Bug 11387 – CSS3: :empty selector is applied to all elements (Acid3 bug)

• Component: CSS
• Status: RESOLVED FIXED

[Niels Leenheer (HTML5test)]

Current behavoir:
The :empty selector matches every element.

Reason:
The reason for this is that every time a new element is added to the DOM, it is checked to see if it matches one of the CSS selectors. Because the DOM is build one element at a time, every element is at least for a brief moment empty. 

Proper behavoir:
The :empty selector should only match elements that are *really* empty. Once an element is no longer empty it should no longer match this selector.

[Eric Seidel (no email)]

I think Test 37 in Acid3 is hitting this bug.

[Robert Blaut]

Created attachment 18798 [details]
test case

[Robert Blaut]

Currently it's a test 38 in Acid3:

    function () {
      // test 38: :empty
      selectorTest(function (doc, add, expect) {
        var empty = add(":empty");
        var p = doc.createElement('p');
        doc.body.appendChild(p);
        expect(p, empty, "empty element didn't match :empty");
        var span = doc.createElement('span');
        p.appendChild(span);
        expect(p, 0, "removing all children didn't make the element match :empty");
        p.removeChild(span);
        p.appendChild(doc.createComment("c"));
        p.appendChild(doc.createTextNode("a"));
        expect(p, 0, "element with no child element nodes didn't match :empty");
      });
      return 3;
    },

[Ian 'Hixie' Hickson]

Wow, that test had errors. Fixed. Doesn't affect this bug, though.

[Dave Hyatt]

Created attachment 18831 [details]
Patch that implements dynamic :empty

[Oliver Hunt]

Comment on attachment 18831 [details]
Patch that implements dynamic :empty

The formatting change in CSSStyleSelector::locateSharedStyleseems unnecessary.

This looks good to me, but given mitz spotted the issue with comment nodes breaking the hasChildNodes() == style->emptyState() check and i didn't, i figure i'll leave this to him.

Comment on attachment 18831 [details]
Patch that implements dynamic :empty

r=me with the condition changed to (!style->emptyState() || hasChildNodes()).

[Dave Hyatt]

Created attachment 18840 [details]
Revised patch with refinements from Acid3 testing.

[Oliver Hunt]

Comment on attachment 18840 [details]
Revised patch with refinements from Acid3 testing.

r=me

[Dave Hyatt]

Fixed in r29918.