750917 - [quirks mode] CSS text-decoration:underline on a block and vertical-align:top lead to a line above the text in quirks mode

Status: NEW

(Core :: Layout, defect)

Description

[Daniel Smallwood]

Attachment: Reproduces the problem with minimal html+css

when text-decoration:underline is applied to an element twice, and vertical-align is also defined, the underline renders twice. vertical-align dictates whether the line appears above the text (looking like an overline) or below the other underline.

Comment 1

[Alice0775 White]

Works(under-line appears):
http://hg.mozilla.org/mozilla-central/rev/be4b064f1159
Mozilla/5.0 (Windows NT 6.1; WOW64; rv:8.0a1) Gecko/20110804 Firefox/8.0a1 ID:20110804030732
Fails(over-line only appears):
http://hg.mozilla.org/mozilla-central/rev/5d742d2e4304
Mozilla/5.0 (Windows NT 6.1; WOW64; rv:8.0a1) Gecko/20110803 Firefox/8.0a1 ID:20110804022245
Pushlog:
http://hg.mozilla.org/mozilla-central/pushloghtml?fromchange=be4b064f1159&tochange=5d742d2e4304

Suspected: Bug 403524


Fails(over-line only appears):
http://hg.mozilla.org/mozilla-central/rev/42f7ed136034
Mozilla/5.0 (Windows NT 6.1; WOW64; rv:8.0a1) Gecko/20110810 Firefox/8.0a1 ID:20110811033415

Fails(over-line and under-line appear both)
http://hg.mozilla.org/mozilla-central/rev/10915aa17365
Mozilla/5.0 (Windows NT 6.1; WOW64; rv:8.0a1) Gecko/20110811 Firefox/8.0a1 ID:20110811041229
Pushlog:
http://hg.mozilla.org/mozilla-central/pushloghtml?fromchange=42f7ed136034&tochange=10915aa17365

Suspected: Bug 676538

Comment 2

[Boris Zbarsky [:bzbarsky]]

This testcase is in quirks mode.  I believe the behavior is in fact correct given the quirks inline box model, as far as it goes...  And of course in standards mode the behavior disappears completely, as expected.

Comment 3

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

This seems pretty similar to bug 714519; worth considering why the fix to that bug didn't fix this case.

Comment 4

[Harlan Lieberman-Berg]

Confirmed this issue occurs on the latest trunk in Linux as well.

Comment 5

[Chris Walsh]

Issue still exists on version 22 and 23 of x86 Firefox.
Also, the issue does occur in standards mode and is not quirks specific.

Comment 6

[Chris Walsh]

Attachment: Fault showing in Standards Compliance mode

The problem on occurs when the following is true:
1) text-decoration: underline is applied to :hover and none is applied to non-pseudo
2) vertical-align is inside the text-decoration (e.g. span inside a)
3) parent elemetn (a) is of display block type

Comment 7

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

I don't have time to look closely right now, but that might be a sign that it's actually a different bug.

Comment 8

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

comment 6 is bug 727125 and *not* this bug.

(It's worth considering whether this bug is the same as bug 712875.)

Comment 9

[Daniel Holbert [:dholbert]]

Attachment: testcase 2 (more thorough)

Here's a test that demonstrates this with underline, overline, and line-through being set on the parent of spans with various vertical-align values.

The "[vertical-align:]baseline" examples render correctly, as you'd expect, but the rest are broken. In particular, the overline/vertical-align:top example produces a line that's floating ~1em above the top of the div.

Comment 10

[Daniel Holbert [:dholbert]]

Attachment: testcase 3 (standards mode)

Here's the same testcase, now in standards mode. This makes it render correctly, AFAICT. (underlines/overlines all in the right place)

Comment 11

[Daniel Holbert [:dholbert]]

(In reply to Boris Zbarsky [:bz] from comment #2)
> This testcase is in quirks mode.  I believe the behavior [on orig. testcase] is in fact correct
> given the quirks inline box model, as far as it goes...

bz, do you know if the quirks inline box model is documented anywhere? And does our rendering of testcase 2 (attachment 8433553 [details]) make sense to you, in that model?

Comment 12

[Boris Zbarsky [:bzbarsky]]

I don't know, and I don't know.  Maybe dbaron does?

Comment 13

[Mats Palmgren (inactive)]

Attachment: testcase 4, using vertical-align:bottom (quirks mode)

This may or may not be the same underlying bug.  Just attaching it here so
it's not lost.