420532 - Incorrect "XML Parsing Error: mismatched tag."; sensitive to exact number of bytes before supposed error.

Status: RESOLVED WORKSFORME

(Firefox :: General, defect)

Description

[Ran]

User-Agent:       Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.8.1.12) Gecko/20080201 Firefox/2.0.0.12
Build Identifier: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.8.1.12) Gecko/20080201 Firefox/2.0.0.12

I can't give exact details, because I don't understand them, but for me, when Firefox loads the test-case I'll attach in a moment, it shows this error message:

XML Parsing Error: mismatched tag. Expected: </head>.
Location: file:///C:/Firefox-parser-bug.xml
Line Number 59, Column 4:

 </head>
---^

This bug is very sensitive - for example, adding or removing a single byte from within the <style> element will fix the file. Changing a byte won't fix the file - though sometimes the error will switch to being about </html> instead of </head>. (I haven't detected a pattern in which one it will barf on.)

Incidentally, the test-case is likely Windows-specific, in that a newline appears to be equivalent to two hyphens. (Anyone on a Unix system can probably run dos2unix on the test-case and get the same effect, but who knows?)

By the way, the Error Console also shows two copies of a "missing ; before statement" error during the DOCTYPE declaration, but only on this version of the file; other versions of the file that also trigger the bug do not all cause that error, so I'm not sure it's relevant.

Reproducible: Always

Steps to Reproduce:
1. Come visit me at home, and ask to use my computer. (This may or may not affect anyone else's, though I don't think there's anything particularly special about my system.)
2. Load the soon-to-be-attached XML file in Firefox.
Actual Results:  
XML parser error, complaining that it expected one thing and got the same thing.

Expected Results:  
A blank document.

I'm using the default theme; my only extensions are Copy Plain Text, StumbleUpon, and TalkBack.

Comment 1

[Ran]

Attachment: test-case

Comment 2

[Ran]

Fortunately or otherwise, this bug does *not* appear to occur on my work computer - same build of Firefox, no add-ons. I don't know if the issue could be caused by one of the add-ons. :-/

Comment 3

[Ran]

I've now removed all add-ons except TalkBack, and I still get this error.

Comment 4

[Ran]

Given that I opened this bug more than a year and a half ago, and more than a version and a half ago, I think it's safe to close this now. (The test case no longer triggers a problem, at least on my machine.) Hopefully whatever bug this was has been fixed since then, and if not, someone can open a new ticket when they encounter it.