Don't fail when outgoing message amounts sum to more than current balance

src/eval/Eval.ml

@@ -900,16 +900,11 @@ let post_process_msgs cstate outs =
     List.fold_left amounts ~init:zero ~f:(fun z a -> add z a)
   in
   let open ContractState in
-  if compare cstate.balance to_be_transferred < 0 then
-    fail0
-    @@ sprintf
-         "The balance is too low (%s) to transfer all the funds in the \
-          messages (%s)"
-         (to_string cstate.balance)
-         (to_string to_be_transferred)
-  else
-    let balance = sub cstate.balance to_be_transferred in
-    pure { cstate with balance }
+  let balance =
+    if compare cstate.balance to_be_transferred < 0 then Uint128.zero
+    else sub cstate.balance to_be_transferred
+  in
+  pure { cstate with balance }
 
 (* 
 Handle message:

tests/checker/good/gold/multiple-msgs.scilla.gold

@@ -5,7 +5,10 @@
     "vname": "HelloWorld",
     "params": [],
     "fields": [],
-    "transitions": [ { "vname": "multipleMsgs", "params": [] } ],
+    "transitions": [
+      { "vname": "multipleMsgs", "params": [] },
+      { "vname": "multipleAmountMsgs", "params": [] }
+    ],
     "procedures": [],
     "events": [],
     "ADTs": [

tests/contracts/multiple-msgs.scilla

@@ -29,3 +29,11 @@ transition multipleMsgs()
   msgs2 = Cons {Message} msg2 msgs1;
   send msgs2
 end
+
+transition multipleAmountMsgs()
+  msg1 = {_tag : ""; _recipient : _sender; _amount : Uint128 100};
+  msg2 = {_tag : ""; _recipient : _sender; _amount : Uint128 100};
+  msgs1 = one_msg msg1;
+  msgs2 = Cons {Message} msg2 msgs1;
+  send msgs2
+end

tests/runner/Testcontracts.ml

@@ -412,7 +412,7 @@ let contract_tests env =
                 >::: build_contract_tests env "map_corners_test" succ_code 51 53
                        [];
                 "multiple_msgs_test"
-                >::: build_contract_tests env "multiple-msgs" succ_code 1 1 [];
+                >::: build_contract_tests env "multiple-msgs" succ_code 1 3 [];
                 "listiter"
                 >::: build_contract_tests env "listiter" succ_code 1 1 [];
                 "polynetwork"

tests/runner/multiple-msgs/blockchain_2.json

@@ -0,0 +1 @@
+[ { "vname": "BLOCKNUMBER", "type": "BNum", "value": "100" } ]

tests/runner/multiple-msgs/blockchain_3.json

@@ -0,0 +1 @@
+[ { "vname": "BLOCKNUMBER", "type": "BNum", "value": "100" } ]

tests/runner/multiple-msgs/message_2.json

@@ -0,0 +1,7 @@
+{
+    "_tag": "multipleAmountMsgs",
+    "_amount": "0",
+    "_sender": "0x1234567890123456789012345678906784567890",
+    "params": [],
+    "_origin": "0x1234567890123456789012345678906784567890"
+}

tests/runner/multiple-msgs/message_3.json

@@ -0,0 +1,7 @@
+{
+    "_tag": "multipleAmountMsgs",
+    "_amount": "0",
+    "_sender": "0x1234567890123456789012345678906784567890",
+    "params": [],
+    "_origin": "0x1234567890123456789012345678906784567890"
+}

tests/runner/multiple-msgs/output_2.json

@@ -0,0 +1,21 @@
+{
+  "scilla_major_version": "0",
+  "gas_remaining": "7938",
+  "_accepted": "false",
+  "messages": [
+    {
+      "_tag": "",
+      "_amount": "100",
+      "_recipient": "0x1234567890123456789012345678906784567890",
+      "params": []
+    },
+    {
+      "_tag": "",
+      "_amount": "100",
+      "_recipient": "0x1234567890123456789012345678906784567890",
+      "params": []
+    }
+  ],
+  "states": [ { "vname": "_balance", "type": "Uint128", "value": "0" } ],
+  "events": []
+}

tests/runner/multiple-msgs/output_3.json

@@ -0,0 +1,21 @@
+{
+  "scilla_major_version": "0",
+  "gas_remaining": "7938",
+  "_accepted": "false",
+  "messages": [
+    {
+      "_tag": "",
+      "_amount": "100",
+      "_recipient": "0x1234567890123456789012345678906784567890",
+      "params": []
+    },
+    {
+      "_tag": "",
+      "_amount": "100",
+      "_recipient": "0x1234567890123456789012345678906784567890",
+      "params": []
+    }
+  ],
+  "states": [ { "vname": "_balance", "type": "Uint128", "value": "50" } ],
+  "events": []
+}

tests/runner/multiple-msgs/state_2.json

@@ -0,0 +1,5 @@
+[
+    { "vname": "_balance",
+      "type": "Uint128",
+      "value": "150" }
+]

tests/runner/multiple-msgs/state_3.json

@@ -0,0 +1,5 @@
+[
+    { "vname": "_balance",
+      "type": "Uint128",
+      "value": "250" }
+]