Wrap fetch exceptions (#971)

crytic · Mar 7, 2023 · d58a3b4 · d58a3b4
1 parent fef5dae
commit d58a3b4
Showing 1 changed file with 16 additions and 3 deletions.
diff --git a/lib/Echidna/Exec.hs b/lib/Echidna/Exec.hs
@@ -6,7 +6,7 @@ module Echidna.Exec where
 
 import Control.Lens
 import Control.Monad (when)
-import Control.Monad.Catch (MonadThrow(..))
+import Control.Monad.Catch (MonadThrow(..), catchAll, SomeException)
 import Control.Monad.State.Strict (MonadState(get, put), execState, runStateT, MonadIO(liftIO))
 import Control.Monad.Reader (MonadReader, asks)
 import Data.IORef (readIORef, atomicWriteIORef)
@@ -111,7 +111,7 @@ execTxWith l onErr executeTx tx = do
             getRpcUrl >>= \case
               Just rpcUrl -> do
                 rpcBlock <- getRpcBlock
-                ret <- liftIO $ EVM.Fetch.fetchContractFrom rpcBlock rpcUrl addr
+                ret <- liftIO $ safeFetchContractFrom rpcBlock rpcUrl addr
                 case ret of
                   -- TODO: fix hevm to not return an empty contract in case of an error
                   Just contract | contract._contractcode /= EVM.RuntimeCode (EVM.ConcreteRuntimeCode "") -> do
@@ -153,7 +153,7 @@ execTxWith l onErr executeTx tx = do
             getRpcUrl >>= \case
               Just rpcUrl -> do
                 rpcBlock <- getRpcBlock
-                ret <- liftIO $ EVM.Fetch.fetchSlotFrom rpcBlock rpcUrl addr slot
+                ret <- liftIO $ safeFetchSlotFrom rpcBlock rpcUrl addr slot
                 case ret of
                   Just value -> do
                     l %= execState (continuation value)
@@ -188,12 +188,25 @@ execTxWith l onErr executeTx tx = do
     getRpcUrl = liftIO $ do
       val <- lookupEnv "ECHIDNA_RPC_URL"
       pure (Text.pack <$> val)
+
     getRpcBlock = liftIO $ do
       -- TODO: Is the latest block a good default? It makes fuzzing hard to
       -- reproduce. Rethink this.
       val <- lookupEnv "ECHIDNA_RPC_BLOCK"
       pure $ maybe EVM.Fetch.Latest EVM.Fetch.BlockNumber (val >>= readMaybe)
 
+    -- TODO: temporary solution, handle errors gracefully
+    safeFetchContractFrom rpcBlock rpcUrl addr =
+      catchAll
+        (EVM.Fetch.fetchContractFrom rpcBlock rpcUrl addr)
+        (\(_e :: SomeException) -> pure $ Just emptyAccount)
+
+    -- TODO: temporary solution, handle errors gracefully
+    safeFetchSlotFrom rpcBlock rpcUrl addr slot =
+      catchAll
+        (EVM.Fetch.fetchSlotFrom rpcBlock rpcUrl addr slot)
+        (\(_e :: SomeException) -> pure $ Just 0)
+
   -- | Handles reverts, failures and contract creations that might be the result
   -- (`vmResult`) of executing transaction `tx`.
   handleErrorsAndConstruction vmResult vmBeforeTx = case (vmResult, tx.call) of