Support partially named method arguments

Author: fjarri

docs/changelog.rst

@@ -9,9 +9,11 @@ Added
 ^^^^^
 
 - Support for contract errors with anonymous fields. (PR_90_)
+- Support for partially named method arguments. (PR_91_)
 
 
 .. _PR_90: https://github.com/fjarri-eth/pons/pull/90
+.. _PR_91: https://github.com/fjarri-eth/pons/pull/91
 
 
 0.10.0 (2025-10-19)

pons/_abi_types.py

@@ -512,13 +512,13 @@ def dispatch_types(abi_entry: ABI_JSON) -> list[Type] | dict[str, Type]:
 
     names = [entry["name"] for entry in abi_entry_typed]
 
-    # Unnamed arguments; treat as positional arguments
-    if names and all(not name for name in names):
+    # In Solidity, it is possible to have have an argument list like `(address x, uint256)`
+    # (that is, only some of the arguments are unnamed).
+    # This cannot be mapped to Python function signatures,
+    # so we have to treat this as if all the arguments were unnamed.
+    if names and any(not name for name in names):
         return [dispatch_type(entry) for entry in abi_entry_typed]
 
-    if any(not name for name in names):
-        raise ValueError("Arguments must be either all named or all unnamed")
-
     # Since we are returning a dictionary, need to be sure we don't silently merge entries
     if len(names) != len(set(names)):
         raise ValueError("All ABI entries must have distinct names")

tests/test_abi_types.py

@@ -256,8 +256,11 @@ def test_dispatch_types() -> None:
     # For an empty argument list we choose to resolve it as an empty dictionary, for certainty.
     assert dispatch_types([]) == {}
 
-    with pytest.raises(ValueError, match="Arguments must be either all named or all unnamed"):
-        dispatch_types([dict(name="foo", type="uint8"), dict(name="", type="uint16[2]")])
+    # Partially named arguments
+    assert dispatch_types([dict(name="x", type="uint8"), dict(name="", type="uint16[2]")]) == [
+        abi.uint(8),
+        abi.uint(16)[2],
+    ]
 
     with pytest.raises(ValueError, match="All ABI entries must have distinct names"):
         dispatch_types([dict(name="foo", type="uint8"), dict(name="foo", type="uint16[2]")])