Re: [PATCH v3 0/5] Sparse index: fetch, pull, ls-files

>
> This is based on ld/sparse-index-blame (merged with 'master' due to an
> unrelated build issue).
>
> Here are two relatively-simple patches that further the sparse index
> integrations.
>
> Did you know that 'fetch' and 'pull' read the index? I didn't, or this would
> have been an integration much earlier in the cycle. They read the index to
> look for the .gitmodules file in case there are submodules that need to be
> fetched. Since looking for a file by name is already protected, we only need
> to disable 'command_requires_full_index' and we are done.
>
> The 'ls-files' builtin is useful when debugging the index, and some scripts
> use it, too. We are not changing the default behavior which expands a sparse
> index in order to show all of the cached blobs. Instead, we add a '--sparse'
> option that allows us to see the sparse directory entries upon request.
> Combined with --debug, we can see a lot of index details, such as:
>
> $ git ls-files --debug --sparse
> LICENSE
>   ctime: 1634910503:287405820
>   mtime: 1634910503:287405820
>   dev: 16777220 ino: 119325319
>   uid: 501  gid: 20
>   size: 1098    flags: 200000
> README.md
>   ctime: 1634910503:288090279
>   mtime: 1634910503:288090279
>   dev: 16777220 ino: 119325320
>   uid: 501  gid: 20
>   size: 934 flags: 200000
> bin/index.js
>   ctime: 1634910767:828434033
>   mtime: 1634910767:828434033
>   dev: 16777220 ino: 119325520
>   uid: 501  gid: 20
>   size: 7292    flags: 200000
> examples/
>   ctime: 0:0
>   mtime: 0:0
>   dev: 0    ino: 0
>   uid: 0    gid: 0
>   size: 0   flags: 40004000
> package.json
>   ctime: 1634910503:288676330
>   mtime: 1634910503:288676330
>   dev: 16777220 ino: 119325321
>   uid: 501  gid: 20
>   size: 680 flags: 200000
>
>
> (In this example, the 'examples/' directory is sparse.)
>
> Thanks!
>
>
> Updates in v2
> =============
>
>  * Rebased onto latest ld/sparse-index-blame without issue.
>  * Updated the test to use diff-of-diffs instead of a sequence of greps.
>  * Added patches that remove the use of 'test-tool read-cache --table' and
>    its implementation.
>
>
> Updates in v3
> =============
>
>  * Fixed typo in commit message.
>  * Added comments around doing strange things in an ls-files test.
>  * Fixed adjacent typo in a test comment.