{-# LANGUAGE BangPatterns #-} {-# LANGUAGE ExplicitNamespaces #-} {-# LANGUAGE LambdaCase #-} {-# LANGUAGE NamedFieldPuns #-} {-# LANGUAGE QuantifiedConstraints #-} {-# LANGUAGE RankNTypes #-} {-# LANGUAGE ScopedTypeVariables #-} {-# LANGUAGE TupleSections #-} {-# OPTIONS_GHC -Wno-name-shadowing #-} {-# OPTIONS_GHC -Wno-unrecognised-pragmas #-} module Control.Monad.IOSim ( -- * Simulation monad IOSim , STMSim -- ** Run simulation , runSim , runSimOrThrow , runSimStrictShutdown , Failure (..) , runSimTrace , runSimTraceST -- *** QuickCheck Monadic combinators , monadicIOSim_ , monadicIOSim , runIOSimGen -- ** Explore races using /IOSimPOR/ -- $iosimpor , exploreSimTrace , exploreSimTraceST , controlSimTrace , controlSimTraceST , ScheduleMod (..) , ScheduleControl (..) -- *** Exploration options , ExplorationSpec , ExplorationOptions (..) , stdExplorationOptions , withScheduleBound , withBranching , withStepTimelimit , withReplay -- * Lift ST computations , liftST -- * Simulation time , setCurrentTime , unshareClock -- * Simulation trace , type SimTrace , Trace (Cons, Nil, SimTrace, SimPORTrace, TraceDeadlock, TraceLoop, TraceMainReturn, TraceMainException, TraceRacesFound, TraceInternalError) , SimResult (..) , SimEvent (..) , SimEventType (..) , ThreadLabel , IOSimThreadId (..) , Labelled (..) -- ** Dynamic Tracing , traceM , traceSTM -- ** Pretty printers , ppTrace , ppTrace_ , ppEvents , ppSimEvent , ppDebug -- ** Selectors , traceEvents , traceResult -- *** list selectors , selectTraceEvents , selectTraceEvents' , selectTraceEventsDynamic , selectTraceEventsDynamicWithTime , selectTraceEventsDynamic' , selectTraceEventsDynamicWithTime' , selectTraceEventsSay , selectTraceEventsSayWithTime , selectTraceEventsSay' , selectTraceEventsSayWithTime' , selectTraceRaces -- *** trace selectors , traceSelectTraceEvents , traceSelectTraceEventsDynamic , traceSelectTraceEventsSay -- ** IO printer , printTraceEventsSay -- * Eventlog , EventlogEvent (..) , EventlogMarker (..) -- * Low-level API , Timeout , newTimeout , readTimeout , cancelTimeout , awaitTimeout ) where import Prelude import Data.Bifoldable import Data.Bifunctor (first) import Data.Dynamic (fromDynamic) import Data.Functor (void) import Data.List (intercalate) import Data.Maybe (catMaybes) import Data.Set (Set) import Data.Set qualified as Set import Data.Typeable (Typeable) import Data.List.Trace (Trace (..)) import Data.List.Trace qualified as Trace import Control.Exception (throw) import Control.Monad.ST.Lazy import Data.STRef.Lazy import Control.Monad.Class.MonadThrow as MonadThrow import Control.Monad.IOSim.Internal (runSimTraceST) import Control.Monad.IOSim.Types import Control.Monad.IOSimPOR.Internal qualified as IOSimPOR (controlSimTraceST) import Control.Monad.IOSimPOR.QuickCheckUtils import Test.QuickCheck import Test.QuickCheck.Gen.Unsafe (Capture (..), capture) import Test.QuickCheck.Monadic (PropertyM, monadic') import Debug.Trace qualified as Debug import System.IO.Unsafe -- | Select events according to the predicate function. It throws an error if -- the simulation ends with 'Failure'. -- selectTraceEvents :: (Time -> SimEventType -> Maybe b) -> SimTrace a -> [b] selectTraceEvents fn = bifoldr ( \ v _ -> case v of MainException _ _ e _ -> throw (FailureException e) Deadlock _ threads -> throw (FailureDeadlock threads) MainReturn _ _ _ _ -> [] Loop -> error "Impossible: selectTraceEvents _ TraceLoop{}" InternalError msg -> throw (FailureInternal msg) ) ( \ b acc -> b : acc ) [] . traceSelectTraceEvents fn -- | Like 'selectTraceEvents', but it