Shake.hs

setValues state key file val = do

    currentValue <- HMap.lookup (file, Key key) <$> readVar state
    _ <- evaluate currentValue
    let fin = Just (hPutStrLn stderr "AN OLD VALUE GOT RELEASED")
    weak <- (evaluate >=> \v -> mkWeakPtr v fin) `traverse` currentValue


    modifyVar_ state $ \vals -> do
        -- Force to make sure the old HashMap is not retained
        evaluate $ HMap.insert (file, Key key) (fmap toDyn val) vals

    whenJust weak $ \w -> do
        performGC
        b <- deRefWeak w
        if isNothing b then hPutStrLn stderr "GONE AFTER INSERT" else do
            hPutStrLn stderr "DEREF VALUE STILL LIVES AFTER INSERT"

            updatedMap <- readVar state
            _ <- evaluate updatedMap

            performGC

            b <- deRefWeak w
            if (isNothing b) then hPutStrLn stderr "GONE AFTER EVALUATING THE MAP" else do
                hPutStrLn stderr "DEREF VALUE STILL LIVES AFTER EVALUATING THE MAP"

                _ <- evaluate $ HMap.lookup (file, Key key) updatedMap

                performGC
                b <- deRefWeak w
                if isNothing b then hPutStrLn stderr "GONE AFTER LOOKUP" else do
                    hPutStrLn stderr "DEREF VALUE STILL LIVES AFTER LOOKUP"

                    _ <- evaluate $ length $ show updatedMap

                    performGC
                    b <- deRefWeak w
                    if (isJust b)
                        then hPutStrLn stderr "DEREF VALUE STILL LIVES AFTER FORCING THE MAP"
                        else hPutStrLn stderr "GONE AFTER FORCING THE MAP"

Example output:

