ff07b9f · distributed-process

git.iko.soy/distributed-process

Protect callLocal from asynchronous exceptions during the clean up.

Interrupting the cleanup could cause the original exception to be ignored (i.e. the exception which caused the clean up to be executed). Ignoring the exception could be problematic. For instance, the exception can be meant to kill the thread. A later exception comming during the clean up could come from a wrapping call of System.Timeout.timeout, which would rather interrupt the computation but certainly not kill the thread.

commitff07b9f514c0b5a1dcdb00d8bd9a66266804d63c authorFacundo Domínguez <facundo.dominguez@tweag.io> dateFri 25 Sep 2015, 17:23 (11 years ago) parentc59ad49

1 file changed+13−4

compare with master

unifiedsplit

src/Control/Distributed/Process.hs+13−4

src/Control/Distributed/Process.hs+13−4

@@ -199,6 +199,7 @@ import Control.Distributed.Process.Internal.Types

199199 , WhereIsReply(..)

200200 , RegisterReply(..)

201201 , LocalProcess(processNode)

202+ , runLocalProcess

202203 , Message

203204 )

204205import Control.Distributed.Process.Serializable (Serializable)

@@ -316,7 +317,7 @@ import Control.Distributed.Process.Internal.Spawn

316317 , spawnSupervised

317318 , call

318319 )

319−import Control.Exception (SomeException, throw)

320+import Control.Exception (SomeException, throw, uninterruptibleMask_)

320321

321322-- INTERNAL NOTES

322323--

@@ -421,7 +422,15 @@ callLocal proc = mask $ \release -> do

421422 try (sendChan spInit () >> release proc) >>= liftIO . putMVar mv

422423 rs <- liftIO (takeMVar mv)

423424 `onException`

424− do receiveChan rpInit

425− kill child "exception in parent process"

426− liftIO (takeMVar mv)

425+ -- Exceptions need to be prevented from interrupting the clean up or

426+ -- the original exception which caused entering the handler could be

427+ -- forgotten. For instance, this could have a problematic effect

428+ -- when the original exception was meant to kill the thread and the

429+ -- second exception doesn't (like the exception thrown by

430+ -- 'System.Timeout.timeout').

431+ do lproc <- ask

432+ liftIO $ uninterruptibleMask_ $ runLocalProcess lproc $ do

433+ receiveChan rpInit

434+ kill child "exception in parent process"

435+ liftIO (takeMVar mv)

427436 either throw return rs