fix: deserialize missing state mutability as non payable

crates/json-abi/src/item.rs

@@ -66,20 +66,23 @@ abi_items! {
         /// The input types of the constructor. May be empty.
         pub inputs: Vec<Param>,
         /// The state mutability of the constructor.
+        #[serde(default)]
         pub state_mutability: StateMutability,
     }
 
     /// A JSON ABI fallback function.
     #[derive(Copy)]
     pub struct Fallback: "fallback" {
         /// The state mutability of the fallback function.
+        #[serde(default)]
         pub state_mutability: StateMutability,
     }
 
     /// A JSON ABI receive function.
     #[derive(Copy)]
     pub struct Receive: "receive" {
         /// The state mutability of the receive function.
+        #[serde(default)]
         pub state_mutability: StateMutability,
     }
 
@@ -93,6 +96,9 @@ abi_items! {
         /// The output types of the function. May be empty.
         pub outputs: Vec<Param>,
         /// The state mutability of the function.
+        ///
+        /// By default this is [StateMutability::NonPayable] which is reflected in Solidity by not specifying a state mutability modifier at all. This field was introduced in 0.4.16: <https://github.com/ethereum/solidity/releases/tag/v0.4.16>
+        #[serde(default)]
         pub state_mutability: StateMutability,
     }
 

crates/json-abi/src/lib.rs

@@ -50,14 +50,22 @@ mod to_sol;
 pub(crate) mod utils;
 
 /// A JSON ABI function's state mutability.
-#[derive(Clone, Copy, Debug, PartialEq, Eq, PartialOrd, Ord, Hash, Serialize, Deserialize)]
+#[derive(
+    Clone, Copy, Debug, Default, PartialEq, Eq, PartialOrd, Ord, Hash, Serialize, Deserialize,
+)]
 #[serde(rename_all = "lowercase")]
 pub enum StateMutability {
     /// Pure functions promise not to read from or modify the state.
     Pure,
     /// View functions promise not to modify the state.
     View,
     /// Nonpayable functions promise not to receive Ether.
+    ///
+    /// This is the solidity default: <https://docs.soliditylang.org/en/latest/abi-spec.html#json>
+    ///
+    /// The state mutability nonpayable is reflected in Solidity by not specifying a state
+    /// mutability modifier at all.
+    #[default]
     NonPayable,
     /// Payable functions make no promises.
     Payable,

crates/json-abi/tests/abi/ZRXToken.json

@@ -0,0 +1 @@
+[{"constant":true,"inputs":[],"name":"name","outputs":[{"name":"","type":"string"}],"payable":false,"type":"function"},{"constant":false,"inputs":[{"name":"_spender","type":"address"},{"name":"_value","type":"uint256"}],"name":"approve","outputs":[{"name":"","type":"bool"}],"payable":false,"type":"function"},{"constant":true,"inputs":[],"name":"totalSupply","outputs":[{"name":"","type":"uint256"}],"payable":false,"type":"function"},{"constant":false,"inputs":[{"name":"_from","type":"address"},{"name":"_to","type":"address"},{"name":"_value","type":"uint256"}],"name":"transferFrom","outputs":[{"name":"","type":"bool"}],"payable":false,"type":"function"},{"constant":true,"inputs":[],"name":"decimals","outputs":[{"name":"","type":"uint8"}],"payable":false,"type":"function"},{"constant":true,"inputs":[{"name":"_owner","type":"address"}],"name":"balanceOf","outputs":[{"name":"","type":"uint256"}],"payable":false,"type":"function"},{"constant":true,"inputs":[],"name":"symbol","outputs":[{"name":"","type":"string"}],"payable":false,"type":"function"},{"constant":false,"inputs":[{"name":"_to","type":"address"},{"name":"_value","type":"uint256"}],"name":"transfer","outputs":[{"name":"","type":"bool"}],"payable":false,"type":"function"},{"constant":true,"inputs":[{"name":"_owner","type":"address"},{"name":"_spender","type":"address"}],"name":"allowance","outputs":[{"name":"","type":"uint256"}],"payable":false,"type":"function"},{"inputs":[],"payable":false,"type":"constructor"},{"anonymous":false,"inputs":[{"indexed":true,"name":"_from","type":"address"},{"indexed":true,"name":"_to","type":"address"},{"indexed":false,"name":"_value","type":"uint256"}],"name":"Transfer","type":"event"},{"anonymous":false,"inputs":[{"indexed":true,"name":"_owner","type":"address"},{"indexed":true,"name":"_spender","type":"address"},{"indexed":false,"name":"_value","type":"uint256"}],"name":"Approval","type":"event"}]

crates/json-abi/tests/abi/ZRXToken.sol

@@ -0,0 +1,14 @@
+interface ZRXToken {
+    event Approval(address indexed _owner, address indexed _spender, uint256 _value);
+    event Transfer(address indexed _from, address indexed _to, uint256 _value);
+
+    function allowance(address _owner, address _spender) external returns (uint256);
+    function approve(address _spender, uint256 _value) external returns (bool);
+    function balanceOf(address _owner) external returns (uint256);
+    function decimals() external returns (uint8);
+    function name() external returns (string memory);
+    function symbol() external returns (string memory);
+    function totalSupply() external returns (uint256);
+    function transfer(address _to, uint256 _value) external returns (bool);
+    function transferFrom(address _from, address _to, uint256 _value) external returns (bool);
+}

crates/sol-types/tests/macros/sol/json.rs

@@ -179,3 +179,14 @@ fn junkyard() {
     // https://etherscan.io/address/0x2e4b0f20bdb1caa0886c531256efdaab925dbe72
     sol!(Junkyard, "../json-abi/tests/abi/Junkyard.json");
 }
+
+// Handle missing state mutability in JSON ABI
+// https://github.com/alloy-rs/core/issues/485
+#[test]
+fn zrx_token() {
+    // https://etherscan.io/address/0xe41d2489571d322189246dafa5ebde1f4699f498#code
+    sol!(ZRXToken, "../json-abi/tests/abi/ZRXToken.json");
+
+    let _ = ZRXToken::approveCall { _spender: Address::ZERO, _value: U256::ZERO };
+    assert_eq!(ZRXToken::approveCall::SIGNATURE, "approve(address,uint256)");
+}