I don't think it's possible with regular service functioning, but it happens
during testing because of pointer reuse:
WARNING: DATA RACE
Read at 0x00c003a0e3f0 by goroutine 114:
github.com/nspcc-dev/neo-go/pkg/services/notary.(*Notary).verifyIncompleteWitnesses()
/home/runner/work/neo-go/neo-go/pkg/services/notary/notary.go:441 +0x1dc
github.com/nspcc-dev/neo-go/pkg/services/notary.(*Notary).OnNewRequest()
/home/runner/work/neo-go/neo-go/pkg/services/notary/notary.go:188 +0x205
github.com/nspcc-dev/neo-go/pkg/core.TestNotary.func11()
/home/runner/work/neo-go/neo-go/pkg/core/notary_test.go:347 +0x612
github.com/nspcc-dev/neo-go/pkg/core.TestNotary()
/home/runner/work/neo-go/neo-go/pkg/core/notary_test.go:443 +0xe33
testing.tRunner()
/opt/hostedtoolcache/go/1.16.10/x64/src/testing/testing.go:1193 +0x202
Previous write at 0x00c003a0e3f0 by goroutine 104:
github.com/nspcc-dev/neo-go/pkg/services/notary.(*Notary).finalize()
/home/runner/work/neo-go/neo-go/pkg/services/notary/notary.go:338 +0x50a
github.com/nspcc-dev/neo-go/pkg/services/notary.(*Notary).PostPersist()
/home/runner/work/neo-go/neo-go/pkg/services/notary/notary.go:314 +0x297
github.com/nspcc-dev/neo-go/pkg/services/notary.(*Notary).Run()
/home/runner/work/neo-go/neo-go/pkg/services/notary/notary.go:169 +0x4a7
Serializing/deserializing the payload yields this:
Error: Received unexpected error:
both main and fallback transactions should have the same ValidUntil value
Notes for witnesses:
* [N sig + M multisig + K contract] combination is possible where N, M, K >=0.
* Each verification script should be properly filled in.
* Each invocation script should either be empty or contain exactly one
signature.
There was a deadlock while trying to finalize transaction during
PostBlock:
1) (*Notary).PostBlock is called under the blockchain lock
2) (*Notary).onTransaction is called inside the PostBlock
3) (*Notary).onTransaction needs to RLock the blockchain to add
completed transaction to the memory pool (and the blockchain is Lock'ed
by this moment)
The problem is fixed by using notifications subsistem, because it's not
required to call (*Notary).PostBlock under the blockchain lock.
