Backport of handle FSM.Apply
errors in raftApply
into release/1.5.x
#16303
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Backport
This PR is auto-generated from #16287 to be assessed for backporting due to the inclusion of the label backport/1.5.x.
The below text is copied from the body of the original PR.
The signature of the
raftApply
function requires that the caller unwrap the first returned value (the response fromFSM.Apply
) to see if it's an error. This puts the burden on the caller to remember to check two different places for errors, and we've done so inconsistently.Update
raftApply
to do the unwrapping for us and return anyFSM.Apply
error as the error value. Similar work was done in Consul in hashicorp/consul#9991. This eliminates some boilerplate and surfaces a few minor bugs in the process:Note that although most of the
FSM.Apply
functions return only errors (which makes it tempting to remove the first return value entirely), there are few that returnbool
for some reason and Variables relies on the response value for proper CAS checking.