Error with canonicalize a protocol getting called with an empty string

[crowlKats]

Given testdata

  {
    "pattern": [{ "pathname": "/foo/bar" }],
    "inputs": [{ "pathname": "/foo/bar" }],
    "expected_match": {
      "pathname": { "input": "/foo/bar", "groups": {} }
    }
  },

we are getting an error in the constructor at compile a component for protocol, as the call to canonicalize a protocol is happening with an empty string as argument. that call is happening in maybe add a part from the pending fixed value, which is getting called in add a part, which is called at https://wicg.github.io/urlpattern/#ref-for-add-a-part.
This does seem a bug with the spec since we re-checked our code regarding the steps involved and everything seems correct, though we might have overlooked something.

The steps defined for canonicalize a protocol can never succeed for an empty string input.

[wanderview]

Step 1 of "maybe add a part from the pending fixed value":

https://wicg.github.io/urlpattern/#maybe-add-a-part-from-the-pending-fixed-value

Has an early return for empty string. Is that not catching this case?

[wanderview]

However, I do see in the c++ implementation that I have empty string checks in all the encoding callback implementations. That's probably the most expedient fix here as well.

[wanderview]

To clarify, there are other places in "add a part" where we invoke the encoding callback without checking to see if the value is empty first or not. I can see in the c++ implementation that we do pass empty strings to the encoding callbacks.

[crowlKats]

Has an early return for empty string. Is that not catching this case?

it isn't

To clarify, there are other places in "add a part" where we invoke the encoding callback without checking to see if the value is empty first or not. I can see in the c++ implementation that we do pass empty strings to the encoding callbacks.

Oh I see, i guess that is most likely what the issue is