rebase -r: always reword merge -c
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Message ID 20190426103332.9036-1-phillip.wood123@gmail.com
State New
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  • rebase -r: always reword merge -c
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Commit Message

Phillip Wood April 26, 2019, 10:33 a.m. UTC
From: Phillip Wood <phillip.wood@dunelm.org.uk>

If a merge can be fast-forwarded then make sure that we still edit the
commit message if the user specifies -c. The implementation follows the
same pattern that is used for ordinary rewords that are fast-forwarded.

Signed-off-by: Phillip Wood <phillip.wood@dunelm.org.uk>
---
 sequencer.c              |  5 +++++
 t/t3430-rebase-merges.sh | 10 ++++++++++
 2 files changed, 15 insertions(+)

Comments

Johannes Schindelin April 29, 2019, 4:14 p.m. UTC | #1
Hi Phillip,

On Fri, 26 Apr 2019, Phillip Wood wrote:

> From: Phillip Wood <phillip.wood@dunelm.org.uk>
>
> If a merge can be fast-forwarded then make sure that we still edit the
> commit message if the user specifies -c. The implementation follows the
> same pattern that is used for ordinary rewords that are fast-forwarded.
>
> Signed-off-by: Phillip Wood <phillip.wood@dunelm.org.uk>
> ---

OMG I was bitten twice by this very bug in the past week, and planned on
looking into it next week. Thanks for beating me to it.

Two comments:

> diff --git a/sequencer.c b/sequencer.c
> index 0db410d590..ff8565e7a8 100644
> --- a/sequencer.c
> +++ b/sequencer.c
> @@ -3248,6 +3248,10 @@ static int do_merge(struct repository *r,
>  		rollback_lock_file(&lock);
>  		ret = fast_forward_to(r, &commit->object.oid,
>  				      &head_commit->object.oid, 0, opts);
> +		if (flags & TODO_EDIT_MERGE_MSG) {
> +			run_commit_flags |= AMEND_MSG;
> +			goto fast_forward_edit;
> +		}
>  		goto leave_merge;
>  	}
>
> @@ -3351,6 +3355,7 @@ static int do_merge(struct repository *r,
>  		 * value (a negative one would indicate that the `merge`
>  		 * command needs to be rescheduled).
>  		 */
> +	fast_forward_edit:

It is *slightly* awkward that this is an `else` arm of an `if (ret)`, but
I do not necessarily think that it would be better to move the label
before the `if` than what you did; Your version comes out more readable,
still.

>  		ret = !!run_git_commit(r, git_path_merge_msg(r), opts,
>  				       run_commit_flags);
>
> diff --git a/t/t3430-rebase-merges.sh b/t/t3430-rebase-merges.sh
> index 4c69255ee6..3d484a3c72 100755
> --- a/t/t3430-rebase-merges.sh
> +++ b/t/t3430-rebase-merges.sh
> @@ -164,6 +164,16 @@ test_expect_success 'failed `merge <branch>` does not crash' '
>  	grep "^Merge branch ${SQ}G${SQ}$" .git/rebase-merge/message
>  '
>
> +test_expect_success 'fast-forward merge -c still rewords' '
> +	git checkout -b fast-forward-merge-c H &&
> +	set_fake_editor &&

set_fake_editor affects global state AFAIR (setting and exporting
`EDITOR`), therefore this would need to be run in a subshell, i.e.
enclosed in parentheses.

