Re: [PATCH v4 2/5] stash: Add a test for when apply fails during stash branch

[Joel Teichroeb <joel@teichroeb.net>]

On Tue, Jun 13, 2017 at 12:40 PM, Junio C Hamano <gitster@pobox.com> wrote:
> Joel Teichroeb <joel@teichroeb.net> writes:
>
>> If the return value of merge recurisve is not checked, the stash could end
>> up being dropped even though it was not applied properly
>
> s/recurisve/recursive/
>
>> Signed-off-by: Joel Teichroeb <joel@teichroeb.net>
>> ---
>>  t/t3903-stash.sh | 14 ++++++++++++++
>>  1 file changed, 14 insertions(+)
>>
>> diff --git a/t/t3903-stash.sh b/t/t3903-stash.sh
>> index cc923e6335..5399fb05ca 100755
>> --- a/t/t3903-stash.sh
>> +++ b/t/t3903-stash.sh
>> @@ -656,6 +656,20 @@ test_expect_success 'stash branch should not drop the stash if the branch exists
>>       git rev-parse stash@{0} --
>>  '
>>
>> +test_expect_success 'stash branch should not drop the stash if the apply fails' '
>> +     git stash clear &&
>> +     git reset HEAD~1 --hard &&
>> +     echo foo >file &&
>> +     git add file &&
>> +     git commit -m initial &&
>
> It's not quite intuitive to call a non-root commit "initial" ;-)
>
>> +     echo bar >file &&
>> +     git stash &&
>> +     echo baz >file &&
>
> OK, so 'file' has 'foo' in HEAD, 'bar' in the stash@{0}.
>
>> +     test_when_finished "git checkout master" &&
>> +     test_must_fail git stash branch new_branch stash@{0} &&
>
> Hmph.  Do we blindly checkout new_branch out of stash@{0}^1 and
> unstash, but because 'file' in the working tree is dirty, we fail to
> apply the stash and stop?
>
> This sounds like a bug to me.  Shouldn't we be staying on 'master',
> and fail without even creating 'new_branch', when this happens?

Good point. The existing behavior is to create new_branch and check it
out. I'm not sure what the correct state should be then. Create
new_branch, checkout new_branch, fail to apply, checkout master?
Should it then delete new_branch? Is there a way instead to test
applying the stash before creating the branch without actually
applying it? Something like putting merge_recursive into some kind of
dry-run mode?

>
> In any case we should be testing what branch we are on after this
> step.  What branch should we be on after "git stash branch" fails?
>
>> +     git rev-parse stash@{0} --
>> +'
>> +
>>  test_expect_success 'stash apply shows status same as git status (relative to current directory)' '
>>       git stash clear &&
>>       echo 1 >subdir/subfile1 &&