Relative / Descendent Selectors #252
Description
The documentation suggests that a selector when applied to an ElementRef will match against children/descendents of the element. This does not seem to be the case unless the css rule is prefixed by :scope. All selectors not prefixed by :scope seem to match against the root element, regardless of which ElementRef is used for matching.
The specific documentation for ElementRef::select says:
Returns an iterator over descendent elements matching a selector.
The following test case reproduces the behavior.
#[test]
fn test_relative_selector() {
let raw_html = r#"
<html>
<body>
<article>
<div>
<h1>select me</h1>
</div>
</article>
</body>
</html>
"#;
let doc = Html::parse_document(raw_html);
// this works
let selector = Selector::parse("body > article > div > h1").unwrap();
let el = doc.root_element().select(&selector).next();
assert!(el.is_some());
let article = doc.root_element()
.select(&Selector::parse("body > article").unwrap())
.next()
.unwrap();
// this works too. using :scope to indicate selector relative to the article element
let scoped_selector = Selector::parse(":scope > div > h1").unwrap();
let el = article.select(&scoped_selector).next();
assert!(el.is_some());
// this should not match relative to the article element, but it does match.
let scoped_selector = Selector::parse("body > article > div > h1").unwrap();
let el = article.select(&scoped_selector).next();
assert!(el.is_none());
}