Self-review

boa/contracts/abi/__init__.py

@@ -1,28 +1,66 @@
-from typing import Any, Union
+from collections import defaultdict
+from typing import Any, Callable, Iterable, TypeVar, Union
 
 from boa.environment import Address
 
+T = TypeVar("T")
+K = TypeVar("K")
+
 
 def _encode_addresses(values: list) -> list:
+    """
+    Converts any object with an 'address' field into the address itself.
+    This is to allow `Address` objects to be used.
+    :param values: A list of values
+    :return: The same list of values, with addresses converted.
+    """
     return [getattr(arg, "address", arg) for arg in values]
 
 
 def _decode_addresses(abi_type: Union[list, str], decoded: Any) -> Any:
+    """
+    Converts addresses received from the EVM into `Address` objects, recursively.
+    :param abi_type: ABI type name. This should be a list if `decoded` is also a list.
+    :param decoded: The decoded value(s) from the EVM.
+    :return: The same value(s), with addresses converted.
+    """
     if abi_type == "address":
         return Address(decoded)
     if isinstance(abi_type, str) and abi_type.startswith("address["):
         return [Address(i) for i in decoded]
     return decoded
 
 
-def _parse_abi_type(abi: dict) -> list:
+def _parse_abi_type(abi: dict) -> Union[list, str]:
+    """
+    Parses an ABI type into a list of types.
+    :param abi: The ABI type to parse.
+    :return: A list of types or a single type.
+    """
     if "components" in abi:
+        assert abi["type"] == "tuple"  # sanity check
         return [_parse_abi_type(item) for item in abi["components"]]
     return abi["type"]
 
 
 def _format_abi_type(types: list) -> str:
+    """
+    Converts a list of ABI types into a comma-separated string.
+    """
     return ",".join(
         item if isinstance(item, str) else f"({_format_abi_type(item)})"
         for item in types
     )
+
+
+def group_by(sequence: Iterable[T], key: Callable[[T], K]) -> dict[K, list[T]]:
+    """
+    Groups a sequence of items by a key function.
+    :param sequence: The sequence to group.
+    :param key: The key function.
+    :return: A dictionary mapping keys to a list of items with that key.
+    """
+    result = defaultdict(list)
+    for item in sequence:
+        result[key(item)].append(item)
+    return result

boa/contracts/abi/contract.py

@@ -1,12 +1,12 @@
 from functools import cached_property
-from itertools import groupby
+from operator import attrgetter
 from os.path import basename
-from typing import Any, Optional
+from typing import Any, Optional, Union
+from warnings import warn
 
-from _operator import attrgetter
 from eth.abc import ComputationAPI
 
-from boa.contracts.abi import _decode_addresses, _format_abi_type
+from boa.contracts.abi import _decode_addresses, _format_abi_type, group_by
 from boa.contracts.abi.function import ABIFunction, ABIOverload
 from boa.contracts.evm_contract import BaseEVMContract
 from boa.environment import Address
@@ -28,9 +28,15 @@ def __init__(
         super().__init__(env, filename=filename, address=address)
         self._name = name
         self._functions = functions
+        self._bytecode = self.env.vm.state.get_code(address.canonical_address)
+        if not self._bytecode:
+            warn(
+                f"Requested {self} but there is no bytecode at that address!",
+                stacklevel=2,
+            )
 
-        for name, group in groupby(self._functions, key=attrgetter("name")):
-            setattr(self, name, ABIOverload.create(list(group), self))
+        for name, group in group_by(self._functions, attrgetter("name")).items():
+            setattr(self, name, ABIOverload.create(group, self))
 
         self._address = Address(address)
 
