dnsEncode() throws too early

[adraffy]

Ethers Version

6.10

Search Terms

dnsEncode, ccip, ensip-10, wrapper

Describe the Problem

dnsEncode() throws on >63 but should throw for >255. This causes longer names to be unreachable via CCIP and can't decode NameWrapper names() function.

Possibly the function needs renamed if this was used for other purposes.

Example:

// throws "invalid DNS encoded entry; length exceeds 63 bytes"
ethers.dnsEncode('a'.repeat(64)); 

Suggested implementation:

function dnsEncode(name: string): string 
  const MAX_LABEL = 255;
  let v = ensNameSplit(name).map(u => {
      if (u.length > MAX_LABEL) throw new Error(`label too long: ${u.length} > ${MAX_LABEL}`);
      return u;
  });
  v.push(0);
  return hexlify(v);
}

You can also massively simplify ensNameSplit():

function ensNameSplit(name: string): Array<Uint8Array> {
    const norm = ensNormalize(name); // empty string or all labels nonempty
    return norm ? norm.split('.').map(toUtf8Bytes) : [];
}

Code Snippet

No response

Contract ABI

No response

Errors

invalid DNS encoded entry; length exceeds 63 bytes

Environment

node.js (v12 or newer)

Environment (Other)

No response

[ricmoo]

DNS labels are restricted to a length of 63 (see RFC-1035.

Here is a short article by Microsoft on some of the nuances too. :)

[ricmoo]

Just to keep everyone informed, we've had discussions with ENS and have concluded this is a-ok. :)

...the limit should be 255. Labels that are longer than 63 characters won't be valid in DNS integrations, but that's fine. ~Nick (via Twitter)

In the next minor bump, I'll make the following change:

// current; 6.10
function dnsEncode(name: string): string;

// next minor; 6.11
function dnsEncode(name: string, maxLength = 63): string;

This will ensure the function continues working for others that may be using it using its current defaults, but when used internally by the wildcard resolution logic, it can expand the label width.

Can you also work on updating the ENSIP, @adraffy?

[adraffy]

Can you also work on updating the ENSIP, @adraffy?

Awesome. Yeah, I can submit that.

[ricmoo]

This has been address in v6.11.1. Try it out and let me know if you have any more issues.

Thanks! :)