returns even if the simulation trace ends -- with 'Failure'. -- selectTraceEvents' :: (Time -> SimEventType -> Maybe b) -> SimTrace a -> [b] selectTraceEvents' fn = bifoldr ( \ _ _ -> [] ) ( \ b acc -> b : acc ) [] . traceSelectTraceEvents fn selectTraceRaces :: SimTrace a -> [ScheduleControl] selectTraceRaces = go where go (SimTrace _ _ _ _ trace) = go trace go (SimPORTrace _ _ _ _ _ trace) = go trace go (TraceRacesFound races trace) = races ++ go trace go _ = [] -- Extracting races from a trace. There is a subtlety in doing so: we -- must return a defined list of races even in the case where the -- trace is infinite, and there are no races occurring in it! For -- example, if the system falls into a deterministic infinite loop, -- then there will be no races to find. -- In reality we only want to extract races from *the part of the -- trace used in a test*. We can only observe that by tracking lazy -- evaluation: only races that were found in the evaluated prefix of -- an infinite trace should contribute to the "races found". Hence we -- return a function that returns the races found "so far". This is -- unsafe, of course, since that function may return different results -- at different times. -- | Detach discovered races. This is written in `ST` monad to support -- simulations which do not terminate, in which case we will only detach races -- up to the point we evaluated the simulation. -- detachTraceRacesST :: forall a s. SimTrace a -> ST s (ST s [ScheduleControl], SimTrace a) detachTraceRacesST trace0 = do races <- newSTRef [] let readRaces :: ST s [ScheduleControl] readRaces = concat . reverse <$> readSTRef races saveRaces :: [ScheduleControl] -> ST s () saveRaces rs = modifySTRef races (rs:) go :: SimTrace a -> ST s (SimTrace a) go (SimTrace a b c d trace) = SimTrace a b c d <$> go trace go (SimPORTrace _ _ _ _ EventRaces {} trace) = go trace go (SimPORTrace a b c d e trace) = SimPORTrace a b c d e <$> go trace go (TraceRacesFound rs trace) = saveRaces rs >> go trace go t = return t trace <- go trace0 return (readRaces, trace) -- | Like `detachTraceRacesST`, but it doesn't expose discovered races. -- detachTraceRaces :: forall a. SimTrace a -> SimTrace a detachTraceRaces = Trace.filter (\a -> case a of SimPOREvent { seType = EventRaces {} } -> False SimRacesFound {} -> False _ -> True) -- | Select all the traced values matching the expected type. It relies on the -- sim's dynamic trace facility. -- -- For convenience, it throws exceptions for abnormal sim termination. -- selectTraceEventsDynamic :: forall a b. Typeable b => SimTrace a -> [b] selectTraceEventsDynamic = selectTraceEvents fn where fn :: Time -> SimEventType -> Maybe b fn _ (EventLog dyn) = fromDynamic dyn fn _ _ = Nothing -- | Like 'selectTraceEventsDynamic' but it also captures time of the trace -- event. -- selectTraceEventsDynamicWithTime :: forall a b. Typeable b => SimTrace a -> [(Time, b)] selectTraceEventsDynamicWithTime = selectTraceEvents fn where fn :: Time -> SimEventType -> Maybe (Time, b) fn t (EventLog dyn) = (t,) <$> fromDynamic dyn fn _ _ = Nothing -- | Like 'selectTraceEventsDynamic' but it returns even if the simulation trace -- ends with 'Failure'. -- selectTraceEventsDynamic' :: forall a b. Typeable b => SimTrace a -> [b] selectTraceEventsDynamic' = selectTraceEvents' fn where fn :: Time -> SimEventType -> Maybe b fn _ (EventLog dyn) = fromDynamic dyn fn _ _ = Nothing -- | Like `selectTraceEventsDynamic'` but it also captures time of the trace -- event. -- selectTraceEventsDynamicWithTime' :: forall a b. Typeable b => SimTrace