operations: Use `ExpectedOldOid` in `UserUpdateSubmodule`
If the clients provide the ExpectedOldOid
in the request of UserUpdateSubmodule
, we need to use this as the ref's current OID for updating the reference.
This is directly fed to git-update-ref(1) where it'll exit with an error code if the current OID of the ref doesn't match the OID provided by us. This allows us to avoid any race conditions wherein the branch was updated concurrently by another process.
Closes #4407 (closed)
Edited by Karthik Nayak