Add a generic resolveHash method to VersionStore

[adutra]

Required for #7268.

For context: the existing hashOnReference method has the down side of throwing ReferenceNotFound if the hash is not reachable from the given NamedRef – even if the hash exists. This makes supporting relative hashes across the board harder to implement and could introduce unwanted behavioral changes in existing endpoints.

[snazy]

Not yet sure I understand the reasoning here. But let's wait for the PR proposed for #7268. Other than that, we'd have two very similar methods then, does it make sense to keep the relativeLookups parameter for hashOnReference after this PR and and the one for #7268?

[adutra]

Not yet sure I understand the reasoning here. But let's wait for the PR proposed for #7268. Other than that, we'd have two very similar methods then, does it make sense to keep the relativeLookups parameter for hashOnReference after this PR and and the one for #7268?

Indeed the intent will become clear with #7268 I hope. And yes, we'd need both, since sometimes we need to resolve the hash AND check that it belongs to the given named ref, but some other times (DETACHED cases mostly), we only need to resolve the hash.

[adutra]

Closing this, you were right: it turns out hashOnReference is enough for all cases. Sorry for the noise.