Event decode error

[aquiladev]

Ethers Version

5.4.7

Search Terms

No response

Describe the Problem

A deferred error occurs during event decoding
deferred error during ABI decoding triggered accessing property "uri"

Example:

Transaction: 0xcdfd34b37bc1c13eced1db6ade088d4971725c2428badaa06f6f9f23282a520a
LogIndex: 412
Argument: uri
Event data: 0x0000000000000000000000000000000000000000000000000000000000000020000000000000000000000000000000000000000000000000000000000000001cb38ff09f8d80e2888cf09f2e6f6e706f6c79676f6e2e63727970746f00000000

Code Snippet

No response

Contract ABI

['event NewURI (uint256 indexed tokenId, string uri)']

Errors

No response

Environment

node.js (v12 or newer)

Environment (Other)

No response

[ricmoo]

Yes, as you can see in the data, the first byte of the string is 0xb3 (i.e. (0b10110011)). If a UTF-8 byte begins with 0b10xxxxxx, it is expected to be a continuation byte, which means it must follow other bytes; since it is the first byte, that's obviously not true. :)

So, basically, they're invalid binary data at the beginning of that string. If you use the replace Utf8ErrorFunc to recover the string you can see a bit more:

> v = "0xb38ff09f8d80e2888cf09f2e6f6e706f6c79676f6e2e63727970746f";
> toUtf8String(v, utils.Utf8ErrorFuncs.replace);
"�🍀∌�.onpolygon.crypto"

Notice there are two replacement characters, so there were multiple UTF-8 faults in that string. This is why you get a deferred error, so you have an opportunity to debug or recover, as appropriate.

Hope that helps. :)

[bogdan]

@ricmoo can you make it an option of Event#decode or Interface#decodeEventLog? Otherwise, I believe it would require to copy a lot of code from ethers to make a universal decoder that supports utils.Utf8ErrorFuncs.replace .