Re: [PATCH] read-cache: avoid sparse-index expansion for unborn HEAD

On Fri, Aug 7, 2026 at 12:17 PM Elijah Newren <[email protected]> wrote:
>
> This explains what, but not why. It feels like a pedagogical exercise
> with no actual utility.

You are right, I found this through the TODO comment and do not have a
concrete user bug report or use case driving it.

> Why would someone with an unborn HEAD be using a sparse index? [...]

I do not have a good answer to that. My thinking was simply that
removing the special-case fallback still has some value: it deletes a
long-standing TODO, unifies the unborn-branch path with the normal diff
path, and removes an ensure_full_index() call that future readers would
need to reason about.

> This seems to presume a single dirty file, otherwise wouldn't the
> printing look pretty odd?

I agree that "dirty=%s" looks wrong when multiple paths are
present. I can fix that in v2.

Thanks for the review.