> +	FAKE_COMMIT_MESSAGE=edited GIT_SEQUENCE_EDITOR="echo merge -c H G >" \
> +		git rebase -ir @^ &&
> +	echo edited >expected &&
> +	git log --pretty=format:%B -1 >actual &&
> +	test_cmp expected actual
> +'
> +

The rest looks good, thank you!
Dscho

>  test_expect_success 'with a branch tip that was cherry-picked already' '
>  	git checkout -b already-upstream master &&
>  	base="$(git rev-parse --verify HEAD)" &&
> --
> 2.21.0
>
>
Phillip Wood April 30, 2019, 9:01 a.m. UTC | #2
Hi Dscho

On 29/04/2019 17:14, Johannes Schindelin wrote:
> Hi Phillip,
> 
> On Fri, 26 Apr 2019, Phillip Wood wrote:
> 
>> From: Phillip Wood <phillip.wood@dunelm.org.uk>
>>
>> If a merge can be fast-forwarded then make sure that we still edit the
>> commit message if the user specifies -c. The implementation follows the
>> same pattern that is used for ordinary rewords that are fast-forwarded.
>>
>> Signed-off-by: Phillip Wood <phillip.wood@dunelm.org.uk>
>> ---
> 
> OMG I was bitten twice by this very bug in the past week, and planned on
> looking into it next week. Thanks for beating me to it.
> 
> Two comments:
> 
>> diff --git a/sequencer.c b/sequencer.c
>> index 0db410d590..ff8565e7a8 100644
>> --- a/sequencer.c
>> +++ b/sequencer.c
>> @@ -3248,6 +3248,10 @@ static int do_merge(struct repository *r,
>>   		rollback_lock_file(&lock);
>>   		ret = fast_forward_to(r, &commit->object.oid,
>>   				      &head_commit->object.oid, 0, opts);
>> +		if (flags & TODO_EDIT_MERGE_MSG) {
>> +			run_commit_flags |= AMEND_MSG;
>> +			goto fast_forward_edit;
>> +		}
>>   		goto leave_merge;
>>   	}
>>
>> @@ -3351,6 +3355,7 @@ static int do_merge(struct repository *r,
>>   		 * value (a negative one would indicate that the `merge`
>>   		 * command needs to be rescheduled).
>>   		 */
>> +	fast_forward_edit:
> 
> It is *slightly* awkward that this is an `else` arm of an `if (ret)`, but
> I do not necessarily think that it would be better to move the label
> before the `if` than what you did; Your version comes out more readable,
> still.

I did wonder about adding braces but I'm not sure that makes it any 
clearer. I agree having the label before the `if (ret)` would be less 
clear as the reader has to then think what ret will be in that case to 
work out what will happen.

>>   		ret = !!run_git_commit(r, git_path_merge_msg(r), opts,
>>   				       run_commit_flags);
>>
>> diff --git a/t/t3430-rebase-merges.sh b/t/t3430-rebase-merges.sh
>> index 4c69255ee6..3d484a3c72 100755
>> --- a/t/t3430-rebase-merges.sh
>> +++ b/t/t3430-rebase-merges.sh
>> @@ -164,6 +164,16 @@ test_expect_success 'failed `merge <branch>` does not crash' '
>>   	grep "^Merge branch ${SQ}G${SQ}$" .git/rebase-merge/message
>>   '
>>
>> +test_expect_success 'fast-forward merge -c still rewords' '
>> +	git checkout -b fast-forward-merge-c H &&
>> +	set_fake_editor &&
> 
> set_fake_editor affects global state AFAIR (setting and exporting
> `EDITOR`), therefore this would need to be run in a subshell, i.e.
> enclosed in parentheses.

The other test files are not very consistent about that. I'll re-roll. 
Note that I do not export any FAKE_* variables, so later tests should 
not be affected even if the fake editor runs.

