Re: [PATCHv4 1/2] clone: respect additional configured fetch refspecs during initial fetch

From: SZEDER Gábor <szeder.dev@gmail.com>
Date: Jun 16, 2017, 17:36 UTC
Message-ID: <CAM0VKjmxtqB2zrWOW8T9O1ReWNPTZA7V3-Dei7GecB3nxVh2Dg@mail.gmail.com>
In-Reply-To: <20170614004816.GR133952@aiede.mtv.corp.google.com>

On Wed, Jun 14, 2017 at 2:48 AM, Jonathan Nieder <jrnieder@gmail.com> wrote:

Show 9 quoted lines

>> diff --git a/remote.h b/remote.h
>> index 924881169..9ad8c1085 100644
>> --- a/remote.h
>> +++ b/remote.h
>> @@ -164,6 +164,7 @@ struct ref *ref_remove_duplicates(struct ref *ref_map);
>>
>>  int valid_fetch_refspec(const char *refspec);
>>  struct refspec *parse_fetch_refspec(int nr_refspec, const char **refspec);
>> +void add_and_parse_fetch_refspec(struct remote *remote, const char *refspec);

Show 6 quoted lines

> I'm tempted to say that this one should be named add_fetch_refspec (or
> something like remote_add_refspec) --- this is the only way to add a
> fetch refspec in the public remote API, and the fact that it parses is
> an implementation detail.  The private add_fetch_refpsec that builds
> the fetch_refspec as preparation for parsing them in a batch is not
> part of the exported API.

I kind of agree, but ...

First, there is an add_push_refspec() function as well, which, just like its fetch counterpart, doesn't parse the given refspec, only appends it to remote->push_refspec. Changing add_fetch_refspec() to parse, too, would break this symmetry.

Furthermore, at the moment we have both remote->fetch_refspec (for strings) and remote->fetch (for parsed refspecs), and parsing a refspec die()s if it's bogus, therefore I think that parsing is not an implementation detail that should be hidden.

Show 5 quoted lines

> The caller adds one refspec right after calling remote_get.  I'm
> starting to wonder if this could be done more simply by having a
> variant of remote_get that allows naming an additional refspec, so
> that remote->fetch could be immutable after construction like it was
> before.  What do you think?

That's such a very specific and narrow use case that I don't think it justifies a dedicated function. I don't think remote->fetch should be immutable; I think remote->{fetch,push}_refspec and the lazy parsing of refspecs should go away. Cleaning up this corner of the remote API is beyond the scope of this patch series.

Show 8 quoted lines

> [...]
>> +     /* Not free_refspecs(), as we copied its pointers above */
>> +     free(rs);
>
> Allocating an array to put the parsed refspec in and then freeing it
> seems wasteful.  Should parse_refspec_internal be changed to take an
> output parameter so it can put the refspec into remote->fetch
> directly?

No, I found that extracting the huge body of its loop into a helper function that fills an output parameter is much more useful.

Show 12 quoted lines

> [...]
>> +++ b/builtin/clone.c
> [...]
>> @@ -848,16 +853,13 @@ int cmd_clone(int argc, const char **argv, const char *prefix)
>>       const struct ref *our_head_points_at;
>>       struct ref *mapped_refs;
>>       const struct ref *ref;
>> -     struct strbuf key = STRBUF_INIT, value = STRBUF_INIT;
>> +     struct strbuf key = STRBUF_INIT, default_refspec = STRBUF_INIT;
>
> nit: since it's not part of a key, value pair like value,
> default_refspec should probably go on its own line.

Fun fact: they were never part of a key-value pair. While 'key' is indeed the name of a configuration variable, 'value' is not the value of that configuration variable, or any other configuration variable for that matter.

Best, Gábor