Subject: Re: [PATCH v2 2/4] bundle API: change "flags" to be "extra_index_pack_args"

From: Ævar Arnfjörð Bjarmason <[email-masked]>
Date: Tue, 24 Aug 2021 23:41:22 +0200

On Tue, Aug 24 2021, Derrick Stolee wrote:

> On 8/23/2021 7:02 AM, Ævar Arnfjörð Bjarmason wrote:
> ...
>> --- a/builtin/bundle.c
>> +++ b/builtin/bundle.c
>> @@ -165,7 +165,8 @@ static int cmd_bundle_unbundle(int argc, const char **argv, const char *prefix)
>>  	struct option options[] = {
>>  		OPT_END()
>>  	};
>> -	char *bundle_file;
>> +	char* bundle_file;
>
> nit: errant movement of "*" here.

Ah, thanks.

>> +	struct strvec extra_args = STRVEC_INIT;
> ...
>> -	ret = !!unbundle(the_repository, &header, bundle_fd, 0) ||
>> +	ret = !!unbundle(the_repository, &header, bundle_fd, &extra_args) ||
>
> I'm assuming that you will be adding something that adds to extra_args
> in a future commit. It might be better to just convert the "0" to "NULL"
> here and add extra_args when you actually use it.

*nod*, commented on in the later commit.

>>  int unbundle(struct repository *r, struct bundle_header *header,
>> -	     int bundle_fd, int flags)
>> +	     int bundle_fd, struct strvec *extra_index_pack_args)
>>  {
>> -	const char *argv_index_pack[] = {"index-pack",
>> -					 "--fix-thin", "--stdin", NULL, NULL};
>>  	struct child_process ip = CHILD_PROCESS_INIT;
>> +	int i;
>>  
>> -	if (flags & BUNDLE_VERBOSE)
>> -		argv_index_pack[3] = "-v";
>> +	strvec_push(&ip.args, "index-pack");
>> +	strvec_push(&ip.args, "--fix-thin");
>> +	strvec_push(&ip.args, "--stdin");
>> +	if (extra_index_pack_args) {
>> +		struct strvec *extra = extra_index_pack_args;
>
> Creating a shorter variable name seems unnecessary.

Will skip it.

>> +		for (i = 0; i < extra->nr; i++)
>> +			strvec_push(&ip.args, extra->v[i]);
>
> This seems like a good opportunity to create and use a
> strvec_concat() method.

Yeah, I guess I could start with that. Will try it.

>> +		strvec_clear(extra_index_pack_args);
>
> Why is it the responsibility of this method to clear these args?
> I suppose it is convenient. It just seems a bit wrong to me.

Because of...

>>  /**
>>   * Unbundle after reading the header with read_bundle_header().
>>   *
>>   * We'll invoke "git index-pack --stdin --fix-thin" for you on the
>>   * provided `bundle_fd` from read_bundle_header().
>> + *
>> + * Provide extra_index_pack_args to pass any extra arguments
>> + * (e.g. "-v" for verbose/progress), NULL otherwise. The provided
>> + * extra_index_pack_args (if any) will be strvec_clear()'d for you
>> + * (like the run-command.h API itself does).

... this, i.e. it's how the run-command.[ch] API already works for the
same sort of thing elsewhere, I figured making them consistent was
better than having them differ.

I think that while in general the rule of having each function allocate
& clear its own memory is a good one, that a notable good exception in
our codebase is various "one-shot" functions such as the run-command
API, i.e. APIs where the vast majority of callers just want to set
things up for a one-off run. Having those common cases not require a
that_api_release(&ctx) afterwards seems like a good idea in general.

>>   */
>>  int unbundle(struct repository *r, struct bundle_header *header,
>> -	     int bundle_fd, int flags);
>> +	     int bundle_fd, struct strvec *extra_index_pack_args);
>>  int list_bundle_refs(struct bundle_header *header,
>>  		int argc, const char **argv);
>>  
>> diff --git a/transport.c b/transport.c
>> index 17e9629710a..8bc4b5fcd3c 100644
>> --- a/transport.c
>> +++ b/transport.c
>> @@ -162,12 +162,15 @@ static int fetch_refs_from_bundle(struct transport *transport,
>>  			       int nr_heads, struct ref **to_fetch)
>>  {
>>  	struct bundle_transport_data *data = transport->data;
>> +	struct strvec extra_index_pack_args = STRVEC_INIT;
>>  	int ret;
>>  
>> +	strvec_push(&extra_index_pack_args, "-v");
>> +
>>  	if (!data->get_refs_from_bundle_called)
>>  		get_refs_from_bundle(transport, 0, NULL);
>>  	ret = unbundle(the_repository, &data->header, data->fd,
>> -			   transport->progress ? BUNDLE_VERBOSE : 0);
>
> Previously, this was conditioned on 'transport->progress', but above
> you unconditionally add the "-v" option. Seems like a bug.

Yes! Oops. Will fix. Thanks.