Re: [PATCH 15/20] sparse-index: create extension for compatibility

On 2/25/2021 2:45 AM, Elijah Newren wrote:

On Tue, Feb 23, 2021 at 12:14 PM Derrick Stolee via GitGitGadget
[off-list ref] wrote:

quoted

From: Derrick Stolee <redacted>

Previously, we enabled the sparse index format only using
GIT_TEST_SPARSE_INDEX=1. This is not a feasible direction for users to
actually select this mode. Further, sparse directory entries are not
understood by the index formats as advertised.

We _could_ add a new index version that explicitly adds these
capabilities, but there are nuances to index formats 2, 3, and 4 that
are still valuable to select as options. For now, create a repo
extension, "extensions.sparseIndex", that specifies that the tool
reading this repository must understand sparse directory entries.

This commit is unchanged from the RFC series, but given your comments
in the design document about how you do intend to create an index
format v5 now, do you want to reference that here?

I'll insert detail about v5.
 

quoted

+extensions.sparseIndex::
+       When combined with `core.sparseCheckout=true` and
+       `core.sparseCheckoutCone=true`, the index may contain entries
+       corresponding to directories outside of the sparse-checkout
+       definition. Versions of Git that do not understand this extension
+       do not expect directory entries in the index.

I had a wording suggestion for this paragraph in the RFC series --
https://lore.kernel.org/git/CABPp-BFEJE82k4VgkR=Jf7V7sZxZzo2pHMfAGshhi9_vV6iK0w@mail.gmail.com/ (local).
Let me know if you just decided to leave it out so I don't bug you
about stuff you already considered.

I'll take your suggestion, thanks.

-Stolee