parseJSON errors on non-hex strings starting with 0x

[dyedm1]

Component

Forge, Anvil

Have you ensured that all of these are up to date?

• Foundry
• Foundryup

What version of Foundry are you on?

forge 0.2.0 (c8db1e4 2024-06-27T00:18:32.026850000Z)

What command(s) is the bug in?

No response

Operating System

Linux

Describe the bug

As specified here, the parser will attempt to cast any JSON strings beginning with 0x to a bytearray (or an address/bytes32 if the size matches). While this interpretation likely works well enough most of the time, there is also the possibility that a string that begins with 0x is either not intended to be interpreted as a hex value or prefixes only a portion of a string interpretable as hex (where the entire string is not).

As an example, suppose you wanted to represent the 0xBitcoin token in JSON. The following JSON:

{
"name": "0xBitcoin Token",
"symbol": "0xBTC",
"decimals": 18
}

would fail with an error message like Invalid character 'i' at position 1 if passed into vm.parseJson. Similarly, a string beginning with a valid hex substring (such as an address) like "0x834629f473876e5f0d3d9d269af3dabcb0d7d520-identifier-0" would also fail once the hyphen was hit: Invalid character '-' at position 41.

This is not ideal and can cause unexpected failures if the content of the strings in JSON is unsanitized. Ideally, the parser would fallback to a string upon failure to coerce a value into a bytearray/address/bytes32 instead of returning an error.

[mattsse]

do you have a solidity repro for this?

[dyedm1]

pragma solidity ^0.8.0;

import "forge-std/Test.sol";

contract A is Test {
    function test_hexprefixednonhexstring() public {
        vm.parseJson("{\"a\": \"0x834629f473876e5f0d3d9d269af3dabcb0d7d520-identifier-0\"}");
        vm.parseJson("{\"b\": \"0xBTC\"}");
    }
}