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I wrote this Solidity function:

function getAssetSymbol(IERC20Metadata asset) internal view returns (string memory) {
    try asset.symbol() returns (string memory symbol) {
        return symbol;
    } catch {
        return "ERC20";
    }
}

And, while testing it, I realized that reverts are not caught when:

  • asset is an address that doesn't contain code
  • asset returns a bytes32 instead of string (e.g. the MKR token does this)

Why is that? I was expecting try/ catch to handle these reverts.

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try..catch doesn't catch the boundary exceptions, just the inner method call. Exactly that, what you have mentioned:

  • checks if address is not void
  • checks if extcodesize exists
  • --checks if method exists-- This will be caught.

Any fails at this steps cause the revert. After the method is executed:

  • checks if the return is as expected and can be decoded

A failure at this step also causes the revert.

Additional infos: try-catch


Sorry, initially I've written it reverts if the method does not exist. I was not sure about that and I was wrong, the call to an unexisting method will be caught. I think the method invocation is already at the inner contract level, as it executes a fallback method if any, otherwise reverts, which will be caught by the try..catch

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  • Sorry Paul, the nonexisting method call will be caught by the try..catch
    – tenbits
    May 24, 2023 at 12:40

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