Re: [PATCH 0/3] Supplements to "packed_ref_cache: don't use mmap() for small files"

Michael Haggerty [off-list ref] writes:

So I will follow up this email with three patches:

1. Mention that `snapshot::buf` can be NULL for empty files

   I suggest squashing this into your patch, to make it clear that
   `snapshot::buf` and `snapshot::eof` can also be NULL if the
   `packed-refs` file is empty.

2. create_snapshot(): exit early if the file was empty

   Avoid undefined behavior by returning early if `snapshot->buf` is
   NULL.

3. find_reference_location(): don't invoke if `snapshot->buf` is NULL

   Avoid undefined behavior and confusing semantics by not calling
   `find_reference_location()` when `snapshot->buf` is NULL.

These look all sensible with today's code and with v2 from this
thread.

With the v3, i.e. "do the xmalloc() even for size==0", however,
snapshot->buf would never be NULL, so I'd shelve them for now,
though.

Thanks.