Overloaded functions with better MismatchedABI messaging

Author: reedsa

docs/web3.contract.rst

@@ -1570,6 +1570,23 @@ You can interact with the web3.py contract API as follows:
 Invoke Ambiguous Contract Functions
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
+Calling overloaded functions can be done as you would expect. Passing arguments will
+disambiguate which function you want to call.
+
+For example, if you have a contract with two functions with the name ``identity`` that
+accept different types of arguments, you can call them like this:
+
+.. code-block:: python
+
+    >>> ambiguous_contract = w3.eth.contract(address=..., abi=...)
+    >>> ambiguous_contract.functions.identity(1, True).call()
+    1
+    >>> ambiguous_contract.functions.identity("one", 1, True).call()
+    1
+
+If there is a need to first retrieve the function, you can use the contract instance's
+``get_function_by_signature`` method to get the function you want to call.
+
 Below is an example of a contract that has multiple functions of the same name,
 and the arguments are ambiguous. You can use the :meth:`Contract.get_function_by_signature`
 method to reference the intended function and call it with the correct arguments.
@@ -1588,7 +1605,6 @@ method to reference the intended function and call it with the correct arguments
         }
         """
         # fast forward all the steps of compiling and deploying the contract.
-        >>> ambiguous_contract.functions.identity(1, True) # raises Web3ValidationError
 
         >>> identity_func = ambiguous_contract.get_function_by_signature('identity(uint256,bool)')
         >>> identity_func(1, True)

newsfragments/3491.bugfix.rst

@@ -0,0 +1 @@
+Update the `ContractEvents` class to raise a `NoABIFound` exception if the `Contract` is initialized without an `ABI` and an attempt to access an event is made. This exception makes `ContractEvents` consistent with `ContractFunctions`.

newsfragments/3491.feature.rst

@@ -0,0 +1 @@
+Contracts with overloaded functions or events are now supported. The Contract initializes functions and events using an identifier to distinguish between them. The identifier is the function or event signature, which consists of the name and the parameter types.

newsfragments/3491.misc.rst

@@ -0,0 +1 @@
+Raise MismatchedABI exceptions with detailed error messaging about potential matching elements. The arguments and expected types are included in the exception message for better debugging.

tests/core/contracts/conftest.py

@@ -10,6 +10,9 @@
 from tests.utils import (
     async_partial,
 )
+from web3._utils.abi import (
+    get_abi_element_signature,
+)
 from web3._utils.contract_sources.contract_data.arrays_contract import (
     ARRAYS_CONTRACT_DATA,
 )
@@ -22,6 +25,7 @@
     CONTRACT_CALLER_TESTER_DATA,
 )
 from web3._utils.contract_sources.contract_data.event_contracts import (
+    AMBIGUOUS_EVENT_NAME_CONTRACT_DATA,
     EVENT_CONTRACT_DATA,
     INDEXED_EVENT_CONTRACT_DATA,
 )
@@ -61,6 +65,10 @@
 from web3.exceptions import (
     Web3ValueError,
 )
+from web3.utils.abi import (
+    abi_to_signature,
+    get_abi_element,
+)
 
 # --- function name tester contract --- #
 
@@ -283,6 +291,30 @@ def indexed_event_contract(
     return indexed_event_contract
 
 
+@pytest.fixture
+def ambiguous_event_contract(
+    w3, wait_for_block, wait_for_transaction, address_conversion_func
+):
+    wait_for_block(w3)
+
+    ambiguous_event_contract_factory = w3.eth.contract(
+        **AMBIGUOUS_EVENT_NAME_CONTRACT_DATA
+    )
+    deploy_txn_hash = ambiguous_event_contract_factory.constructor().transact(
+        {"gas": 1000000}
+    )
+    deploy_receipt = wait_for_transaction(w3, deploy_txn_hash)
+    contract_address = address_conversion_func(deploy_receipt["contractAddress"])
+
+    bytecode = w3.eth.get_code(contract_address)
+    assert bytecode == ambiguous_event_contract_factory.bytecode_runtime
+    ambiguous_event_name_contract = ambiguous_event_contract_factory(
+        address=contract_address
+    )
+    assert ambiguous_event_name_contract.address == contract_address
+    return ambiguous_event_name_contract
+
+
 # --- arrays contract --- #
 
 
@@ -470,6 +502,11 @@ def invoke_contract(
     func_kwargs=None,
     tx_params=None,
 ):
+    function_signature = contract_function
+    function_arg_count = len(func_args or ()) + len(func_kwargs or {})
+    if function_arg_count == 0:
+        function_signature = get_abi_element_signature(contract_function)
+
     if func_args is None:
         func_args = []
     if func_kwargs is None:
@@ -482,7 +519,14 @@ def invoke_contract(
             f"allowable_invoke_method must be one of: {allowable_call_desig}"
         )
 
-    function = contract.functions[contract_function]
+    fn_abi = get_abi_element(
+        contract.abi,
+        function_signature,
+        *func_args,
+        abi_codec=contract.w3.codec,
+        **func_kwargs,
+    )
+    function = contract.functions[abi_to_signature(fn_abi)]
     result = getattr(function(*func_args, **func_kwargs), api_call_desig)(tx_params)
 
     return result
@@ -744,6 +788,11 @@ async def async_invoke_contract(
     func_kwargs=None,
     tx_params=None,
 ):
+    function_signature = contract_function
+    function_arg_count = len(func_args or ()) + len(func_kwargs or {})
+    if function_arg_count == 0:
+        function_signature = get_abi_element_signature(contract_function)
+
     if func_args is None:
         func_args = []
     if func_kwargs is None:
@@ -756,7 +805,14 @@ async def async_invoke_contract(
             f"allowable_invoke_method must be one of: {allowable_call_desig}"
         )
 
-    function = contract.functions[contract_function]
+    fn_abi = get_abi_element(
+        contract.abi,
+        function_signature,
+        *func_args,
+        abi_codec=contract.w3.codec,
+        **func_kwargs,
+    )
+    function = contract.functions[abi_to_signature(fn_abi)]
     result = await getattr(function(*func_args, **func_kwargs), api_call_desig)(
         tx_params
     )