Bug #34908 for XML-XPathEngine: Overload broken

Sat Apr 12 07:41:29 2008 gregor+debian [...] comodo.priv.at - Ticket created

Subject:	Overload broken
Date:	Sat, 12 Apr 2008 13:41:12 +0200
To:	bug-XML-XPathEngine [...] rt.cpan.org
From:	gregor herrmann <gregor+debian [...] comodo.priv.at>

Hi, in the Debian bug tracker we have a report that shows that overloading is broken in various modules. It was originally reported against XML::XPath but seems to still apply for XML::XPathEngine. The report (containing a proposed solution and a test script) can be found at http://bugs.debian.org/460297. Please consider looking into this issue. Thanks in advance, gregor (Debian Perl Group) -- .''`. http://info.comodo.priv.at/ | gpg key ID: 0x00F3CFE4 : :' : debian: the universal operating system - http://www.debian.org/ `. `' member of https://www.vibe.at/ | how to reply: http://got.to/quote/ `- NP: Beatles

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Mon Apr 14 04:19:33 2008 MIROD [...] cpan.org - Correspondence added

From:

MIROD [...] cpan.org

On Sat Apr 12 07:41:29 2008, gregor+debian@comodo.priv.at wrote: Show quoted text

> in the Debian bug tracker we have a report that shows that > overloading is broken in various modules. It was originally reported > against XML::XPath but seems to still apply for XML::XPathEngine. > > The report (containing a proposed solution and a test script) can be > found at http://bugs.debian.org/460297. Please consider looking into > this issue.

Thanks, Indeed the bug showed up in XML::XPathEngine. The fix I found though was not to set the fallback overload, but rather to get findvalue to return real strings as opposed to XML::XPathEngine::Literal objects. Those objects are useless outside of the XPath engine, so keeping them around doesn't seem to do anyone any good. Does this make sense? An updated version is at http://xmltwig.com/module/xml-xpathengine/ The bug will be tested through XML::DOM::XPath. __ mirod

Mon Apr 14 04:19:34 2008 The RT System itself - Status changed from 'new' to 'open'

Mon Apr 14 15:12:46 2008 gregor+debian [...] comodo.priv.at - Correspondence added

Subject:	Re: [rt.cpan.org #34908] Overload broken
Date:	Mon, 14 Apr 2008 21:11:17 +0200
To:	MIROD via RT <bug-XML-XPathEngine [...] rt.cpan.org>
From:	gregor herrmann <gregor+debian [...] comodo.priv.at>

On Mon, 14 Apr 2008 04:19:34 -0400, MIROD via RT wrote: Show quoted text

> > The report (containing a proposed solution and a test script) can be > > found at http://bugs.debian.org/460297. Please consider looking into > > this issue.

> Indeed the bug showed up in XML::XPathEngine. The fix I found though was > not to set the fallback overload, but rather to get findvalue to return > real strings as opposed to XML::XPathEngine::Literal objects. Those > objects are useless outside of the XPath engine, so keeping them around > doesn't seem to do anyone any good. > Does this make sense?

Thanks alot for your quick response! I've downloaded 0.10 and tried it with Niko's testscript xpathengine-test.pl from the Debian bug report. The error is indeed gone but the results are probably not what Alexander and Niko expected: $ PERLLIB=XML-XPathEngine-0.10/lib perl xpathengine-test.pl res is 0 res is 0 res is 0 If I dump $weights{$id}, I get "$VAR1 = '';"; in fact $id itself is empty in the first place. *some times later* My digging on the code ends at the new to_final_value() in lib/XML/XPathEngine/NodeSet.pm but maybe I'm doing something wrong ... Cheers, gregor -- .''`. http://info.comodo.priv.at/ | gpg key ID: 0x00F3CFE4 : :' : debian: the universal operating system - http://www.debian.org/ `. `' member of https://www.vibe.at/ | how to reply: http://got.to/quote/ `- NP: Peter Jones: Belle's reply

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Mon Apr 14 15:51:12 2008 xmltwig [...] gmail.com - Correspondence added

Subject:	Re: [rt.cpan.org #34908] Overload broken
Date:	Mon, 14 Apr 2008 21:50:52 +0200
To:	bug-XML-XPathEngine [...] rt.cpan.org
From:	mirod <xmltwig [...] gmail.com>

gregor+debian@comodo.priv.at via RT wrote: Show quoted text

> I've downloaded 0.10 and tried it with Niko's testscript > xpathengine-test.pl from the Debian bug report. The error is indeed > gone but the results are probably not what Alexander and Niko > expected: > > $ PERLLIB=XML-XPathEngine-0.10/lib perl xpathengine-test.pl > res is 0 > res is 0 > res is 0 > > If I dump $weights{$id}, I get "$VAR1 = '';"; in fact $id itself is > empty in the first place. > > *some times later* > > My digging on the code ends at the new to_final_value() in > lib/XML/XPathEngine/NodeSet.pm but maybe I'm doing something wrong