a -> [(Time, b)] selectTraceEventsDynamicWithTime' = selectTraceEvents' fn where fn :: Time -> SimEventType -> Maybe (Time, b) fn t (EventLog dyn) = (t,) <$> fromDynamic dyn fn _ _ = Nothing -- | Get a trace of 'EventSay'. -- -- For convenience, it throws exceptions for abnormal sim termination. -- selectTraceEventsSay :: SimTrace a -> [String] selectTraceEventsSay = selectTraceEvents fn where fn :: Time -> SimEventType -> Maybe String fn _ (EventSay s) = Just s fn _ _ = Nothing -- | Like 'selectTraceEventsSay' but it also captures time of the trace event. -- selectTraceEventsSayWithTime :: SimTrace a -> [(Time, String)] selectTraceEventsSayWithTime = selectTraceEvents fn where fn :: Time -> SimEventType -> Maybe (Time, String) fn t (EventSay s) = Just (t, s) fn _ _ = Nothing -- | Like 'selectTraceEventsSay' but it returns even if the simulation trace -- ends with 'Failure'. -- selectTraceEventsSay' :: SimTrace a -> [String] selectTraceEventsSay' = selectTraceEvents' fn where fn :: Time -> SimEventType -> Maybe String fn _ (EventSay s) = Just s fn _ _ = Nothing -- | Like `selectTraceEventsSay'` but it also captures time of the trace event. -- selectTraceEventsSayWithTime' :: SimTrace a -> [(Time, String)] selectTraceEventsSayWithTime' = selectTraceEvents' fn where fn :: Time -> SimEventType -> Maybe (Time, String) fn t (EventSay s) = Just (t, s) fn _ _ = Nothing -- | Print all 'EventSay' to the console. -- -- For convenience, it throws exceptions for abnormal sim termination. -- printTraceEventsSay :: SimTrace a -> IO () printTraceEventsSay = mapM_ print . selectTraceEventsSay -- | The most general select function. It is a /total function/. -- traceSelectTraceEvents :: (Time -> SimEventType -> Maybe b) -> SimTrace a -> Trace (SimResult a) b traceSelectTraceEvents fn = bifoldr ( \ v _acc -> Nil v ) ( \ eventCtx acc -> case eventCtx of SimRacesFound _ -> acc SimEvent{} -> case fn (seTime eventCtx) (seType eventCtx) of Nothing -> acc Just b -> Cons b acc SimPOREvent{} -> case fn (seTime eventCtx) (seType eventCtx) of Nothing -> acc Just b -> Cons b acc ) undefined -- it is ignored -- | Select dynamic events. It is a /total function/. -- traceSelectTraceEventsDynamic :: forall a b. Typeable b => SimTrace a -> Trace (SimResult a) b traceSelectTraceEventsDynamic = traceSelectTraceEvents fn where fn :: Time -> SimEventType -> Maybe b fn _ (EventLog dyn) = fromDynamic dyn fn _ _ = Nothing -- | Select say events. It is a /total function/. -- traceSelectTraceEventsSay :: forall a. SimTrace a -> Trace (SimResult a) String traceSelectTraceEventsSay = traceSelectTraceEvents fn where fn :: Time -> SimEventType -> Maybe String fn _ (EventSay s) = Just s fn _ _ = Nothing -- | Simulation terminated a failure. -- data Failure = -- | The main thread terminated with an exception. FailureException SomeException -- | The threads all deadlocked. | FailureDeadlock ![Labelled IOSimThreadId] -- | The main thread terminated normally but other threads were still -- alive, and strict shutdown checking was requested. -- See 'runSimStrictShutdown'. | FailureSloppyShutdown [Labelled IOSimThreadId] -- | An exception was thrown while evaluation the trace. -- This could be an internal assertion failure of `io-sim` or an -- unhandled exception in the simulation. | FailureEvaluation SomeException -- | An internal failure of the simulator. -- -- Please open an issue at -- . | FailureInternal String deriving Show instance Exception Failure where displayException (FailureException err) = displayException err displayException (FailureDeadlock