1419299 - Fix failure WPT test for document.write() on a data document in custom-elements/parser/parser-uses-registry-of-owner-document.html

Status: RESOLVED FIXED

(Core :: DOM: Core & HTML, enhancement, P3)

Description

[John Dai[:jdai]]

We got test failure at parser-uses-registry-of-owner-document.html[1][2][3]

[1] https://searchfox.org/mozilla-central/rev/919dce54f43356c22d6ff6b81c07ef412b1bf933/testing/web-platform/tests/custom-elements/parser/parser-uses-registry-of-owner-document.html
[2] https://searchfox.org/mozilla-central/rev/919dce54f43356c22d6ff6b81c07ef412b1bf933/testing/web-platform/meta/custom-elements/parser/parser-uses-registry-of-owner-document.html.ini
[3] http://web-platform.test:8000/custom-elements/parser/parser-uses-registry-of-owner-document.html

Comment 1

[John Dai[:jdai]]

Update [3] link: http://w3c-test.org/custom-elements/parser/parser-uses-registry-of-owner-document.html

Comment 2

[Edgar Chen [:edgar] (PTO until 02/09)]

Per step 3 of https://html.spec.whatwg.org/multipage/custom-elements.html#look-up-a-custom-element-definition, if the document is a data document (e.g. the one created via createDocument()), the document doesn't have an associated browsing context ( https://html.spec.whatwg.org/multipage/browsers.html#concept-document-bc). And nsContentUtils::LookupCustomElementDefinition() should return nullptr for this case.

Comment 3

[Edgar Chen [:edgar] (PTO until 02/09)]

(In reply to Edgar Chen [:edgar] from comment #2)
> And nsContentUtils::LookupCustomElementDefinition() should return nullptr
> for this case.
We do return nullptr for such case.

The test failure is because of the incorrectness in test itself.
The test is something like,

```
customElements.define("x-foo", class extends HTMLElement {});

var doc = document.implementation.createHTMLDocument();
doc.open();
doc.write('<x-foo></x-foo>');
doc.close();

var foo = doc.querySelector('x-foo');
assert_true(foo instanceof HTMLElement);
assert_false(foo instanceof MyCustomElement);
```

From the spec at step 3 of https://html.spec.whatwg.org/#document-write-steps: "If document is not an active document, then return", so an write() call on a data document should do nothing. And the `foo` should be null in this case. There is a discussion about it, see https://github.com/whatwg/html/issues/2827.

Comment 4

[Edgar Chen [:edgar] (PTO until 02/09)]

File https://github.com/w3c/web-platform-tests/issues/8530.

Comment 5

[Edgar Chen [:edgar] (PTO until 02/09)]

Fixed and merged in upstream; https://github.com/w3c/web-platform-tests/pull/8537.