Bug 271718 – CSSOM selector text serialization misbehaves when there are more than 8192 tokens

• Status: NEW
• Component: CSS

[Qianlang Chen]

Created attachment 470609 [details]
Test case: Open to see instructions

If a CSS rule is something like
    a1, a2, a3, a4, ......., a8190, a8191, a8192, a8193 {
        color: blue;
    }

Where there are more than 8192 whitespace-separated tokens in the selector text, then that rule's `cssText` getter returns a serialized text that's missing some of the tokens, for instance something like
    a1, a2, a3, a4, ......., a8190, a8191 {
        color: blue;
    }

(To clarify, the ellipses are NOT literal and actually include all the aXXX tokens)

This behavior does not replicate on Firefox or Chrome. The specs (https://drafts.csswg.org/cssom/) does not seem to suggest there be any maximum limit of selector text length CSSOM should support.

See attached for a downloadable HTML test case.

[Qianlang Chen]

Created attachment 470610 [details]
Video demo: tokens start to disappear after having 8193 of them

[Radar WebKit Bug Importer]

<rdar://problem/125437578>

[Qianlang Chen]

This bug likely relates to https://webkit.org/b/229218 (Style rules declared after a rule whose selector has over 8192 components are not shown correctly)