threads) = concat [ "<>" ] displayException (FailureSloppyShutdown threads) = concat [ "<>" ] displayException (FailureEvaluation err) = concat [ "<>" ] displayException (FailureInternal msg) = concat [ "<>\n" , "please report the issue at\n" , "https://github.com/input-output-hk/io-sim/issues" ] -- | 'IOSim' is a pure monad. -- runSim :: forall a. (forall s. IOSim s a) -> Either Failure a runSim mainAction = traceResult False (runSimTrace mainAction) -- | For quick experiments and tests it is often appropriate and convenient to -- simply throw failures as exceptions. -- runSimOrThrow :: forall a. (forall s. IOSim s a) -> a runSimOrThrow mainAction = case runSim mainAction of Left e -> throw e Right x -> x -- | Like 'runSim' but fail when the main thread terminates if there are other -- threads still running or blocked. If one is trying to follow a strict thread -- clean-up policy then this helps testing for that. -- runSimStrictShutdown :: forall a. (forall s. IOSim s a) -> Either Failure a runSimStrictShutdown mainAction = traceResult True (runSimTrace mainAction) -- | Fold through the trace and return either 'Failure' or a simulation -- result, i.e. the return value of the main thread. -- traceResult :: Bool -- ^ if True the simulation will fail if there are any threads which -- didn't terminated when the main thread terminated. -> SimTrace a -- ^ simulation trace -> Either Failure a traceResult strict = unsafePerformIO . eval where eval :: SimTrace a -> IO (Either Failure a) eval a = do r <- try (evaluate a) case r of Left e -> return (Left (FailureEvaluation e)) Right _ -> go a go :: SimTrace a -> IO (Either Failure a) go (SimTrace _ _ _ _ t) = eval t go (SimPORTrace _ _ _ _ _ t) = eval t go (TraceRacesFound _ t) = eval t go (TraceMainReturn _ _ _ tids@(_:_)) | strict = pure $ Left (FailureSloppyShutdown tids) go (TraceMainReturn _ _ x _) = pure $ Right x go (TraceMainException _ _ e _) = pure $ Left (FailureException e) go (TraceDeadlock _ threads) = pure $ Left (FailureDeadlock threads) go TraceLoop{} = error "Impossible: traceResult TraceLoop{}" go (TraceInternalError msg) = pure $ Left (FailureInternal msg) -- | Turn 'SimTrace' into a list of timestamped events. -- traceEvents :: SimTrace a -> [(Time, IOSimThreadId, Maybe ThreadLabel, SimEventType)] traceEvents (SimTrace time tid tlbl event t) = (time, tid, tlbl, event) : traceEvents t traceEvents (SimPORTrace time tid _ tlbl event t) = (time, tid, tlbl, event) : traceEvents t traceEvents _ = [] -- | Pretty print a timestamped event. -- ppEvents :: [(Time, IOSimThreadId, Maybe ThreadLabel, SimEventType)] -> String ppEvents events = intercalate "\n" [ ppSimEvent timeWidth tidWidth width SimEvent {seTime, seThreadId, seThreadLabel, seType } | (seTime, seThreadId, seThreadLabel, seType) <- events ] where timeWidth = maximum [ length (show t) | (t, _, _, _) <- events ] tidWidth = maximum [ length (show tid) | (_, tid, _, _) <- events ] width = maximum [ maybe 0 length threadLabel | (_, _, threadLabel, _) <- events ] -- | See 'runSimTraceST' below. -- runSimTrace :: forall a. (forall s. IOSim s a) -> SimTrace a runSimTrace mainAction = runST (runSimTraceST mainAction) -- -- IOSimPOR -- -- -- $iosimpor -- -- /IOSimPOR/ is a different interpreter of 'IOSim' which has the ability to -- discover race conditions and replay the simulation using a schedule which -- reverts them. For extended documentation how to use it see -- [here](https://github.com/input-output-hk/io-sim/blob/main/io-sim/how-to-use-IOSimPOR.md). -- -- /IOSimPOR/ only discovers races between events