Difficulty: Entry ⭐

Q02EventsAndErrors exposes three intentionally-failing functions, each reverting with a different ABI-encoded error kind. You observe each revert via your wallet / web UI and submit its 4-byte selector back to the contract.

Make Q02EventsAndErrors.isSolved(yourAddress) return true by submitting all three selectors:

function failWithRequire(uint256 v) external pure;                   // reverts on v == 0
function failWithAssert(bool cond) external pure;                    // reverts on cond == false
function failWithCustomError(uint256 available, uint256 required)    // reverts on available < required
    external pure;

function reportErrorSelector(bytes4 selector) external;              // submit the string-revert selector
function reportPanicSelector(bytes4 selector) external;              // submit the panic selector
function reportCustomSelector(bytes4 selector) external;             // submit InsufficientBalance.selector

function isSolved(address user) external view returns (bool);

• Three intentionally failing functions and three selector-reporting functions.
• Each revert flavor is a different ABI encoding, so the revert payload itself is the clue.

• Observe the first 4 bytes of each revert payload and map them back to the matching reporter.
• One error is the standard require string form, one is the assert/panic form, and one is a custom error.
• You can derive the custom selector from the error signature if you prefer not to inspect the revert data.

• You only need to prove you recognized each revert kind once.
• Keep the solution scoped to your own address.

• The three revert encodings in EVM:
  • Error(string) — used by require(cond, "msg") and revert("msg").
  • Panic(uint256) — used by assert, divide-by-zero, array-out-of-bounds, etc.
  • Custom errors — selector = bytes4(keccak256("Name(types...)")).
• The 4-byte selector + ABI-encoded args layout is identical to a function call, which is what enables generic try / catch (bytes memory) decoding.