Re: [PATCH 03/23] midx: add midx builtin

[Derrick Stolee <stolee@gmail.com>]

On 6/11/2018 5:02 PM, Stefan Beller wrote:
> Hi Derrick,
> On Thu, Jun 7, 2018 at 7:03 AM Derrick Stolee <stolee@gmail.com> wrote:
>> This new 'git midx' builtin will be the plumbing access for writing,
>> reading, and checking multi-pack-index (MIDX) files. The initial
>> implementation is a no-op.
> Let's talk about the name for a second:
>
> .idx files are written by git-index-pack or as part of
> git-pack-objects (which just calls write_idx_file as part
> of finish_tmp_packfile), and the name actually suggests
> it writes the index files. I have a hard time understanding
> what the git-midx command does[1].
>
> With both commit graph as well as multi index we introduce
> a command that is centered around that concept (similar to
> git-remote or git-config that are centered around a concept,
> that is closely resembled by a file), but for indexes for packs
> it was integrated differently into Git. So I am not sure if I want
> to suggest to integrate it into the packfile commands as that
> doesn't really fit. But maybe we can have a name that is human
> readable instead of the file suffix? Maybe
>
>    git multi-pack-index ?
>
> I suppose that eventually this command is not really used by
> users as it will be used by other porcelain commands in the
> background or even as part of repack/gc so I am not worried
> about a long name, but I'd be more worried about understandability.

I'll use "git multi-pack-index" in v2. I'll keep "midx.c" in the root, 
though, if that is OK.

> [1] While these names are not perfect for the layman, it is okay?
>    I am sure you are aware of https://git-man-page-generator.lokaltog.net/

I was not, and enjoyed that quite a bit.

Thanks,
-Stolee

>
>
>> new file mode 100644
>> index 0000000000..2bd886f1a2
>> --- /dev/null
>> +++ b/Documentation/git-midx.txt
>> @@ -0,0 +1,29 @@
>> +git-midx(1)
>> +============
>> +
>> +NAME
>> +----
>> +git-midx - Write and verify multi-pack-indexes (MIDX files).
> The reading is done as part of all other commands.

I like to think the 'read' verb is a subset of "verify" because we are 
checking for information about the MIDX, and mostly for tests or debugging.

>
>> +
>> +
>> +SYNOPSIS
>> +--------
>> +[verse]
>> +'git midx' [--object-dir <dir>]
>> +
>> +DESCRIPTION
>> +-----------
>> +Write or verify a MIDX file.
>> +
>> +OPTIONS
>> +-------
>> +
>> +--object-dir <dir>::
>> +       Use given directory for the location of Git objects. We check
>> +       <dir>/packs/multi-pack-index for the current MIDX file, and
>> +       <dir>/packs for the pack-files to index.
>> +
>> +
> Maybe we could have a SEE ALSO section that points at
> the explanation of multi index files?
> (c.f. man git-submodule that has a  SEE ALSO
> gitsubmodules(7), gitmodules(5) explaining concepts(7)
> and the file(5))
>
> But as this is plumbing and users should not need to worry about it
> this is optional, I would think.

The design document is also in 'Documentation/technical' instead of just 
'Documentation/'. Do we have a pattern of linking to the technical 
documents?

Thanks,
-Stolee