which happen in the same time -- slot. In /IOSim/ and /IOSimPOR/ time only moves explicitly through timer -- events, e.g. things like `Control.Monad.Class.MonadTimer.SI.threadDelay`, -- `Control.Monad.Class.MonadTimer.SI.registerDelay` or the -- `Control.Monad.Class.MonadTimer.MonadTimeout.NonStandard` API. The usual -- QuickCheck techniques can help explore different schedules of -- threads too. -- | Execute a simulation, discover & revert races. Note that this will execute -- the simulation multiple times with different schedules, and thus it's much -- more costly than a simple `runSimTrace` (also the simulation environments has -- much more state to track and hence it is slower). -- -- On property failure it will show the failing schedule (`ScheduleControl`) -- which can be passed to `controlSimTrace` to reproduce the failure without -- discovering the schedule. -- exploreSimTrace :: forall a test. Testable test => (ExplorationOptions -> ExplorationOptions) -- ^ modify default exploration options -> (forall s. IOSim s a) -- ^ a simulation to run -> (Maybe (SimTrace a) -> SimTrace a -> test) -- ^ a callback which receives the previous trace (e.g. before reverting -- a race condition) and current trace -> Property exploreSimTrace optsf main k = runST (exploreSimTraceST optsf main (\a b -> pure (k a b))) -- | An 'ST' version of 'exploreSimTrace'. The callback also receives -- 'ScheduleControl'. This is mostly useful for testing /IOSimPOR/ itself. -- exploreSimTraceST :: forall s a test. Testable test => (ExplorationOptions -> ExplorationOptions) -> (forall s. IOSim s a) -> (Maybe (SimTrace a) -> SimTrace a -> ST s test) -> ST s Property exploreSimTraceST optsf main k = case explorationReplay opts of Just control -> do trace <- controlSimTraceST (explorationStepTimelimit opts) control main counterexample ("Schedule control: " ++ show control) <$> k Nothing trace Nothing -> do cacheRef <- createCacheST prop <- go cacheRef (explorationScheduleBound opts) (explorationBranching opts) ControlDefault Nothing !size <- cacheSizeST cacheRef return $ tabulate "Modified schedules explored" [bucket size] prop where opts = optsf stdExplorationOptions go :: STRef s (Set ScheduleControl) -> Int -- schedule bound -> Int -- branching factor -> ScheduleControl -> Maybe (SimTrace a) -> ST s Property go cacheRef n m control passingTrace = do traceWithRaces <- IOSimPOR.controlSimTraceST (explorationStepTimelimit opts) control main (readRaces, trace0) <- detachTraceRacesST traceWithRaces (readSleeperST, trace) <- compareTracesST passingTrace trace0 () <- traceDebugLog (explorationDebugLevel opts) traceWithRaces conjoinNoCatchST [ do sleeper <- readSleeperST prop <- k passingTrace trace return $ counterexample ("Schedule control: " ++ show control) $ counterexample (case sleeper of Nothing -> "No thread delayed" Just ((t,tid,lab),racing) -> showThread (tid,lab) ++ " delayed at time "++ show t ++ "\n until after:\n" ++ unlines (map ((" "++).showThread) $ Set.toList racing) ) prop , do let limit = (n+m-1) `div` m -- To ensure the set of schedules explored is deterministic, we -- filter out cached ones *after* selecting the children of this -- node. races <- catMaybes <$> (readRaces >>= traverse (cachedST cacheRef) . take limit) let branching = length races -- tabulate "Races explored" (map show races) $ tabulate "Branching factor" [bucket branching] . tabulate "Race reversals per schedule" [bucket (raceReversals control)] . conjoin <$> sequence [ go cacheRef n' ((m-1) `max` 1) r (Just trace0) | (r,n') <- zip races (divide (n-branching) branching) ] ] bucket :: Int -> String bucket n | n<10 = show n | otherwise = buck n 1 buck n t | n<10 = show (n*t) ++ "-" ++ show ((n+1)*t-1) | otherwise = buck (n `div` 10) (t*10) -- divide n into k factors which sums up to n divide :: Int -> Int -> [Int] divide n k = [ n `div` k + if i < n `mod` k then 1 else 0 | i <- [0..k-1] ] showThread :: (IOSimThreadId,Maybe ThreadLabel) -> String showThread (tid,lab) = ppIOSimThreadId tid ++ (case lab of Nothing -> "" Just l -> " ("++l++")") -- insert a schedule into the cache cachedST :: STRef s (Set ScheduleControl) -> ScheduleControl -> ST s (Maybe ScheduleControl) cachedST cacheRef a = do set <- readSTRef cacheRef writeSTRef cacheRef (Set.insert a set) return $ if Set.member a set then Nothing else Just a -- -- Caching in ST monad -- -- It is possible for the same control to be generated several times. -- To avoid exploring them twice, we keep a cache of explored schedules. createCacheST :: ST s (STRef s (Set ScheduleControl)) createCacheST = newSTRef $ -- we use opts here just to be sure the reference cannot be -- lifted out of exploreSimTrace if explorationScheduleBound opts >=0 then Set.empty else error "exploreSimTrace: negative schedule bound" cacheSizeST :: STRef s (Set ScheduleControl) -> ST s Int cacheSizeST = fmap Set.size . readSTRef -- | Trace `SimTrace` to `stderr`. -- traceDebugLog :: Int -> SimTrace a -> ST s () traceDebugLog logLevel _trace | logLevel <= 0 = pure () traceDebugLog 1 trace = Debug.traceM $ "Simulation trace with discovered schedules:\n" ++ Trace.ppTrace (ppSimResult 0 0 0) (ppSimEvent 0 0 0) (ignoreRaces $ void `first` trace) traceDebugLog _ trace = Debug.traceM $ "Simulation trace with discovered schedules:\n" ++ Trace.ppTrace (ppSimResult 0 0 0) (ppSimEvent 0 0 0) (void `first` trace) -- | Run a simulation using a given schedule. This is useful to reproduce -- failing cases without exploring the races. -- controlSimTrace :: forall a. Maybe Int -- ^ limit on the computation time allowed per scheduling step, for -- catching infinite loops etc. -> ScheduleControl -- ^ a schedule to replay -- -- /note/: must be either `ControlDefault` or `ControlAwait`. -> (forall s. IOSim s a) -- ^ a simulation to run -> SimTrace a controlSimTrace limit control main = runST (controlSimTraceST limit control main) controlSimTraceST :: Maybe Int -> ScheduleControl -> IOSim s a -> ST s (SimTrace a) controlSimTraceST limit control main = detachTraceRaces <$> IOSimPOR.controlSimTraceST limit control main -- -- Utils -- ignoreRaces :: SimTrace a -> SimTrace a ignoreRaces = Trace.filter (\a -> case a of SimPOREvent { seType = EventRaces {} } -> False _ -> True) raceReversals :: ScheduleControl -> Int raceReversals ControlDefault = 0 raceReversals (ControlAwait mods) = length mods raceReversals ControlFollow{} = error "Impossible: raceReversals ControlFollow{}" -- `compareTracesST` is given (maybe) a passing trace and a failing trace, -- and identifies the point at which they diverge, where it inserts a -- "sleep" event for the thread that is delayed in the failing case, -- and a "wake" event before its next action. It also returns the -- identity and time of the sleeping thread. Since we expect the trace -- to be consumed lazily (and perhaps only partially), and since the -- sleeping thread is not of interest unless the trace is consumed -- this far, then we collect its identity only if it is reached using -- `unsafePerformIO`. -- TODO: return StepId compareTracesST :: forall a b s. Maybe (SimTrace a) -- ^ passing -> SimTrace b -- ^ failing -> ST s ( ST s (Maybe ( (Time, IOSimThreadId, Maybe ThreadLabel) , Set.Set (IOSimThreadId, Maybe ThreadLabel) )) , SimTrace b ) compareTracesST Nothing trace = return (return Nothing, trace) compareTracesST (Just passing) trace = do sleeper <- newSTRef Nothing trace' <- go sleeper passing trace return ( readSTRef sleeper , trace' ) where go :: STRef s (Maybe ( (Time, IOSimThreadId, Maybe ThreadLabel) , Set.Set (IOSimThreadId, Maybe ThreadLabel) )) -> SimTrace a -- ^ passing -> SimTrace b -- ^ failing -> ST s (SimTrace b) go sleeper (SimPORTrace tpass tidpass _ _ _ pass') (SimPORTrace tfail tidfail tstepfail tlfail evfail fail') | (tpass,tidpass) == (tfail,tidfail) = SimPORTrace tfail tidfail tstepfail tlfail evfail <$> go sleeper pass' fail' go sleeper (SimPORTrace tpass tidpass tsteppass tlpass _ _) fail = do writeSTRef sleeper $ Just ((tpass, tidpass, tlpass),Set.empty) SimPORTrace tpass tidpass tsteppass tlpass EventThreadSleep <$> wakeup sleeper tidpass fail go _ SimTrace {} _ = error "compareTracesST: invariant violation" go _ _ SimTrace {} = error "compareTracesST: invariant violation" go _ _ fail = return fail wakeup :: STRef s (Maybe ( (Time, IOSimThreadId, Maybe ThreadLabel) , Set.Set (IOSimThreadId, Maybe ThreadLabel) )) -> IOSimThreadId -> SimTrace b -> ST s (SimTrace b) wakeup sleeper tidpass fail@(SimPORTrace tfail tidfail tstepfail tlfail evfail fail') | tidpass == tidfail = return $ SimPORTrace tfail tidfail tstepfail tlfail EventThreadWake fail | otherwise = do ms <- readSTRef sleeper case ms of Just (slp, racing) -> do writeSTRef sleeper $ Just (slp,Set.insert (tidfail,tlfail) racing) SimPORTrace tfail tidfail tstepfail tlfail evfail <$> wakeup sleeper tidpass fail' Nothing -> error "compareTraceST: invariant violation" wakeup _ _ SimTrace {} = error "compareTracesST: invariant violation" wakeup _ _ fail = return fail -- -- QuickCheck monadic combinators -- -- | Like . -- -- Note: it calls `traceResult` in non-strict mode, e.g. leaked threads do not -- cause failures. -- -- @since 1.4.1.0 -- monadicIOSim_ :: Testable a => (forall s. PropertyM (IOSim s) a) -> Property monadicIOSim_ sim = monadicIOSim (\e -> case traceResult False e of Left e -> counterexample (show e) False Right p -> p) id sim -- | A more general version of `monadicIOSim_`, which: -- -- * allows to run in monad stacks build on top of `IOSim`; -- * gives more control how to attach debugging information to failed -- tests. -- -- Note, to use this combinator your monad needs to be defined as: -- -- > newtype M s a = M s { runM :: ReaderT State (IOSim s) a } -- -- It's important that `M s` is a monad. For such a monad one you'll need provide -- a natural transformation: -- @ -- -- the state could also be created as an `IOSim` computation. -- nat :: forall s a. State -> M s a -> 'IOSim' s a -- nat state m = runStateT (runM m) state -- @ -- -- @since 1.4.1.0 -- monadicIOSim :: (Testable a, forall s. Monad (m s)) => (SimTrace Property -> Property) -- ^ Allows to trace `SimTrace` in counterexamples. The simplest -- use case is to pass: -- -- > either (\e -> counterexample (show e) False) id . traceResult False -- -- as `monadicIOSim_` does. -- -> (forall s a. m s a -> IOSim s a) -- ^ natural transformation from `m` to @IOSim` s@ -> (forall s. PropertyM (m s) a) -> Property monadicIOSim f tr sim = property (runIOSimGen f (tr <$> monadic' sim)) -- | Like . -- -- @since 1.4.1.0 -- runIOSimGen :: (SimTrace a -> Property) -> (forall s. Gen (IOSim s a)) -> Gen Property runIOSimGen f sim = do Capture eval <- capture let trace = runSimTrace (eval sim) return (f trace)