chore: fix deadlock in dbfake and incorrect lock types #7218
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I manually went through every single dbfake function and ensured it has the correct lock type depending on whether it writes or only reads. There were a surprising amount of methods that had the wrong lock type (Lock when only reading, or RLock when writing (!!!)). This also manually fixes every method that acquires a RLock and then calls a method that also acquires it's own RLock to use noLock methods instead. You cannot rely on acquiring a RLock twice in the same goroutine as RWMutex prioritizes any waiting Lock calls. I tried writing a ruleguard rule for this but because of limitations in ruleguard it doesn't seem possible.
mafredri
approved these changes
Apr 20, 2023
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For context: this was caught due to TestWorkspaceApps timing out (running for 6+ minutes) and Dean discovering that it was due to locks in DB fake, further confirmed by this never happening in the psql test (non-fakedb).
I tried writing a ruleguard rule for this but because of limitations in ruleguard it doesn't seem possible.
I also gave this a try, to no avail.
And PR LGTM!
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I manually went through every single dbfake function and ensured it has the correct lock type depending on whether it writes or only reads. There were a surprising amount of methods that had the wrong lock type (Lock when only reading, or RLock when writing (!!!)).
This also manually fixes every method that acquires a RLock and then calls a method that also acquires it's own RLock to use noLock methods instead. You cannot rely on acquiring a RLock twice in the same goroutine as RWMutex prioritizes any waiting Lock calls.
I tried writing a ruleguard rule for this but because of limitations in ruleguard it doesn't seem possible.