Re: [PATCH] grep: remove "repo" arg from non-supporting funcs

From: Stefan Beller <sbeller@google.com>
To: Jonathan Tan <jonathantanmy@google.com>
Cc: git <git@vger.kernel.org>, Brandon Williams <bmwill@google.com>,
	Heiko Voigt <hvoigt@hvoigt.net>,
	seanwbehan@riseup.net
Subject: Re: [PATCH] grep: remove "repo" arg from non-supporting funcs
Date: Tue, 27 Mar 2018 17:35:04 -0700	[thread overview]
Message-ID: <CAGZ79kYb_a3oXCPAyL=140pyQb=CmzSWx2wVVOcyXy2VPSLNZQ@mail.gmail.com> (raw)
In-Reply-To: <20180327172451.34f60c483133df629b1e8ec6@google.com>

On Tue, Mar 27, 2018 at 5:24 PM, Jonathan Tan <jonathantanmy@google.com> wrote:
> On Tue, 27 Mar 2018 16:20:25 -0700
> Stefan Beller <sbeller@google.com> wrote:
>
>> On Tue, Mar 27, 2018 at 3:58 PM, Jonathan Tan <jonathantanmy@google.com> wrote:
>> > As part of commit f9ee2fcdfa ("grep: recurse in-process using 'struct
>> > repository'", 2017-08-02), many functions in builtin/grep.c were
>> > converted to also take "struct repository *" arguments. Among them were
>> > grep_object() and grep_objects().
>> >
>> > However, at least grep_objects() was converted incompletely - it calls
>> > gitmodules_config_oid(), which references the_repository.
>> >
>> > But it turns out that the conversion was extraneous anyway - there has
>> > been no user-visible effect - because grep_objects() is never invoked
>> > except with the_repository.
>> >
>> > Revert the changes to grep_objects() and grep_object() (which conversion
>> > is also extraneous) to show that both these functions do not support
>> > repositories other than the_repository.
>>
>> I'd rather convert gitmodules_config_oid instead of reverting the other
>> functions into a world without an arbitrary repository object.
>
> I don't really think of it as a reversion, since grep_objects() didn't
> fully support repos other than the_repository anyway.
>
> Besides that, that's fine, but then:
>
>  (1) You would have to explain both in the gitmodules_config_oid() and
>      in this patch why "gitmodules_config_oid(...)" ->
>      "gitmodules_config_oid(repo, ...)" and "submodule_free()" ->
>      "submodule_free(repo)" are safe, since they have different behavior
>      upon first glance. (They have the same behavior only because
>      grep_objects() is always called with the_repository.) I was trying
>      to explain this in as clear a way as possible, by showing (with
>      code) that grep_objects() only works with, and is only called with,
>      the_repository.
>  (2) The code path where repo != the_repository would still never be
>      exercised, and I prefer to not have such code paths.
>
> I don't feel too strongly about (1), since they just concern commit
> messages, of which there are many valid opinions on how to write them. I
> feel a bit more strongly about (2), but can concede my point if the
> project is OK with a code path not being exercised.

Ok. I admit not having looked at the code beforehand, and I was
just arguing based on intuition. Turns out I was wrong.

I thought that we'd have to have arbitrary repos for proper submodule
recursion, but this specific code is for grepping thru given tree objects,
which for now is assumed that the user can only give trees of
the_repository and we'd error out in case of a submodule tree.
Makes sense.

In that case, I agree with your patch. Thanks for writing it.
I'll take it into the series.

Thanks,
Stefan