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Re: XHTML validation bug (false pass)

From: Gerald Oskoboiny <gerald@w3.org>
Date: Thu, 24 Feb 2000 17:30:37 -0500
To: David Brownell <david-b@pacbell.net>
Cc: Terje Bless <link@tss.no>, W3C Validator <www-validator@w3.org>
Message-ID: <20000224173036.B32199@w3.org>
On Sun, Feb 20, 2000 at 11:22:54AM -0500, David Brownell wrote:
> Terje Bless wrote:
> > On 19.02.00 at 20:10, David Brownell <david-b@pacbell.net> wrote:
> > >Basically, it accepts blank lines before XML/text declarations, which are
> > >explicitly not permitted in the grammar:  no whitespace before either of
> > >those, and the same syntax elsewhere in the document body (e.g. after the
> > >newline) counts as an illegal processing instruction
:
> ... the following isn't reported as a fatal error:
> 
> 	Line 1:		
> 	Line 2:		<?xml version="1.0"?>
> 	Lines 3-N:	irrelevant

Thanks for the info, I added that as a test case:

    http://validator.w3.org/dev/tests/xhtml1-blank-1st-line.html

> That malformed input is ignored, which is the problem.  I didn't try any
> related inputs to try to characterize the bug any further.
> 
> It does make me wonder how many other illegal XML constructs are passing
> through there.

When I added the xhtml support recently, I intended for the
output to include a "caveat" blurb linked to information on SP's
XML limitations:

    http://www.jclark.com/sp/xml.htm

but I messed it up and this caveat was only being included for
(non-xhtml) XML validations, not XHTML.

That's fixed now; all XHTML validations include a link to that
description of SP's limitations.

> > Well, in general, throwing fatal exceptions isn't really
> > usefull behaviour for a validation tool. Is there some reason
> > this should be changed in tis case?
> 
> To report the error?  Absolutely -- it's telling folk that seriously
> broken XML is valid, when it's not even well formed.
> 
> It should at least be telling them that any conformant XML tool will
> refuse to even _read_ the document.  As it is, it's giving them a W3C
> stamp of approval -- wrong answer!

That doesn't seem good, indeed. I thought SP's XML limitations
sounded like obscure things that wouldn't come up much in
practice, but that doesn't seem to be the case.

I guess I'll have to have a look at expat or something else as a
replacement.

-- 
Gerald Oskoboiny       <gerald@w3.org>  +1 617 253 2920
System Administrator   http://www.w3.org/People/Gerald/
World Wide Web Consortium (W3C)      http://www.w3.org/
Received on Thursday, 24 February 2000 17:30:43 GMT

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