On Tue, Feb 11, 2020 at 1:05 AM brian m. carlson
[off-list ref] wrote:

quoted

As this is within the library, the hash size should be injected
somewhere. I don't see huge problems here (the hash size could be part
of the 'struct write_options'), but until we have properly defined how
reftable will mark the on-disk files as SHA-256, it will only supports
SHA1. I intend to work set the file format in motion, once this SHA1
version is accepted into git-core.

It's not required to mark the on-disk files.  A repository's storage is
either entirely SHA-1 or entirely SHA-256, except for the translation
tables.  The entire marking of the repository is in the config file, and
everything in the .git directory is assumed to be in that format.

I disagree. I think it should be possible to determine if a file in
reftable format is well-formed or not. Since parsing requires knowing
the hash size, we have to encode it somewhere.

I've uploaded https://git.eclipse.org/r/c/157501/ that proposes a way
to encode the hash size. I  look forward to feedback.

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