@@ -48,7 +54,7 @@ def marshal_to_python(self, computation, abi_type: list[str]) -> tuple[Any, ...]
         :param computation: the computation object returned by `execute_code`
         :param abi_type: the ABI type of the return value.
         """
-        if computation.is_error:
+        if computation.is_error or (abi_type and not computation.output):
             return self.handle_error(computation)
 
         schema = f"({_format_abi_type(abi_type)})"
@@ -79,7 +85,8 @@ def deployer(self) -> "ABIContractFactory":
 
     def __repr__(self):
         file_str = f" (file {self.filename})" if self.filename else ""
-        return f"<{self._name} interface at {self.address}>{file_str}"
+        warn_str = "" if self._bytecode else " (WARNING: no bytecode at this address!)"
+        return f"<{self._name} interface at {self.address}{warn_str}>{file_str}"
 
 
 class ABIContractFactory:
@@ -103,20 +110,11 @@ def from_abi_dict(cls, abi, name="<anonymous contract>"):
         ]
         return cls(basename(name), functions, filename=name)
 
-    def at(self, address) -> ABIContract:
+    def at(self, address: Union[Address, str]) -> ABIContract:
         """
         Create an ABI contract object for a deployed contract at `address`.
         """
         address = Address(address)
-
-        ret = ABIContract(self._name, self._functions, address, self._filename)
-
-        bytecode = ret.env.vm.state.get_code(address.canonical_address)
-        if not bytecode:
-            raise ValueError(
-                f"Requested {ret} but there is no bytecode at that address!"
-            )
-
-        ret.env.register_contract(address, ret)
-
-        return ret
+        contract = ABIContract(self._name, self._functions, address, self._filename)
+        contract.env.register_contract(address, contract)
+        return contract

boa/contracts/abi/function.py

@@ -5,7 +5,7 @@
 from vyper.utils import method_id
 
 from boa.contracts.abi import _encode_addresses, _format_abi_type, _parse_abi_type
-from boa.util.abi import abi_decode, abi_encode, is_abi_encodable
+from boa.util.abi import abi_encode, is_abi_encodable
 
 if TYPE_CHECKING:
     from boa.contracts.abi.contract import ABIContract
@@ -73,13 +73,6 @@ def is_encodable(self, *args, **kwargs) -> bool:
             for abi_type, arg in zip(self.argument_types, parsed_args)
         )
 
-    def matches(self, *args, **kwargs) -> bool:
-        """Check whether this function matches the given arguments exactly."""
-        parsed_args = self._merge_kwargs(*args, **kwargs)
-        encoded_args = abi_encode(self.signature, args)
-        decoded_args = abi_decode(self.signature, encoded_args)
-        return map(type, parsed_args) == map(type, decoded_args)
-
     def _merge_kwargs(self, *args, **kwargs) -> list:
         """Merge positional and keyword arguments into a single list."""
         if len(kwargs) + len(args) != self.argument_count:
@@ -154,7 +147,7 @@ def name(self):
     def __call__(self, *args, **kwargs):
         """
         Call the function that matches the given arguments.
-        :raises Exception: if not a single function is found
+        :raises Exception: if a single function is not found
         """
         match [f for f in self.functions if f.is_encodable(*args, **kwargs)]:
             case [function]:

boa/profiling.py

@@ -150,7 +150,7 @@ def by_line(self):
         return ret
 
 
-# line profile. mergeable across contract
+# line profile. mergeable across contracts
 class LineProfile:
     def __init__(self):
         self.profile = {}
@@ -313,7 +313,7 @@ def get_call_profile_table(env: Env) -> Table:
             (cache[profile].net_gas_stats.avg_gas, profile.address)
         )
 
-    # arrange from most to least expensive contract:
+    # arrange from most to least expensive contracts:
     sort_gas = sorted(contract_vs_mean_gas, key=lambda x: x[0], reverse=True)
     sorted_addresses = list(set([x[1] for x in sort_gas]))
 
@@ -324,7 +324,7 @@ def get_call_profile_table(env: Env) -> Table:
         for profile in cached_contracts[address]:
             fn_vs_mean_gas.append((cache[profile].net_gas_stats.avg_gas, profile))
 
-        # arrange from most to least expensive contract:
+        # arrange from most to least expensive contracts:
         fn_vs_mean_gas = sorted(fn_vs_mean_gas, key=lambda x: x[0], reverse=True)
 
         for c, (_, profile) in enumerate(fn_vs_mean_gas):

boa/test/plugin.py

@@ -32,7 +32,7 @@ def pytest_addoption(parser):
     parser.addoption(
         "--gas-profile",
         action="store_true",
-        help="Profile gas used by contract called in tests",
+        help="Profile gas used by contracts called in tests",
     )
 