DEREF VALUE STILL LIVES AFTER INSERT
AN OLD VALUE GOT RELEASED
DEREF VALUE STILL LIVES AFTER EVALUATING THE MAP
DEREF VALUE STILL LIVES AFTER LOOKUP
DEREF VALUE STILL LIVES AFTER INSERT
DEREF VALUE STILL LIVES AFTER EVALUATING THE MAP
DEREF VALUE STILL LIVES AFTER LOOKUP
GONE AFTER FORCING THE MAP
AN OLD VALUE GOT RELEASED
AN OLD VALUE GOT RELEASED
GONE AFTER FORCING THE MAP
DEREF VALUE STILL LIVES AFTER INSERT
DEREF VALUE STILL LIVES AFTER EVALUATING THE MAP
DEREF VALUE STILL LIVES AFTER LOOKUP
GONE AFTER FORCING THE MAP
AN OLD VALUE GOT RELEASED
[DEBUG] Cancelled request IdInt 10
DEREF VALUE STILL LIVES AFTER INSERT
DEREF VALUE STILL LIVES AFTER EVALUATING THE MAP
DEREF VALUE STILL LIVES AFTER LOOKUP
GONE AFTER FORCING THE MAP
AN OLD VALUE GOT RELEASED
DEREF VALUE STILL LIVES AFTER INSERT
DEREF VALUE STILL LIVES AFTER EVALUATING THE MAP
DEREF VALUE STILL LIVES AFTER LOOKUP
GONE AFTER FORCING THE MAP
AN OLD VALUE GOT RELEASED
DEREF VALUE STILL LIVES AFTER INSERT
DEREF VALUE STILL LIVES AFTER EVALUATING THE MAP
DEREF VALUE STILL LIVES AFTER LOOKUP
GONE AFTER FORCING THE MAP
AN OLD VALUE GOT RELEASED
DEREF VALUE STILL LIVES AFTER INSERT
DEREF VALUE STILL LIVES AFTER EVALUATING THE MAP
DEREF VALUE STILL LIVES AFTER LOOKUP
GONE AFTER FORCING THE MAP
AN OLD VALUE GOT RELEASED
DEREF VALUE STILL LIVES AFTER INSERT
DEREF VALUE STILL LIVES AFTER EVALUATING THE MAP
DEREF VALUE STILL LIVES AFTER LOOKUP
GONE AFTER FORCING THE MAP
AN OLD VALUE GOT RELEASED
DEREF VALUE STILL LIVES AFTER INSERT
DEREF VALUE STILL LIVES AFTER EVALUATING THE MAP
DEREF VALUE STILL LIVES AFTER LOOKUP
GONE AFTER FORCING THE MAP
AN OLD VALUE GOT RELEASED
DEREF VALUE STILL LIVES AFTER INSERT
DEREF VALUE STILL LIVES AFTER EVALUATING THE MAP
DEREF VALUE STILL LIVES AFTER LOOKUP
GONE AFTER FORCING THE MAP
AN OLD VALUE GOT RELEASED
DEREF VALUE STILL LIVES AFTER INSERT
DEREF VALUE STILL LIVES AFTER EVALUATING THE MAP
DEREF VALUE STILL LIVES AFTER LOOKUP
GONE AFTER FORCING THE MAP
AN OLD VALUE GOT RELEASED
DEREF VALUE STILL LIVES AFTER INSERT
DEREF VALUE STILL LIVES AFTER EVALUATING THE MAP
DEREF VALUE STILL LIVES AFTER LOOKUP
GONE AFTER FORCING THE MAP
AN OLD VALUE GOT RELEASED
DEREF VALUE STILL LIVES AFTER INSERT
DEREF VALUE STILL LIVES AFTER EVALUATING THE MAP
DEREF VALUE STILL LIVES AFTER LOOKUP
GONE AFTER FORCING THE MAP
AN OLD VALUE GOT RELEASED
DEREF VALUE STILL LIVES AFTER INSERT
DEREF VALUE STILL LIVES AFTER EVALUATING THE MAP
DEREF VALUE STILL LIVES AFTER LOOKUP
GONE AFTER FORCING THE MAP
AN OLD VALUE GOT RELEASED
DEREF VALUE STILL LIVES AFTER INSERT
DEREF VALUE STILL LIVES AFTER EVALUATING THE MAP
DEREF VALUE STILL LIVES AFTER LOOKUP
GONE AFTER FORCING THE MAP
AN OLD VALUE GOT RELEASED
DEREF VALUE STILL LIVES AFTER INSERT
DEREF VALUE STILL LIVES AFTER EVALUATING THE MAP
DEREF VALUE STILL LIVES AFTER LOOKUP
GONE AFTER FORCING THE MAP
AN OLD VALUE GOT RELEASED
DEREF VALUE STILL LIVES AFTER INSERT
DEREF VALUE STILL LIVES AFTER EVALUATING THE MAP
DEREF VALUE STILL LIVES AFTER LOOKUP
GONE AFTER FORCING THE MAP
AN OLD VALUE GOT RELEASED
DEREF VALUE STILL LIVES AFTER INSERT
DEREF VALUE STILL LIVES AFTER EVALUATING THE MAP
DEREF VALUE STILL LIVES AFTER LOOKUP
GONE AFTER FORCING THE MAP
AN OLD VALUE GOT RELEASED
DEREF VALUE STILL LIVES AFTER INSERT
DEREF VALUE STILL LIVES AFTER INSERT
