feat: make send() gas stipend configurable (#3158)

make gas stipend configurable so that users can `send()` to contracts
instead of resorting to `raw_call()`

Author: emc415

tests/parser/functions/test_send.py

@@ -56,3 +56,37 @@ def __default__():
     assert receiver.last_sender() == sender.address
     assert w3.eth.get_balance(sender.address) == 0
     assert w3.eth.get_balance(receiver.address) == 1
+
+
+def test_send_gas_stipend(get_contract, w3):
+    """
+    Tests to verify that adding gas stipend to send() will send sufficient gas
+    """
+
+    sender_code = """
+
+@external
+def test_send_stipend(receiver: address):
+    send(receiver, 1, gas=50000)
+    """
+
+    # default function writes variable, this requires more gas than
+    # send would pass without gas stipend
+    receiver_code = """
+last_sender: public(address)
+
+@external
+@payable
+def __default__():
+    self.last_sender = msg.sender
+    """
+
+    sender = get_contract(sender_code, value=1)
+    receiver = get_contract(receiver_code)
+
+    sender.test_send_stipend(receiver.address, transact={"gas": 100000})
+
+    # value transfer hapenned, variable was changed
+    assert receiver.last_sender() == sender.address
+    assert w3.eth.get_balance(sender.address) == 0
+    assert w3.eth.get_balance(receiver.address) == 1

tests/parser/syntax/test_send.py

@@ -58,6 +58,44 @@ def foo():
     """,
         TypeMismatch,
     ),
+    # Tests for sending gas stipend
+    (
+        """
+@external
+def foo():
+    send(0x1234567890123456789012345678901234567890, 5, gas=1.5)
+    """,
+        InvalidType,
+    ),
+    (
+        """
+@external
+def foo():
+    send(0x1234567890123456789012345678901234567890, 5, gas=-2)
+    """,
+        InvalidType,
+    ),
+    (
+        """
+x: int128
+
+@external
+def foo():
+    send(0x1234567890123456789012345678901234567890, 5, gas=self.x)
+    """,
+        TypeMismatch,
+    ),
+    (
+        """
+x: decimal
+
+@external
+def foo():
+    send(0x1234567890123456789012345678901234567890, 5, gas=self.x)
+    """,
+        TypeMismatch,
+    ),
+    # End tests for sending gas stipend
 ]
 
 
@@ -109,6 +147,20 @@ def send(a: address, w: uint256):
 def foo():
     self.send(msg.sender, msg.value)
     """,
+    """
+#Test send gas stipend
+@external
+def foo():
+    send(0xde0B295669a9FD93d5F28D9Ec85E40f4cb697BAe, 5, gas=5000)
+    """,
+    """
+x: uint256
+
+#Test send gas stipend
+@external
+def foo():
+    send(0xde0B295669a9FD93d5F28D9Ec85E40f4cb697BAe, 5, gas=self.x)
+    """,
 ]
 
 

vyper/builtins/functions.py

@@ -1246,13 +1246,16 @@ class Send(BuiltinFunction):
 
     _id = "send"
     _inputs = [("to", AddressT()), ("value", UINT256_T)]
+    # default gas stipend is 0
+    _kwargs = {"gas": KwargSettings(UINT256_T, 0)}
     _return_type = None
 
     @process_inputs
     def build_IR(self, expr, args, kwargs, context):
         to, value = args
+        gas = kwargs["gas"]
         context.check_is_not_constant("send ether", expr)
-        return IRnode.from_list(["assert", ["call", 0, to, value, 0, 0, 0, 0]])
+        return IRnode.from_list(["assert", ["call", gas, to, value, 0, 0, 0, 0]])
 
 
 class SelfDestruct(BuiltinFunction):