fix: Buffer.addPending sets writeRequired #1015
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```scala require(pending.isEmpty, "Pending should be empty if write not required") ``` suggests that an invariant of `journal.Buffer` is that `writeRequired || pending.nonEmpty`. The `addPending` method, if called on a `Buffer` where `writeRequired` is `false` will break this invariant, which may cause subsequent adds to the buffer to throw, crashing the `TagWriter` and forcing an `ActorSystem` restart.
patriknw
reviewed
Mar 24, 2023
| @@ -107,7 +107,7 @@ private[akka] case class Buffer( | |||
| } | |||
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| final def addPending(write: AwaitingWrite): Buffer = { | |||
| copy(size = size + write.events.size, pending = pending :+ write) | |||
| copy(size = size + write.events.size, pending = pending :+ write, writeRequired = true) | |||
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Seems innocent and correct but difficult to see the full consequences. Tests are failing.
I looked at other places where we add to pending and then it's indeed writeRequired = true aside from rebuild. Maybe it's always set to true in rebuild also via the add but that is not immediately obvious.
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In the case of rebuild, it starts empty, then repeatedly adds, so anything in pending after the repeated adds came via add.
I haven't yet looked through the test failures to see what they should be.
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close-open to run ci again |
johanandren
approved these changes
Oct 25, 2023
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Two successful runs in CI. |
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require(pending.isEmpty, "Pending should be empty if write not required")suggests that an invariant of
journal.Bufferis thatwriteRequired || pending.nonEmpty. TheaddPendingmethod, if called on aBufferwherewriteRequiredisfalsewill break this invariant, which may cause subsequent adds to the buffer to throw, crashing theTagWriterand forcing anActorSystemrestart.