Cannot keys or values from json object using stdJson.readStringArray

[lnist]

Component

Forge

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

• [X] Foundry
• [X] Foundryup

What version of Foundry are you on?

forge 0.2.0 (8f246e0 2023-04-28T00:03:59.802167368Z)

What command(s) is the bug in?

forge test

Operating System

Linux

Describe the bug

Due to https://github.com/foundry-rs/foundry/pull/4833 we tried to update lib/forge-std from 4a79aca83f8075f8b1b4fe9153945fef08375630 to b971f66b8416e3b09f240f6ee7230ad3bdb13c19 in order to set the number of expected calls.

However, that breaks our usage of readStringArray . We try to read the methodIdentifiers from the ABI output in the "out" files. We have previously been able to use code similar to the following:

// SPDX-License-Identifier:	AGPL-3.0
pragma solidity ^0.8.17;

import {stdJson} from "forge-std/StdJson.sol";
import {Test, console2} from "forge-std/Test.sol";

contract JsonTest is Test {
  function test_readStringArray() public view {
    string memory json = "{ \"abi\": [ ], \"methodIdentifiers\": { \"function1()\": \"abcdabcd\", \"function2()\": \"def0def0\" } } ";
    string[] memory methodIdentifiers = stdJson.readStringArray(json, ".methodIdentifiers[*]~");
    bytes[] memory selectors = new bytes[](methodIdentifiers.length);
    for (uint i = 0; i < methodIdentifiers.length; i++) {
      selectors[i] = vm.parseBytes(methodIdentifiers[i]);
    }
    console2.log(vm.toString(selectors[0]));
    console2.log(vm.toString(selectors[1]));
  }
}

Which outputs the following on the old version of the lib

[PASS] test_readStringArray() (gas: 15952)
Logs:
  0xabcdabcd
  0xdef0def0

But with the updated lib/forge-std we get:

 [FAIL. Reason: EvmError: Revert] test_readStringArray() (gas: 4281)
Traces:
  [4281] JsonTest::test_readStringArray() 
    ├─ [0] VM::parseJsonStringArray({ "abi": [ ], "methodIdentifiers": { "function1()": "abcdabcd", "function2()": "def0def0" } } , .methodIdentifiers[*]~) 
    │   └─ ← 0x000000000000000000000000000000000000000000000000000000000000002000000000000000000000000000000000000000000000000000000000000000086162636461626364000000000000000000000000000000000000000000000000
    └─ ← "EvmError: Revert"

Note, the ~ at the end of .methodIdentifiers[*]~ should actually make it output the keys and not the values, but that is a separate and not important issue for us. Without it it still does not work.

Looking at https://github.com/foundry-rs/foundry/blob/8f246e07c89129b6effa89f0d71c4ac67758a155/testdata/cheats/Json.t.sol it seems reading all the keys or values of objects is not in the test suite, so could it be broken or are we using it wrong?