Re: Bug report: Related to EXSLT date:add( )

On Fri, Nov 19, 2010 at 06:37:19PM +0100, Michael Ludwig wrote:
> money_seshu Dronamraju schrieb am 19.11.2010 um 10:20 (+0530):
> > 
> > Problem description:  EXSLT date:add() adds days to xs:gYearMonth/xs:gYear
> >  incorrectly when month is January
> > 
> > The following 2 expressions returns incorrect date:
> >    <xsl:value-of select="date:add( "2001-01", "P3D" )" />       -> returns
> > 2001-01
> >    <xsl:value-of select="date:add( "2001", "P12D" )')" />        -> returns
> > 2001
> > Ideally it should return   "2001-01-04" and "2001-01-13" respectively.
> > 
> > Root cause:
> > 
> > In  _exsltDateAdd(..,..) function ( libxslt/trunk/libexslt/date.c)
> > 
> > Because the month is January(1), "if" condition will never evaluate to true,
> > even though the day was changed , so it never returns return type as XS_DATE
> > 
> > Patch: attached.
> > 
> > Please provide your  comments.
> 
> I haven't tried your patch, but here's a standalone copy/paste testcase to
> confirm the issue:
> 
> <xsl:stylesheet version="1.0"
>   xmlns:date="http://exslt.org/dates-and-times"
>   exclude-result-prefixes="date"
>   xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
>   <xsl:output indent="yes"/>
>   <xsl:template match="/">
>     <dates-and-times>
>       <d><xsl:value-of select="date:add( '2001-01', 'P3D' )" /></d>
>       <d><xsl:value-of select="date:add( '2001-02', 'P3D' )" /></d>
>       <d><xsl:value-of select="date:add( '2001-12', 'P3D' )" /></d>
>       <d><xsl:value-of select="date:add( '2001-12', 'P30D' )" /></d>
>       <d><xsl:value-of select="date:add( '2001-12', 'P31D' )" /></d>
>       <d><xsl:value-of select="date:add( '2001-12', 'P32D' )" /></d>
>     </dates-and-times>
>   </xsl:template>
> </xsl:stylesheet>
> 
> $ xsltproc exslt-date.xsl exslt-date.xsl
> 
> <?xml version="1.0"?>
> <dates-and-times>
>   <d>2001-01</d>
>   <d>2001-02-04</d>
>   <d>2001-12-04</d>
>   <d>2001-12-31</d>
>   <d>2002-01</d>
>   <d>2002-01</d>
> </dates-and-times>
> 
> January seems problematic indeed.

  Okay, by applying the patch this looks indeed better:

paphio:~/XSLT/tests/general -> cat date_add.out
<?xml version="1.0"?>
<dates-and-times>
  <d>2001-01-04</d>
  <d>2001-02-04</d>
  <d>2001-12-04</d>
  <d>2001-12-31</d>
  <d>2002-01</d>
  <d>2002-01-02</d>
  </dates-and-times>
</dates-and-times>

  But should '2001-12' plus 31 days areally generate "2002-01" and not
  "2002-01-01", I'm wondering ?

Daniel
-- 
Daniel Veillard      | libxml Gnome XML XSLT toolkit  http://xmlsoft.org/
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