329763 - border-collapse does not inherit into table due to rule in UA style sheet

Status: NEW

(Core :: CSS Parsing and Computation, defect)

Description

[Eira Monstad]

According to CSS2.1, border-collapse should inherit. This does not happen in Firefox.

Comment 1

[Eira Monstad]

Attachment: Testcase

Comment 2

[Eli Friedman]

Attachment: Patch

This might be a WONTFIX, although I doubt this patch will have any side effects.

Comment 3

[David Baron :dbaron: (⌚️UTC-5, no longer working on Mozilla)]

For what it's worth, this dates back to when the CSS spec made 'border-collapse: collapse' the initial value and we had to specify table { border-collapse: separate } in the UA style sheet.

How do other browsers behave?  I can guess it does inherit in Opera...

Comment 4

[Eli Friedman]

(In reply to comment #3)
> How do other browsers behave?  I can guess it does inherit in Opera...

Windows browsers:
It does inherit in Opera, it doesn't inherit in Safari, and IE doesn't support border-collapse.

Comment 5

[David Baron :dbaron: (⌚️UTC-5, no longer working on Mozilla)]

IE/Windows has supported border-collapse for ages.

Comment 6

[Eli Friedman]

Oh, right.  Brain fart.  But I don't really understand why IE is rendering this testcase so much differently from other browsers...

Comment 7

[David Baron :dbaron: (⌚️UTC-5, no longer working on Mozilla)]

Not supporting border-style: hidden, perhaps?

So what do IE/Windows and Safari do?  Do they have default styles, or do they treat border-collapse as non-inherited?  You can distinguish using testcases with anonymous table objects using explicit 'inherit', and checking computed styles on rows, cells, and contents of cells.  (I suspect only the latter works in IE.)

Comment 8

[Eli Friedman]

Looks like Safari has a similar style rule to what we have.  It does not inherit in Internet Explorer.

Comment 9

[David Baron :dbaron: (⌚️UTC-5, no longer working on Mozilla)]

Comment on attachment 270494 [details] [diff] [review]
Patch

I honestly don't understand why border-collapse is an inherited property at all, but given than Safari has this in the UA style sheet as well, I don't see why we shouldn't leave it too.

Comment 10

[Eli Friedman]

Does that make this WONTFIX?

Comment 11

[David Baron :dbaron: (⌚️UTC-5, no longer working on Mozilla)]

How solid is your info on what IE/Windows does?

Comment 12

[Eli Friedman]

Pretty solid; I used currentStyle to check on a couple of divs, which shouldn't have the style set by default.  (I suppose it's possible there's a rule like 
"* {border-collapse: separate}" in IE's UA stylesheet, but it would be impossible to tell the difference since IE doesn't support inherit.)

Comment 13

[J. Raaijmakers]

I checked the state of some browsers today against this bug. My testcase resides at http://gmta.nl/bugs/tablecssbug.html. The results:

IE6: does not inherit
IE8: inherits
Firefox 3.5: does not inherit
Opera 9: inherits
Safari 4 (win32): does not inherit
Google Chrome 2: does not inherit

It seems that IE8 and Opera 9 adhere closer to border-collapse as defined by the W3C than Safari, Firefox and Chrome. I would very much like to see Firefox obeying the inheriting rule for this property.