urlsplit manufactures hostnames because it strips off tabs before validating them

Bug report

Bug description:

import urllib.parse

# prints "abcxyz.test"
print(urllib.parse.urlsplit("http://abc\txyz.test/").netloc)

Current urlsplit is implemented according to this spec:

https://url.spec.whatwg.org/#concept-basic-url-parser

The spec does say in item 3 to strip tabs, but I believe there's a bug in the specification (perhaps they wanted to say leading/trailing whitespace) because the item 7 in host parsing says

If asciiDomain contains a forbidden domain code point, domain-invalid-code-point validation error, return failure.

, and tab is listed as a "forbidden domain code point". If tabs are stripped from the entire input before any other work is done, checking for tabs in host names wouldn't make much sense.

I created a bug in the specification project, so maybe they will provide some guidance later on.

https://github.com/whatwg/url/issues/829

CPython versions tested on:

3.10

Operating systems tested on:

Linux, Windows

urllib.parse.urlsplit のエントリポイントから開始し、埋め込まれたタブによって netloc がどのように変わるかを確認するため、issue の reproducer を実行します。仕様上の競合についての指針として、リンクされた WHATWG URL issue 829 を読みます。ホスト名内のタブが別のホスト名に暗黙的に変換されなければ完了です。