1150991 - createComment lets you create comments containing '-->' which don't round-trip

Status: RESOLVED INVALID

(Core :: DOM: Core & HTML, defect)

Description

[Roan Kattouw]

User Agent: Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:36.0) Gecko/20100101 Firefox/36.0
Build ID: 20150321175551

Steps to reproduce:

> div = document.createElement( 'div' );
> div.appendChild( document.createComment( 'Foo-->bar' ) );
> div.childNodes;
NodeList [ <!-- Foo-->bar --> ]
> div.innerHTML;
"<!--Foo-->bar-->"
> div.innerHTML = div.innerHTML;
> div.childNodes
NodeList [ <!-- Foo -->, #text "bar-->" ]


Actual results:

I was allowed to create a comment that contained '-->' , and this triggered a round-trip failure.


Expected results:

I possibly should not be allowed to create a comment containing '-->' (there used to be an exception thrown for '--' but that was removed per spec, see https://bugzilla.mozilla.org/show_bug.cgi?id=412257 ). I definitely should not be able to create DOMs that don't round-trip.

Comment 1

[Roan Kattouw]

This seems to be a bug in the spec rather than in Firefox specifically: the same behavior happens in Chrome 41 and IE 11.

Comment 2

[Roan Kattouw]

Corresponding bug report in Chrome: https://code.google.com/p/chromium/issues/detail?id=473767

Comment 3

[Nickolay_Ponomarev]

Thanks for the report! This is essentially the same as bug 974212, but the description in that bug is not as clear as in this one, for me to be completely sure.

Comment 4

[Boris Zbarsky [:bzbarsky]]

> I definitely should not be able to create DOMs that don't round-trip.

That's completely infeasible in HTML.  For example, you can append kids to an <img> element, which won't round-trip when serialized and parsed as HTML (not XHTML).

In any case, we're just following the spec here.  If you think the spec should change, you should probably raise a spec issue, not bug reports on browsers.