Fix a race condition

DaveBarton · Nov 11, 2023 · 209f604 · 209f604
1 parent e28463a
commit 209f604
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Showing 2 changed files with 6 additions and 5 deletions.
diff --git a/calculi.cabal b/calculi.cabal
@@ -53,6 +53,7 @@ library
         async,
         -- fmt >= 0.4,
         ghc-trace-events,
+        -- hashable, unordered-containers,
         -- inspection-testing >= 0.3,
         mod,
         -- poly >= 0.5.1, deepseq, finite-typelits, vector-sized,

diff --git a/src/Math/Algebra/Commutative/GroebnerBasis.hs b/src/Math/Algebra/Commutative/GroebnerBasis.hs
@@ -663,13 +663,13 @@ groebnerBasis gbpA@(GBPolyOps { .. }) gbTrace gbi0 newGens  = TS.scope $ do
                             writeTVar ijcsRef $! {- TS.measurePure "1.3.1 skipIJCs" $ -}
                                 Set.difference ijcs skipIJCs
                             pure ijcs
-                        ijcs'       <- {- TS.measureM "1.4 addITCs" $ -} atomically $ do
-                            ijcs1       <- readTVar ijcsRef
-                            let ijcs'   = {- TS.measurePure "1.4.1 addITCs" $ -}
+                        (ijcs1, ijcs')  <- {- TS.measureM "1.4 addITCs" $ -} atomically $ do
+                            ijcs1           <- readTVar ijcsRef
+                            let ijcs'       = {- TS.measurePure "1.4.1 addITCs" $ -}
                                     Set.union ijcs1 addITCs
                             writeTVar ijcsRef ijcs'
-                            pure ijcs'
-                        when (null ijcs && not (null ijcs')) $ inc1TVar wakeAllThreads
+                            pure (ijcs1, ijcs')
+                        when (null ijcs1 && not (null ijcs')) $ inc1TVar wakeAllThreads
                         when (gbTrace .&. gbTQueues /= 0) $ do
                             let n       = Set.size ijcs
                                 n'      = Set.size ijcs'