Allow null-ish properties in TypedData domains to imply unspecified

[frangio]

Ethers Version

5.7.2

Search Terms

hashDomain

Describe the Problem

hashDomain throws an error when the argument is a domain object with name: undefined. Note that it correctly processes a domain object with no name at all, because it's an optional field. A name field with an undefined value should be treated the same way, if only because TypeScript can't distinguish a missing field from an undefined-valued field.

This probably applies to all the other optional domain fields as well, though I haven't tested.

Code Snippet

utils._TypedDataEncoder.hashDomain({ name: undefined })

Contract ABI

No response

Errors

Uncaught TypeError: Cannot read properties of undefined (reading 'length')
    at toUtf8Bytes (node_modules/@ethersproject/strings/lib/utf8.js:179:29)
    at id (node_modules/@ethersproject/hash/lib/id.js:7:65)
    at node_modules/@ethersproject/hash/lib/typed-data.js:161:32
    at node_modules/@ethersproject/hash/lib/typed-data.js:293:56

Environment

No response

Environment (Other)

No response

[ricmoo]

I tend to agree that undefined should be treated as not specified. I would also expand this to null too.

But one quick note is that Typescript can distinguish a missing field (i.e. !("foo" in bar)) and an undefined value (i.e. "foo" in bar && bar.foo === undefined).

Moving this to an enhancement, which will probably be included in v6. :)

[frangio]

But one quick note is that Typescript can distinguish a missing field (i.e. !("foo" in bar)) and an undefined value (i.e. "foo" in bar && bar.foo === undefined).

I meant at the type level. A function that accepts an argument of type { foo?: string } will accept both { } and { foo: undefined }. Not so with null, which is why I wasn't including it.

The concrete example here is that the expression hashDomain({ name: undefined }) is well typed, yet it results in a runtime error because undefined is not properly handled. I consider this a bug rather than an enhancement.

[ricmoo]

Added in v6. I'll leave open to remind me for the next minor bump of v5.