Re: [PATCH v4 1/3] stash: add tests to ensure reflog --rewrite --updatref behavior

[John Cai <johncai86@gmail.com>]

Hi Phillip,

On 8 Mar 2022, at 5:39, Phillip Wood wrote:

> Hi John
>
> On 03/03/2022 19:12, John Cai wrote:
>> Hi Phillip,
>>
>> On 3 Mar 2022, at 12:28, Phillip Wood wrote:
>>
>>> On 03/03/2022 16:52, Ævar Arnfjörð Bjarmason wrote:
>>>>
>>>> On Thu, Mar 03 2022, Phillip Wood wrote:
>>>>
>>>>> On 02/03/2022 23:32, Junio C Hamano wrote:
>>>>>> "John Cai via GitGitGadget" <gitgitgadget@gmail.com> writes:
>>>>>> [...]
>>>>>>> +test_expect_success REFFILES 'drop stash reflog updates refs/stash with rewrite' '
>>>>>>> +	git init repo &&
>>>>>>> +	(
>>>>>>> +		cd repo &&
>>>>>>> +		setup_stash
>>>>>>> +	) &&
>>>>>> Hmph, so this is done inside the subdirectory.  The implementation
>>>>>> of the helper in this iteration does look cleaner than in the
>>>>>> previous iteration.
>>>>>> But these many references to "repo/" and "-C repo" we see below
>>>>>> makes me wonder why we do not put the whole thing inside the
>>>>>> subshell we started earlier.
>>>>>> i.e.
>>>>>> 	git init repo &&
>>>>>> 	(
>>>>>> 		cd repo &&
>>>>>> 		setup_stash_test &&
>>>>>> 		echo 9 >file &&
>>>>>> 		old=$(git rev-parse stash@{0}) &&
>>>>>> 		git stash &&
>>>>>> 		new=$(git rev-parse stash@{0}) &&
>>>>>> 		...
>>>>>> 		test_cmp expect actual
>>>>>> 	)
>>>>>>
>>>>>
>>>>> I wonder if we could avoid the subshell entirely and avoid relying on
>>>>> REFFILES (assuming we're not trying to test the implementation details
>>>>> of that refs backend) by doing something like
>>>>>
>>>>> test_expect_success 'drop stash reflog updates refs/stash with rewrite' '
>>>>> 	old=$(git rev-parse stash@{0}) &&
>>>>> 	setup_stash_test &&
>>>>> 	git rev-list -g stash >tmp &&
>>>>> 	sed /$old/d tmp >expect &&
>>>>> 	git rev-list -g stash >actual &&
>>>>> 	test_cmp expect actual
>>>>> '
>>>>
>>>> Unless I'm missing something that "rev-list -g" will emit only the RHS
>>>> of the stash logs, i.e. no "0000..." etc.
>>>>
>>>> And if we only look at that the difference with specifying the flag
>>>> isn't visible, no?
>>>
>>> Maybe I'm missing what this test is actually needs to do. I thought it just needed to check that the deleted stash is removed from the reflog and the others are unchanged. You're right that it wont show the LHS and if that is important then you need to read the log file directly.
>>
>> We had discussed this briefly in [1], but the --rewrite option for reflog delete will rewrite the LHS, which is not visible to normal ref API users. So the only way to test that this happened is to reach inside of the file.
>>
>> 1. https://lore.kernel.org/git/xmqqczjdp2g8.fsf@gitster.g/
>
> Thanks for the pointer, that was useful context that could maybe be added to the commit message to explain why the test needs to check the lhs of the reflog if you reroll.

Good point. that would be helpful context since it took me a while to figure it out myself--will re-roll, thanks!

>
> Best Wishes
>
> Phillip
>
>>>
>>> Best Wishes
>>>
>>> Phillip
>>
>> thanks,
>> John
>>
>>>
>>>
>>>>>>> +	echo 9 >repo/file &&
>>>>>>> +
>>>>>>> +	old_oid="$(git -C repo rev-parse stash@{0})" &&
>>>>>>> +	git -C repo stash &&
>>>>>>> +	new_oid="$(git -C repo rev-parse stash@{0})" &&
>>>>>>> +
>>>>>>> +	cat >expect <<-EOF &&
>>>>>>> +	$(test_oid zero) $old_oid
>>>>>>> +	$old_oid $new_oid
>>>>>>> +	EOF
>>>>>>> +	cut -d" " -f1-2 repo/.git/logs/refs/stash >actual &&
>>>>>>> +	test_cmp expect actual &&
>>>>>>> +
>>>>>>> +	git -C repo stash drop stash@{1} &&
>>>>>>> +	cut -d" " -f1-2 repo/.git/logs/refs/stash >actual &&
>>>>>>> +	cat >expect <<-EOF &&
>>>>>>> +	$(test_oid zero) $new_oid
>>>>>>> +	EOF
>>>>>>> +	test_cmp expect actual
>>>>>>> +'
>>>>>>> +
>>>>>>>     test_expect_success 'stash pop' '
>>>>>>>     	git reset --hard &&
>>>>>>>     	git stash pop &&
>>>>