Yes, the test calls findvalue on the document object, it should be called on the node itself: my $id = $xp->findvalue ('@id', $component); $weights{$id} = $xp->findvalue ('@weight', $component); should be instead: my $id = $component->findvalue ('@id'); $weights{$id} = $component->findvalue ('@weight'); in $xp->findvalue ('@id', $component); the $component is ignored and what's returned is the id attribute for the document itself. Thanks for taking the time to look into this, I'll send the new version to CPAN tomorrow. -- mirod

Mon Apr 14 16:33:17 2008 gregor+debian [...] comodo.priv.at - Correspondence added

Subject:	Re: [rt.cpan.org #34908] Overload broken
Date:	Mon, 14 Apr 2008 22:32:39 +0200
To:	"xmltwig [...] gmail.com via RT" <bug-XML-XPathEngine [...] rt.cpan.org>
From:	gregor herrmann <gregor+debian [...] comodo.priv.at>

On Mon, 14 Apr 2008 15:51:20 -0400, xmltwig@gmail.com via RT wrote: Show quoted text

> > My digging on the code ends at the new to_final_value() in > > lib/XML/XPathEngine/NodeSet.pm but maybe I'm doing something wrong

> > Yes, the test calls findvalue on the document object, it should be > called on the node itself: > > my $id = $xp->findvalue ('@id', $component); > $weights{$id} = $xp->findvalue ('@weight', $component); > > should be instead: > > my $id = $component->findvalue ('@id'); > $weights{$id} = $component->findvalue ('@weight'); > > in $xp->findvalue ('@id', $component); the $component is ignored and > what's returned is the id attribute for the document itself.

Oh, this works indeed, great. Show quoted text

> Thanks for taking the time to look into this, I'll send the new version > to CPAN tomorrow.

Thanks! One minor point: It looks like the POD for findvalue in XPathEngine.pm is not yet up to date; it still mentions to_literal instead of to_final_value. Cheers, gregor -- .''`. http://info.comodo.priv.at/ | gpg key ID: 0x00F3CFE4 : :' : debian: the universal operating system - http://www.debian.org/ `. `' member of https://www.vibe.at/ | how to reply: http://got.to/quote/ `- NP: Tom Waits: Shiver Me Timbers

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Mon Apr 14 16:56:54 2008 xmltwig [...] gmail.com - Correspondence added

Subject:	Re: [rt.cpan.org #34908] Overload broken
Date:	Mon, 14 Apr 2008 22:56:48 +0200
To:	bug-XML-XPathEngine [...] rt.cpan.org
From:	mirod <xmltwig [...] gmail.com>

gregor+debian@comodo.priv.at via RT wrote: Show quoted text

> One minor point: It looks like the POD for findvalue in > XPathEngine.pm is not yet up to date; it still mentions to_literal > instead of to_final_value.

Nice catch, Fixed, and version 0.10 is on its way to a CPAN mirror near you. Thanks -- mirod

Mon Apr 14 17:08:47 2008 gregor+debian [...] comodo.priv.at - Correspondence added

Subject:	Re: [rt.cpan.org #34908] Overload broken
Date:	Mon, 14 Apr 2008 23:08:33 +0200
To:	"xmltwig [...] gmail.com via RT" <bug-XML-XPathEngine [...] rt.cpan.org>
From:	gregor herrmann <gregor+debian [...] comodo.priv.at>

On Mon, 14 Apr 2008 16:56:55 -0400, xmltwig@gmail.com via RT wrote: Show quoted text

> Fixed, and version 0.10 is on its way to a CPAN mirror near you.

Great, I'll update the Debian package ASAP. Cheers, gregor -- .''`. http://info.comodo.priv.at/ | gpg key ID: 0x00F3CFE4 : :' : debian: the universal operating system - http://www.debian.org/ `. `' member of https://www.vibe.at/ | how to reply: http://got.to/quote/ `- NP: Aziza Mustafà Zadeh: Carnival

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Thu May 07 03:29:19 2009 MIROD [...] cpan.org - Status changed from 'open' to 'resolved'

Thu May 07 03:29:19 2009 MIROD [...] cpan.org - Fixed in 0.10 added