ` Junio C Hamano
2022-03-11 17:24 ` [PATCH v2 2/2] rebase: set REF_HEAD_DETACH in checkout_up_to_date() John Cai via GitGitGadget
2022-03-13 7:58 ` Junio C Hamano
2022-03-14 10:54 ` Phillip Wood
2022-03-14 14:05 ` Phillip Wood
2022-03-14 14:11 ` John Cai
2022-03-14 14:25 ` Phillip Wood
2022-03-17 3:16 ` [PATCH v3 0/2] rebase: update HEAD when is an oid John Cai via GitGitGadget
2022-03-17 3:16 ` [PATCH v3 1/2] rebase: use test_commit helper in setup John Cai via GitGitGadget
2022-03-17 13:37 ` Ævar Arnfjörð Bjarmason
2022-03-17 3:16 ` [PATCH v3 2/2] rebase: set REF_HEAD_DETACH in checkout_up_to_date() John Cai via GitGitGadget
2022-03-17 13:42 ` Ævar Arnfjörð Bjarmason
2022-03-17 15:34 ` Junio C Hamano
2022-03-17 19:53 ` John Cai via GitGitGadget [this message]
2022-03-17 19:53 ` [PATCH v4 1/3] rebase: test showing bug in rebase with non-branch John Cai via GitGitGadget
2022-03-17 21:10 ` Junio C Hamano
2022-03-17 21:37 ` Junio C Hamano
2022-03-17 22:44 ` John Cai
2022-03-17 19:53 ` [PATCH v4 2/3] rebase: use test_commit helper in setup John Cai via GitGitGadget
2022-03-18 11:14 ` Phillip Wood
2022-03-18 13:06 ` John Cai
2022-03-17 19:53 ` [PATCH v4 3/3] rebase: set REF_HEAD_DETACH in checkout_up_to_date() John Cai via GitGitGadget
2022-03-17 21:36 ` Junio C Hamano
2022-03-18 0:30 ` John Cai
2022-03-18 13:54 ` [PATCH v5 0/2] rebase: update HEAD when is an oid John Cai via GitGitGadget
2022-03-18 13:54 ` [PATCH v5 1/2] rebase: use test_commit helper in setup John Cai via GitGitGadget
2022-03-18 16:51 ` Junio C Hamano
2022-03-18 13:54 ` [PATCH v5 2/2] rebase: set REF_HEAD_DETACH in checkout_up_to_date() John Cai via GitGitGadget
2022-03-18 16:55 ` [PATCH v5 0/2] rebase: update HEAD when is an oid Junio C Hamano
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