Re: [PATCH 1/3] t7405: add a file/submodule conflict

[Elijah Newren <newren@gmail.com>]

On Mon, Jul 9, 2018 at 2:11 PM, Stefan Beller <sbeller@google.com> wrote:
> On Sat, Jul 7, 2018 at 1:44 PM Elijah Newren <newren@gmail.com> wrote:
>>
>> In the case of a file/submodule conflict, although both cannot exist at
>> the same path, we expect both to be present somewhere for the user to be
>> able to resolve the conflict with.  Add a testcase for this.
>>
>> Signed-off-by: Elijah Newren <newren@gmail.com>
>> ---
>>  t/t7405-submodule-merge.sh | 56 ++++++++++++++++++++++++++++++++++++++
>>  1 file changed, 56 insertions(+)
>>
>> diff --git a/t/t7405-submodule-merge.sh b/t/t7405-submodule-merge.sh
>> index 7bfb2f498..95fd05d83 100755
>> --- a/t/t7405-submodule-merge.sh
>> +++ b/t/t7405-submodule-merge.sh
>> @@ -279,4 +279,60 @@ test_expect_success 'recursive merge with submodule' '
>>          grep "$(cat expect3)" actual > /dev/null)
>>  '
>>
>> +# File/submodule conflict
>> +#   Commit O: <empty>
>> +#   Commit A: path (submodule)
>> +#   Commit B: path
>> +#   Expected: path/ is submodule and file contents for B's path are somewhere
>> +
>> +test_expect_success 'setup file/submodule conflict' '
>> +       test_create_repo file-submodule &&
>> +       (
>> +               cd file-submodule &&
>> +
>> +               git commit --allow-empty -m O &&
>> +
>> +               git branch A &&
>> +               git branch B &&
>> +
>> +               git checkout B &&
>> +               echo contents >path &&

This should have been 'content' rather than 'contents', given my grep below...

>> +               git add path &&
>> +               git commit -m B &&
>> +
>> +               git checkout A &&
>> +               test_create_repo path &&
>> +               (
>> +                       cd path &&
>> +
>> +                       echo hello >world &&
>
>     test_commit -C path &&
>
> or do we need a dirty submodule specifically?
> If so what is important, the untracked file or
> would changes in the index be sufficient?

Do you mean
    test_commit -C path hello
because test_commit needs at least one positional argument (which will
serve as contents, message, filename, and tag)?  Anyway, yeah, doing
this would remove the whole innermost subshell -- the cd, the echo,
the git add, and the git commit.

>
>> +                       git add world &&
>
> when observing this one in verbose mode , you may be
> asked to use 'git submodule add' instead
> https://github.com/git/git/blob/master/builtin/add.c#L323

Um, at this point, I'm adding a regular file -- not a submodule.  Also,
this git add will disappear if I use test_commit.  Perhaps you meant
one of the other 'git add's?

>
>> +                       git commit -m "submodule"
>
> Not sure if we'd need the shell it is only test_commit,
> the [submodule] add and commit, so maybe we can get away with
> 3 times -C ?

This also disappears with test_commit.

>
>> +test_expect_failure 'file/submodule conflict' '
>
> Which part fails here?

Addressed below...

>> +       test_when_finished "git -C file-submodule reset --hard" &&
>> +       (
>> +               cd file-submodule &&
>> +
>> +               git checkout A^0 &&
>> +               test_must_fail git merge B^0 >out 2>err &&

I probably shouldn't have redirected stdout and stderr here; makes it
harder for you to see what's happening, especially since I don't test
either in any way.

>> +
>> +               git ls-files -s >out &&
>> +               test_line_count = 2 out &&
>> +               git ls-files -u >out &&
>> +               test_line_count = 2 out &&
>> +
>> +               # path/ is still a submodule
>> +               test_path_is_dir path/.git &&
>> +
>> +               echo Checking if contents from B:path showed up anywhere &&
>
> This could be a comment instead?
>
>> +               grep -q content * 2>/dev/null
>
> Ah that is why we needed the specific echo above.

Yeah, if there was a handy
test_string_exists_in_some_file_in_current_directory I could have used
that, but seems like an oddly specific special test function, so I
just added an echo so someone watching the test output under --verbose
could see how far the test got.

> Sorry for being dense here, I am not quite following the last part of the test,
> as it is unclear what ought to fail in this test.

Hmm, I obviously wasn't nearly as clear as I thought I was.  Thinking
it over, two things may have thrown you off:

1) I had a typo ('content' vs. 'contents')
2) I didn't just check what was currently failing but other things
that should be true for this test.

For item 2, I've had multiple cases in the past where I created a
minimal test, only to find that if I had more carefully checked the
expected results that it would have prevented a future bug.  Also, it
was harder in the future to figure out, because I no longer remembered
the context for the test setup.  So, in this test I check the contents
of the index, make sure that the submodule is still present, and then
I finally check for the thing that currently fails:

commit B added a file called 'path'; its contents should appear
somewhere in the directory for the user to use when trying to resolve
the failed merge.  It cannot appear at 'path' (there's a submodule in
the way from commit A), but it should be present somewhere, and in
particular I'd expect it in the same directory.  So, I simply grep all
files in the current directory for the string (and ignore errors about
'grep: path is a directory').

Does that help?  If so, I'll submit a reroll with the changes and a
few extra comments.