Re: [PATCH] refs: add option core.logAllRefUpdates = always

From: Cornelius Weig <cornelius.weig@tngtech.com>
Date: Jan 26, 2017, 14:06 UTC
Message-ID: <4faf836a-40b6-da9a-877a-3b2ce7c863df@tngtech.com>
In-Reply-To: <20170126033547.7bszipvkpi2jb4ad@sigill.intra.peff.net>

Hi Peff,

 thanks for your thoughts.

> I tried to read this patch with fresh eyes. But given the history, you
> may take my review with a grain of salt. :)

Does it mean another reviewer is needed?

> I don't think my original had tests for this, but it might be worth
> adding a test for this last bit (i.e., that an update of ORIG_HEAD does
> not write a reflog when logallrefupdates is set to "always").

Good point. I blindly copied your commit message without thinking too much about it.

> I guess the backtick fixups came from my original. It might be easier to
> see the change if they were pulled into their own patch, but it's
> probably not that big a deal.

If it's best practice to break out such changes, I'll revise it.

Show 12 quoted lines

>> @@ -2835,8 +2835,8 @@ static int log_ref_write_1(const char *refname, const unsigned char *old_sha1,
>>  {
>>  	int logfd, result, oflags = O_APPEND | O_WRONLY;
>>  
>> -	if (log_all_ref_updates < 0)
>> -		log_all_ref_updates = !is_bare_repository();
>> +	if (log_all_ref_updates == LOG_REFS_UNSET)
>> +		log_all_ref_updates = is_bare_repository() ? LOG_REFS_NONE : LOG_REFS_NORMAL;
> 
> This hunk is new, I think. The enum values are set in such a way that
> the original code would have continued to work, but I think using the
> symbolic names is an improvement.

Yes it's new.

Show 20 quoted lines

> I assume you grepped for log_all_ref_updates to find this. I see only
> one spot that now doesn't use the symbolic names. In builtin/checkout.c,
> update_refs_for_switch() checks:
> 
>   if (opts->new_branch_log && !log_all_ref_updates)
> 
> That looks buggy, as it would treat LOG_REFS_NORMAL and LOG_REFS_UNSET
> the same, and I do not see us resolving the UNSET case to a true/false
> value. But I don't think the bug is new in your patch; the default value
> was "-1" already.
>
> I doubt it can be triggered in practice, because either:
> 
>   - the config value is set in the config file, and we pick up that
>     value, whether it's "true" or "false"
> 
>   - it's unset, in which case our default would be to enable reflogs in
>     a non-bare repo. And since git-checkout would refuse to run in a
>     bare repo, we must be non-bare, and thus enabling reflogs does the
>     right thing.

That far I can follow.

> But it works quite by accident. I wonder if we should this
> "is_bare_repository" check into a function that can be called instead of
> accessing log_all_ref_updates() directly.

Are you saying that we should move the `!log_all_ref_updates` check into its own function where we should also check `is_bare_repository`? I don't see that this would win much, because as you said: checkouts in a bare repo are forbidden anyway.

Other than that, I guess it should better read `log_all_ref_update != LOG_REFS_NONE` instead of `!log_all_ref_updates`.

Show 5 quoted lines

>> +test_expect_success 'update-ref does not create reflog with --no-create-reflog if core.logAllRefUpdates=always' '
> 
> This test title is _really_ long, and will wrap in the output on
> reasonable-sized terminals. Maybe '--no-create-reflog overrides
> core.logAllRefUpdates=always' would be shorter?

Yes, I agree.

Show 10 quoted lines

>> +test_expect_success 'stdin does not create reflog when core.logAllRefUpdates=true' '
> 
> I don't mind these extra stdin tests, but IMHO they are just redundant.
> The "--stdin --create-reflog" one makes sure the option is propagated
> down via the --stdin machinery. But we know the config option is handled
> at a low level anyway.
> 
> I guess it depends on how black-box we want the testing to be. It just
> seems unlikely for a regression to be found here and not in the tests
> above.

Since these other stdin tests were around, I added this variant. But you're right: this test breaks along with the other and doesn't add add more safety. I'll remove it.

However, I realized that I have not written tests about ref updates in a bare repository. Do you think it's worthwile?

Cheers,
  Cornelius