From: Derrick Stolee <derrickstolee@github.com>
Date: Wed, 09 Mar 2022 18:55:57 GMT
Subject: Re: [PATCH v4 09/13] bundle: parse filter capability
Message-ID: <858ccf36-3515-eeb6-2ad8-4a141d38d0c6@github.com>
In-Reply-To: <xmqqwnh3klyv.fsf@gitster.g>

On 3/9/2022 1:41 PM, Junio C Hamano wrote:
> "Derrick Stolee via GitGitGadget" <gitgitgadget@gmail.com> writes:
> 
>> diff --git a/Documentation/git-bundle.txt b/Documentation/git-bundle.txt
>> index 72ab8139052..ac4c4352aae 100644
>> --- a/Documentation/git-bundle.txt
>> +++ b/Documentation/git-bundle.txt
>> @@ -75,8 +75,11 @@ verify <file>::
>>  	cleanly to the current repository.  This includes checks on the
>>  	bundle format itself as well as checking that the prerequisite
>>  	commits exist and are fully linked in the current repository.
>> -	'git bundle' prints a list of missing commits, if any, and exits
>> -	with a non-zero status.
>> +	Information about additional capabilities, such as "object filter",
>> +	is printed. See "Capabilities" in link:technical/bundle-format.html
>> +	for more information. Finally, 'git bundle' prints a list of
>> +	missing commits, if any. The exit code is zero for success, but
>> +	will be nonzero if the bundle file is invalid.
> 
> Hmph.  I wasn't expecting this change (not objecting, but mostly am
> surprised) relative to the previous round where the filter was
> mentioned only when we issue an error message.  I was expecting to
> see something like "list-filters <file>", which is analog to the
> "list-heads <file>", to help those who want to programatically build
> around the "git bundle" command output.  Or "--list-capabilities" to
> accomodate the current, this, and future capabilities.  We already
> have the object-format thing before this series.  Do we have an
> interface to expose that out of a given bundle file?
 
The object format does _not_ appear to be output by 'git bundle verify'.
I just ran t6020 under GIT_TEST_DEFAULT_HASH=sha256 and see the
capability being written, but not output by verify:


The bundle contains these 10 refs:
d519553fbcf280df4448d588c25a51872f2d8dec95ba65a8a1bd3c64a5eec664 refs/heads/main
265b1effb3fdb80e04f7ea64e717f5677ddf57d00145dce7c508ba1f5ddb9081 refs/heads/release
611ac8182ea26d7aad227873b70f584593af1aa584bbdd37b36055e71be6ccd7 refs/heads/topic/1
4251af01ec70cdca692a3d15d78ccb9a6ca92ef344bd2dbc3bac20081347ae9b refs/heads/topic/2
611ac8182ea26d7aad227873b70f584593af1aa584bbdd37b36055e71be6ccd7 refs/pull/1/head
ec7e40a591df46923b25fd44bd86a2a80927f343d141f55ddf295c5d2d57959e refs/pull/2/head
754e9363bbfce179d35ccc48ae3a3c81db95a489cc632fafe5c10b25aed29d74 refs/tags/v1
a96c78650835f2041c49dce964bb759add14cfc4d35af3b7ee2b22289f9ba817 refs/tags/v2
398a930e72d21ea455c982227cca3c8fb5feb88c31f1d42226a3e6c42ff8db8f refs/tags/v3
d519553fbcf280df4448d588c25a51872f2d8dec95ba65a8a1bd3c64a5eec664 HEAD
The bundle uses this filter: blob:none
The bundle records a complete history.
partial.bdl is okay


This output does not seem to be designed for machine parsing, so
this extension of "The bundle uses this filter:" shouldn't be
problematic. A similar addition for object-format should be
possible as a follow-up.

Further, it seems you are asking for something that just reads
the header and supplies valuable data from the header such as
the refs and the capabilities. Perhaps 'git bundle header <file>'?

(We already have 'git bundle list-heads', so maybe we should
leave the refs out of 'git bundle header' output?)

I can add both as follow-ups to my existing list of things.

Thanks,
-Stolee