DEREF VALUE STILL LIVES AFTER EVALUATING THE MAP
DEREF VALUE STILL LIVES AFTER INSERT
DEREF VALUE STILL LIVES AFTER EVALUATING THE MAP
DEREF VALUE STILL LIVES AFTER LOOKUP
DEREF VALUE STILL LIVES AFTER INSERT
DEREF VALUE STILL LIVES AFTER INSERT
DEREF VALUE STILL LIVES AFTER EVALUATING THE MAP
DEREF VALUE STILL LIVES AFTER LOOKUP
DEREF VALUE STILL LIVES AFTER EVALUATING THE MAP
DEREF VALUE STILL LIVES AFTER EVALUATING THE MAP
DEREF VALUE STILL LIVES AFTER LOOKUP
DEREF VALUE STILL LIVES AFTER LOOKUP
DEREF VALUE STILL LIVES AFTER LOOKUP
GONE AFTER FORCING THE MAP
GONE AFTER FORCING THE MAP
GONE AFTER FORCING THE MAP
GONE AFTER FORCING THE MAP
GONE AFTER FORCING THE MAP
AN OLD VALUE GOT RELEASED
AN OLD VALUE GOT RELEASED
AN OLD VALUE GOT RELEASED
AN OLD VALUE GOT RELEASED
AN OLD VALUE GOT RELEASED
DEREF VALUE STILL LIVES AFTER INSERT
DEREF VALUE STILL LIVES AFTER INSERT
DEREF VALUE STILL LIVES AFTER EVALUATING THE MAP
DEREF VALUE STILL LIVES AFTER INSERT
DEREF VALUE STILL LIVES AFTER LOOKUP
DEREF VALUE STILL LIVES AFTER INSERT
DEREF VALUE STILL LIVES AFTER EVALUATING THE MAP
DEREF VALUE STILL LIVES AFTER EVALUATING THE MAP
DEREF VALUE STILL LIVES AFTER INSERT
DEREF VALUE STILL LIVES AFTER EVALUATING THE MAP
DEREF VALUE STILL LIVES AFTER LOOKUP
DEREF VALUE STILL LIVES AFTER LOOKUP
DEREF VALUE STILL LIVES AFTER EVALUATING THE MAP
DEREF VALUE STILL LIVES AFTER LOOKUP
DEREF VALUE STILL LIVES AFTER LOOKUP
GONE AFTER FORCING THE MAP
GONE AFTER FORCING THE MAP
GONE AFTER FORCING THE MAP
GONE AFTER FORCING THE MAP
GONE AFTER FORCING THE MAP
AN OLD VALUE GOT RELEASED
AN OLD VALUE GOT RELEASED
AN OLD VALUE GOT RELEASED
AN OLD VALUE GOT RELEASED
AN OLD VALUE GOT RELEASED
DEREF VALUE STILL LIVES AFTER INSERT
DEREF VALUE STILL LIVES AFTER EVALUATING THE MAP
DEREF VALUE STILL LIVES AFTER LOOKUP
DEREF VALUE STILL LIVES AFTER INSERT
DEREF VALUE STILL LIVES AFTER EVALUATING THE MAP
DEREF VALUE STILL LIVES AFTER LOOKUP
DEREF VALUE STILL LIVES AFTER FORCING THE MAP
AN OLD VALUE GOT RELEASED
DEREF VALUE STILL LIVES AFTER INSERT
DEREF VALUE STILL LIVES AFTER EVALUATING THE MAP
DEREF VALUE STILL LIVES AFTER LOOKUP
GONE AFTER FORCING THE MAP
AN OLD VALUE GOT RELEASED
DEREF VALUE STILL LIVES AFTER INSERT
DEREF VALUE STILL LIVES AFTER EVALUATING THE MAP
DEREF VALUE STILL LIVES AFTER LOOKUP
GONE AFTER FORCING THE MAP
AN OLD VALUE GOT RELEASED
AN OLD VALUE GOT RELEASED
GONE AFTER FORCING THE MAP
DEREF VALUE STILL LIVES AFTER INSERT
DEREF VALUE STILL LIVES AFTER EVALUATING THE MAP
DEREF VALUE STILL LIVES AFTER LOOKUP
GONE AFTER FORCING THE MAP
AN OLD VALUE GOT RELEASED
DEREF VALUE STILL LIVES AFTER INSERT
DEREF VALUE STILL LIVES AFTER EVALUATING THE MAP
DEREF VALUE STILL LIVES AFTER LOOKUP
GONE AFTER FORCING THE MAP
AN OLD VALUE GOT RELEASED
DEREF VALUE STILL LIVES AFTER INSERT
DEREF VALUE STILL LIVES AFTER EVALUATING THE MAP
DEREF VALUE STILL LIVES AFTER LOOKUP
GONE AFTER FORCING THE MAP
AN OLD VALUE GOT RELEASED
DEREF VALUE STILL LIVES AFTER INSERT
DEREF VALUE STILL LIVES AFTER EVALUATING THE MAP
DEREF VALUE STILL LIVES AFTER LOOKUP
GONE AFTER FORCING THE MAP
AN OLD VALUE GOT RELEASED
DEREF VALUE STILL LIVES AFTER INSERT
DEREF VALUE STILL LIVES AFTER EVALUATING THE MAP
DEREF VALUE STILL LIVES AFTER LOOKUP
GONE AFTER FORCING THE MAP
AN OLD VALUE GOT RELEASED