 

boa/util/exceptions.py

@@ -6,8 +6,8 @@
 # take an exception instance, and strip frames in the target module
 # from the traceback
 def strip_internal_frames(exc, module_name=None):
-    ei = sys.exc_info()
-    frame = ei[2].tb_frame
+    error_type, error, traceback = sys.exc_info()
+    frame = traceback.tb_frame
 
     if module_name is None:
         module_name = frame.f_globals["__name__"]
@@ -18,7 +18,7 @@ def strip_internal_frames(exc, module_name=None):
     # kwargs incompatible with pypy here
     # tb_next=None, tb_frame=frame, tb_lasti=frame.f_lasti, tb_lineno=frame.f_lineno
     tb = types.TracebackType(None, frame, frame.f_lasti, frame.f_lineno)
-    return ei[1].with_traceback(tb)
+    return error.with_traceback(tb)
 
 
 class StackTrace(list):
@@ -67,6 +67,9 @@ class BoaError(Exception):
     # stack trace but does not require the actual stack trace itself.
     def __str__(self):
         frame = self.stack_trace.last_frame
-        err = frame.vm_error
-        err.args = (frame.pretty_vm_reason, *err.args[1:])
+        if hasattr(frame, "vm_error"):
+            err = frame.vm_error
+            err.args = (frame.pretty_vm_reason, *err.args[1:])
+        else:
+            err = frame
         return f"{err}\n\n{self.stack_trace}"

tests/integration/fork/test_abi_contract.py

@@ -3,6 +3,9 @@
 from hypothesis import given
 
 import boa
+from boa.util.exceptions import BoaError
+
+ZERO_ADDRESS = "0x0000000000000000000000000000000000000000"
 
 
 @pytest.fixture(scope="module")
@@ -45,6 +48,14 @@ def test_tricrypto(tricrypto):
     # TODO: test the overloaded functions
 
 
+def test_no_bytecode(get_filepath):
+    abi_path = get_filepath("crvusd_abi.json")
+    crvusd = boa.load_abi(abi_path).at(ZERO_ADDRESS)
+    with pytest.raises(BoaError) as exc_info:
+        crvusd.decimals()
+    assert "no bytecode at this address" in str(exc_info.value)
+
+
 def test_invariants(crvusd):
     assert crvusd.decimals() == 18
     assert crvusd.version() == "v1.0.0"
@@ -57,7 +68,7 @@ def test_metaregistry_overloading(metaregistry):
     pool = metaregistry.pool_list(0)
     coin1, coin2 = metaregistry.get_coins(pool)[:2]
     pools_found = metaregistry.find_pools_for_coins(coin1, coin2)
-    first_pools = [pool for pool in pools_found if not pool.startswith("0x0000")][:10]
+    first_pools = [pool for pool in pools_found if not pool.startswith("0x0000")][:2]
     assert first_pools[0] == metaregistry.find_pool_for_coins(coin1, coin2)
     assert first_pools == [
         metaregistry.find_pool_for_coins(coin1, coin2, i)
@@ -80,13 +91,7 @@ def test_stableswap_factory_ng(stableswap_factory_ng):
         3,
         [0, 0, 0],
     )
-    assert stableswap_factory_ng.base_pool_data(pool) == (
-        "0x0000000000000000000000000000000000000000",
-        [],
-        0,
-        0,
-        [],
-    )
+    assert stableswap_factory_ng.base_pool_data(pool) == (ZERO_ADDRESS, [], 0, 0, [])
 
 
 # randomly grabbed from:

tests/unitary/test_abi.py

@@ -124,10 +124,8 @@ def test(a: uint128 = 0, b: uint128 = 0) -> uint128:
 
 
 def test_bad_address():
-    with pytest.raises(ValueError) as exc_info:
+    with pytest.warns(UserWarning, match=r"there is no bytecode at that address!$"):
         ABIContractFactory.from_abi_dict([]).at(boa.env.eoa)
-    (error,) = exc_info.value.args
-    assert "there is no bytecode at that address!" in error
 
 
 def test_abi_reverts(load_via_abi):