Re: [PATCH 01/11] config-batch: basic boilerplate of new builtin

[Derrick Stolee <stolee@gmail.com>]

On 2/4/2026 6:23 PM, Junio C Hamano wrote:
> "Derrick Stolee via GitGitGadget" <gitgitgadget@gmail.com> writes:
> 
>> From: Derrick Stolee <stolee@gmail.com>
>>
>> Later changes will document, implement, and test this new builtin. For now,
>> this serves as the latest example of the minimum boilerplate to introduce a
>> new builtin.
>>
>> Recently, we updated the comment in builtin.h about how to create a new
>> builtin, but failed to mention the required change to meson.build files for
>> some CI builds to pass. Fix that oversight.
>>
>> Signed-off-by: Derrick Stolee <stolee@gmail.com>
>> ---
> 
> We have had a bad reputation for having too many commands; would it
> be better to present it as a new mode of existing "git config"
> command at the end-user level, I wonder?

Interesting thought. I think we also have a bad reputation of commands
that are overloaded with too many purposes.

In this case, though, I do think that the modern 'git config <subcommand>'
model presents some clear boundaries for how the command should behave
with the 'batch' (or 'server') subcommand. Grouping all config-related
operations in the same builtin may be ideal. 

> Also after reading patches for a few early steps, I do not quite see
> "batch"-ness in this protocol; it is strictly "a single request is
> met with a single response".

The batch-ness is that multiple requests can eventually go to the same
process. The client could collect multiple commands in a batch and send
them all without processing the responses one-by-one. This is how it works
in the tests: a single input file is prepared and all responses are
scanned after-the-fact.

The back-and-forth mechanism is how the git-credential-manager tool would
use it, because it dynamically explores certain config keys. For example:
it checks the deepest possible URL for a specific key then peels away the
last segment of the URL to see if there is a directory-prefix match in a
key. (This is the main reason that there are so many requests in this
application.)

I believe this is similar to how 'git cat-file --batch' or 'git cat-file
--batch-check' work, which was my inspiration for this word. If we regret
those names, then I'm happy to move towards a better name.

Thanks,
-Stolee