292295 - margin collapse fails if parent uses property clear

Status: VERIFIED FIXED

(Core :: Layout: Block and Inline, defect)

Description

[Michael Ward]

User-Agent:       Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.8b2) Gecko/20050428 Firefox/1.0+
Build Identifier: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.8b2) Gecko/20050428 Firefox/1.0+

Part of bug 289480 hopefully this is a reduced test case

Reproducible: Always

Steps to Reproduce:
1. Open the testcase (will attach next)
2. 
3.

Actual Results:  
Notice whitespace between the green and black

Expected Results:  
No whitespace

Comment 1

[Michael Ward]

Attachment: (Hopefully) demonstraits bad behavior

According to the Acid 2 guide, the margins for .empty, .empty div, .smile, and
.smile div should all collapse. After this, .smile is moved down to clear the
floating nose. The .smile div doesn't get collapsed by us however

Comment 2

[Doug Wright]

assigning bug per bug 289480 comment 30

Comment 3

[Robert O'Callahan (:roc) (email my personal email if necessary)]

OK. I agree there's a bug ... it shouldn't be hard to fix.

Comment 4

[Taral]

*** Bug 296648 has been marked as a duplicate of this bug. ***

Comment 5

[RSpliet]

Okay, I tested this rendering bug in both 1.0.4 and deer park alpha 1 (1.1a)...
and here's the result:
http://img260.echo.cx/img260/7892/schermafdruk65jk.png

It seems like this bug was fixed or not present in 1.0.4, but is still available
in 1.1a. Is this correct, does deer park contain an older version (or a
different branch) of gecko? Or am I losing my marbles? :)

Comment 6

[Michael Ward]

Interesting, 1.0.4 does not render the gap here, but does in bug 296648 and in
acid 2. 1.1a fails all three...

Comment 7

[Robert O'Callahan (:roc) (email my personal email if necessary)]

Attachment: fix

I think this is just a silly error. Blocks with clearance are not necessarily
top-margin roots; in fact, the parent block does compute and manage the top
margins of a child with clearance and and any descendants whose margins
collapse with the top margin.

Comment 8

[David Baron :dbaron: (⌚️UTC-4, no longer working on Mozilla)]

Comment on attachment 186279 [details] [diff] [review]
fix

Looks right, r+sr=dbaron.  Did you run Hixie's tests?

Comment 9

[Robert O'Callahan (:roc) (email my personal email if necessary)]

I reran Hixie's tests at
http://www.hixie.ch/tests/adhoc/css/box/block/margin-collapse. With this patch,
we pass all but
http://www.hixie.ch/tests/adhoc/css/box/block/margin-collapse/024.html
http://www.hixie.ch/tests/adhoc/css/box/block/margin-collapse/044.html
http://www.hixie.ch/tests/adhoc/css/box/block/margin-collapse/049.html
http://www.hixie.ch/tests/adhoc/css/box/block/margin-collapse/057.html
http://www.hixie.ch/tests/adhoc/css/box/block/margin-collapse/061.html
(Red lines show up in a few others due to rounding issues.) We already fail
those tests on trunk so I think this patch is good.

Comment 10

[Robert O'Callahan (:roc) (email my personal email if necessary)]

Comment on attachment 186279 [details] [diff] [review]
fix

layout fix that probably isn't 1.8-worthy except for the fact that it fixes an
issue in the Acid2 test.

Comment 11

[Robert O'Callahan (:roc) (email my personal email if necessary)]

checked in

Comment 12

[Marek Stępień [:marcoos, inactive]]

Verified.