There is currently a race-condition when diffing, where we get the
object and then run a server-side dry-run patch and compare the two
results. If something changes the object on the server between the get
and the patch, the diff is going to show unrelated changes. We can now
specify the exact revisionversion that we want to patch, and that will
return a conflict, and we can retry multiple times to get a
non-conflicting diff. Eventually (after 3 times), we diff without
checking the version and throw a warning that the diff might be
partially wrong.
