Inherited properties from Object.prototype break checkType in ParamType

[zZoMROT]

Ethers Version

6.13.4

Search Terms

utils, properties, defineProperties, ParamType, checkType, keys

Describe the Problem

Description:

If a developer extends Object.prototype in their project by adding a custom function, this property gets copied into the ParamType object during its creation. This results in breaking the checkType method, as it attempts to process the inherited property as part of the expected data.

Proposed solution:

Add a filter using Object.prototype.hasOwnProperty to ensure only the object's own properties are processed when creating ParamType or invoking checkType. This will prevent inherited properties from being mistakenly copied.

Additional information:

In version 5, the similar issue also causes an error during RPC requests:

Error: could not detect network (event="noNetwork", code=NETWORK_ERROR, version=providers/5.7.0)

This occurs because the chainId cannot be retrieved due to an incorrect header object that includes a custom prototype property. Fixing the header iteration logic as described above will also resolve this issue. It can be fixed by

• replacing number 1:

  for (var key of [...Object.getOwnPropertyNames(connection.headers), ...Object.getOwnPropertySymbols(connection.headers)]) {
  

  instead of the code at this line.
• replacing number 2:

  Object.getOwnPropertyNames(object).forEach(key => { 
      result[key] = (object)[key]; 
  });
  Object.getOwnPropertySymbols(object).forEach(symbol => { 
      result[symbol] = (object)[symbol]; 
  });
  

  instead of the code at this line

Code Snippet

Object.prototype.customMethod = function () { return "custom"; };

const yourInfuraKey = process.env.INFURA_API_KEY || 'add your key here';
const provider = new ethers.JsonRpcProvider(`https://mainnet.infura.io/v3/${yourInfuraKey}`);

const abi = [{
   "inputs": [],
   "name": "decimals",
   "outputs": [
      {
         "internalType": "uint256",
         "name": "value",
         "type": "uint256"
      }
   ],
   "stateMutability": "view",
   "type": "function"
}];

const constractAddress = '0xa0b86991c6218b36c1d19d4a2e9eb0ce3606eb48';
const usdcToken = new ethers.Contract(constractAddress, abi, provider);
await usdcToken.decimals();

### Contract ABI

_No response_

### Errors

```shell
TypeError: type.split is not a function

Environment

No response

Environment (Other)

No response