Best Wishes

Phillip
>> +	FAKE_COMMIT_MESSAGE=edited GIT_SEQUENCE_EDITOR="echo merge -c H G >" \
>> +		git rebase -ir @^ &&
>> +	echo edited >expected &&
>> +	git log --pretty=format:%B -1 >actual &&
>> +	test_cmp expected actual
>> +'
>> +
> 
> The rest looks good, thank you!
> Dscho
> 
>>   test_expect_success 'with a branch tip that was cherry-picked already' '
>>   	git checkout -b already-upstream master &&
>>   	base="$(git rev-parse --verify HEAD)" &&
>> --
>> 2.21.0
>>
>>
Johannes Schindelin April 30, 2019, 10:51 p.m. UTC | #3
Hi Phillip,

On Tue, 30 Apr 2019, Phillip Wood wrote:

> On 29/04/2019 17:14, Johannes Schindelin wrote:
> > Hi Phillip,
> >
> > On Fri, 26 Apr 2019, Phillip Wood wrote:
> >
> > >     ret = !!run_git_commit(r, git_path_merge_msg(r), opts,
> > >              run_commit_flags);
> > >
> > > diff --git a/t/t3430-rebase-merges.sh b/t/t3430-rebase-merges.sh
> > > index 4c69255ee6..3d484a3c72 100755
> > > --- a/t/t3430-rebase-merges.sh
> > > +++ b/t/t3430-rebase-merges.sh
> > > @@ -164,6 +164,16 @@ test_expect_success 'failed `merge <branch>` does not
> > > crash' '
> > >   	grep "^Merge branch ${SQ}G${SQ}$" .git/rebase-merge/message
> > >   '
> > >
> > > +test_expect_success 'fast-forward merge -c still rewords' '
> > > +	git checkout -b fast-forward-merge-c H &&
> > > +	set_fake_editor &&
> >
> > set_fake_editor affects global state AFAIR (setting and exporting
> > `EDITOR`), therefore this would need to be run in a subshell, i.e.
> > enclosed in parentheses.
>
> The other test files are not very consistent about that. I'll re-roll. Note
> that I do not export any FAKE_* variables, so later tests should not be
> affected even if the fake editor runs.

AFAIR I tried my best to avoid `set_fake_editor` altogether and instead
preferred `write_script`/`test_config core.editor` combos in t3430.

Ciao,
Dscho

Patch
diff mbox series

diff --git a/sequencer.c b/sequencer.c
index 0db410d590..ff8565e7a8 100644
--- a/sequencer.c
+++ b/sequencer.c
@@ -3248,6 +3248,10 @@  static int do_merge(struct repository *r,
 		rollback_lock_file(&lock);
 		ret = fast_forward_to(r, &commit->object.oid,
 				      &head_commit->object.oid, 0, opts);
+		if (flags & TODO_EDIT_MERGE_MSG) {
+			run_commit_flags |= AMEND_MSG;
+			goto fast_forward_edit;
+		}
 		goto leave_merge;
 	}
 
@@ -3351,6 +3355,7 @@  static int do_merge(struct repository *r,
 		 * value (a negative one would indicate that the `merge`
 		 * command needs to be rescheduled).
 		 */
+	fast_forward_edit:
 		ret = !!run_git_commit(r, git_path_merge_msg(r), opts,
 				       run_commit_flags);
 
diff --git a/t/t3430-rebase-merges.sh b/t/t3430-rebase-merges.sh
index 4c69255ee6..3d484a3c72 100755
--- a/t/t3430-rebase-merges.sh
+++ b/t/t3430-rebase-merges.sh
@@ -164,6 +164,16 @@  test_expect_success 'failed `merge <branch>` does not crash' '
 	grep "^Merge branch ${SQ}G${SQ}$" .git/rebase-merge/message
 '
 
+test_expect_success 'fast-forward merge -c still rewords' '
+	git checkout -b fast-forward-merge-c H &&
+	set_fake_editor &&
+	FAKE_COMMIT_MESSAGE=edited GIT_SEQUENCE_EDITOR="echo merge -c H G >" \
+		git rebase -ir @^ &&
+	echo edited >expected &&
+	git log --pretty=format:%B -1 >actual &&
+	test_cmp expected actual
+'
+
 test_expect_success 'with a branch tip that was cherry-picked already' '
 	git checkout -b already-upstream master &&
 	base="$(git rev-parse --verify HEAD)" &&