Add support for reaching receive

lib/Echidna/ABI.hs

@@ -47,7 +47,10 @@ import Echidna.Types.Signature
 
 -- | Fallback function is the null string
 fallback :: SolSignature
-fallback = ("",[])
+fallback = ("*fallback*",[])
+
+receive :: SolSignature
+receive = ("*receive*",[])
 
 commonTypeSizes :: [Int]
 commonTypeSizes = [8,16..256]

lib/Echidna/Solidity.hs

@@ -25,7 +25,7 @@ import System.Exit                (ExitCode(..))
 import System.Directory           (doesDirectoryExist, doesFileExist, findExecutable, listDirectory, removeFile)
 import System.FilePath.Posix      ((</>))
 
-import Echidna.ABI                (encodeSig, encodeSigWithName, hashSig, fallback, commonTypeSizes, mkValidAbiInt, mkValidAbiUInt)
+import Echidna.ABI                (encodeSig, encodeSigWithName, hashSig, fallback, receive, commonTypeSizes, mkValidAbiInt, mkValidAbiUInt)
 import Echidna.Exec               (execTx, initialVM)
 import Echidna.Events             (EventMap)
 import Echidna.Test               (createTests, isAssertionMode, isPropertyMode)
@@ -144,7 +144,7 @@ filterMethods cn f@(Blacklist ig) ms = case NE.filter (\s -> encodeSigWithName c
                                          fs -> NE.fromList fs
 
 abiOf :: Text -> SolcContract -> NE.NonEmpty SolSignature
-abiOf pref cc = fallback NE.:| filter (not . isPrefixOf pref . fst) (elems (cc ^. abiMap) <&> \m -> (m ^. methodName, m ^.. methodInputs . traverse . _2))
+abiOf pref cc = fallback NE.<| (receive NE.:| filter (not . isPrefixOf pref . fst) (elems (cc ^. abiMap) <&> \m -> (m ^. methodName, m ^.. methodInputs . traverse . _2)))
 
 -- | Given an optional contract name and a list of 'SolcContract's, try to load the specified
 -- contract, or, if not provided, the first contract in the list, into a 'VM' usable for Echidna

lib/Echidna/Transaction.hs

@@ -153,10 +153,12 @@ setupTx (Tx c s r g gp v (t, b)) = liftSH . sequence_ $
   , tx . gasprice .= gp, tx . origin .= s, state . caller .= litAddr s, state . callvalue .= litWord v
   , block . timestamp += litWord t, block . number += b, setup] where
     setup = case c of
-      SolCreate bc   -> assign (env . contracts . at r) (Just $ initialContract (InitCode (ConcreteBuffer bc)) & set balance v) >> loadContract r >> state . code .= ConcreteBuffer bc
-      SolCall cd     -> incrementBalance >> loadContract r >> state . calldata .= concreteCalldata (encode cd)
-      SolCalldata cd -> incrementBalance >> loadContract r >> state . calldata .= concreteCalldata cd
-      NoCall         -> error "NoCall"
+      SolCreate bc             -> assign (env . contracts . at r) (Just $ initialContract (InitCode (ConcreteBuffer bc)) & set balance v) >> loadContract r >> state . code .= ConcreteBuffer bc
+      SolCall ("*receive*",_)  -> incrementBalance >> loadContract r >> state . calldata .= concreteCalldata ""
+      SolCall ("*fallback*",_) -> incrementBalance >> loadContract r >> state . calldata .= concreteCalldata "\0"
+      SolCall cd               -> incrementBalance >> loadContract r >> state . calldata .= concreteCalldata (encode cd)
+      SolCalldata cd           -> incrementBalance >> loadContract r >> state . calldata .= concreteCalldata cd
+      NoCall                   -> error "NoCall"
     incrementBalance = (env . contracts . ix r . balance) += v
     encode (n, vs) = abiCalldata
       (encodeSig (n, abiValueType <$> vs)) $ V.fromList vs

src/test/Tests/Integration.hs

@@ -59,8 +59,6 @@ integrationTests = testGroup "Solidity Integration Testing"
       [ ("echidna_library_call failed",            solved      "echidna_library_call")
       , ("echidna_valid_timestamp failed",         passed      "echidna_valid_timestamp") 
       ]
-  , testContractV "basic/fallback.sol"   (Just (< solcV (0,6,0))) Nothing
-      [ ("echidna_fallback failed",                solved      "echidna_fallback") ]
   , testContract "basic/push_long.sol" (Just "basic/push_long.yaml")
       [ ("test_long_5 passed",                     solvedWithout NoCall "test_long_5")]
   , testContract "basic/propGasLimit.sol" (Just "basic/propGasLimit.yaml")

src/test/Tests/Values.hs

@@ -2,7 +2,7 @@ module Tests.Values (valuesTests) where
 
 import Test.Tasty (TestTree, testGroup)
 
-import Common (testContract, testContract', solved, solvedLen)
+import Common (testContract, testContract', testContractV, solcV, solved, solvedLen)
 
 valuesTests :: TestTree
 valuesTests = testGroup "Value extraction tests"
@@ -33,5 +33,7 @@ valuesTests = testGroup "Value extraction tests"
     , testContract "values/darray.sol"       Nothing
       [ ("echidna_darray passed",                  solved      "echidna_darray")
       , ("echidna_darray didn't shrink optimally", solvedLen 1 "echidna_darray") ]
-
+    , testContractV "values/receive.sol"   (Just (>= solcV (0,6,0))) Nothing
+      [ ("echidna_fallback failed",                solved      "echidna_fallback") 
+      , ("echidna_receive failed",                 solved      "echidna_receive") ]
   ]

tests/solidity/values/receive.sol

@@ -0,0 +1,22 @@
+pragma solidity ^0.6.0;
+
+contract Receive {
+  bool found_fallback = false;
+  bool found_receive = false;
+
+  function echidna_found_fallback() public view returns (bool) {
+    return(!found_fallback);
+  }
+
+  function echidna_found_receive() public view returns (bool) {
+    return(!found_receive);
+  }
+
+  fallback() external payable {
+    found_fallback = true;
+  } 
+
+  receive() external payable {
+    found_receive = true;
+  } 
+}