IPv4 number parser on "0x0a"

[nlevitt]

https://url.spec.whatwg.org/#ipv4-number-parser

I think there's a bug in the spec here.

input="0x0a"

1. Let R be 10.
   R = 10
2. If input contains at least two code points and the first two code points are either "0x" or "0X", run these substeps:
   1. Set syntaxViolationFlag.
   2. Remove the first two code points from input.
      input = "0a"
   3. Set R to 16.
      R = 16
3. If input is the empty string, return zero.
4. Otherwise, if input contains at least two code points and the first code point is "0", run these substeps:
   we follow this code path
   1. Set syntaxViolationFlag.
   2. Remove the first code point from input.
      input = "a"
   3. Set R to 8.
      R = 8
5. If input contains a code point that is not a radix-R digit, and return failure.
   return failure
6. Return the mathematical integer value that is represented by input in radix-R notation, using ASCII hex digits for digits with values 0 through 15.

[nlevitt]

Ah and I should mention
https://github.com/w3c/web-platform-tests/blob/master/url/urltestdata.json#L2212

    "input": "http://192.0x00A80001",
    "href": "http://192.168.0.1/",

[nlevitt]

Swapping steps 3 and 4 fixes the problem.

[annevk]

Why did you mention the test?

[annevk]

In any event, created a PR to fix this. Would appreciate your review.

[nlevitt]

I mentioned the test because it has an ipv4 number that starts with "0x0" and it doesn't say the result should be failure, i.e. shows that this indeed a bug, assuming the test is correct.

[nlevitt]

Pull request looks good to me.