245926 - whitespace in inline elements parsed incorrectly & coalesced badly

Status: RESOLVED WORKSFORME

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

Description

[Bryan Mills]

User-Agent:       Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.4) Gecko/20030624
Build Identifier: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.4) Gecko/20030624

Leading and trailing whitespace in inline elements is incorrect in some
instances and counterintuitive in some others.

Section B.3.1 in the HTML 4.01 spec says that line breaks immediately following
start tags and immediate preceding end tags must be ignored.  However, they are
not correctly ignored.  (See example 1 -- a should be identical to b.)

Whitespace should tend to coalesce to the outside, not to the left.  That is,
when coalescing trailing whitespace in a link and whitespace after the link's
closing tag, the whitespace after the closing tag should always be kept. 
Otherwise, two discrete links could *unintentionally* share a single underline
(see example 2).

example 3 is somewhat a matter of personal opinion, but I'd say that markup tags
should count as word separators -- especially things like images.  And separate
words should be rendered with a space between.

Example 4 shows the nasty, evil things that can happen when coalescing of
whitespace goes bad.  4a shows the mysterious disappearance of trailing
whitespace.  4b shows left-coalescing at its worst.  4c shows more or less
correct behaviour that is completely inconsistent with 4b.

Example 5 shows the effects of poor treatment of empty elements combined with
the effects of whitespace-coalescing.  Notice that eliminating the border in 5c
also, for reasons unknown, eliminates the whitespace.


Reproducible: Always
Steps to Reproduce:
View forthcoming attachment.

Comment 1

[Bryan Mills]

Attachment: 5 examples showing whitespace bugs

Comment 2

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

#1 is probably a duplicate
#2 is invalid, per CSS 2.1
#3 is also invalid
#4 and #5 may be invalid, depending on the definition of "at the beginning of a
line"

See http://www.w3.org/TR/2004/CR-CSS21-20040225/text.html#q8

Comment 3

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

And in the future, please limit yourself to one issue per bug.

Comment 4

[Bryan Mills]

In lieu of that CSS spec, #2 and #3 are in fact invalid (although I would argue
that that's a glaring problem in the CSS spec as it relates to stylistically
readable HTML code -- the placement of tags vs. whitespace in code should never
change the meaning of the code!).  I think that's actually an inconsistency
between the HTML spec and the CSS spec, but since the CSS is more explicit I'll
go along with it.

However, #1, #4, and #5 are definitely bugs because they are inconsistent --
especially the starting span tags that contain a single space but are rendered
with no space.  They are probably all symptoms of the same bug, which is why I
filed them all in the same bug report.

Comment 5

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

#1 is *very* different from #4 and #5.  In fact, it's very different from all
the other examples, and relates to an obscure SGML rule that nobody follows.

Comment 6

[Gervase Markham [:gerv]]

This is an automated message, with ID "auto-resolve01".

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