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Support #1629

closed

Strange recursive behaviour in stylesheet

Added by O'Neil Delpratt about 12 years ago. Updated about 12 years ago.

Status:
Rejected
Priority:
Normal
Category:
Internals
Sprint/Milestone:
-
Start date:
2012-09-18
Due date:
% Done:

0%

Estimated time:
Legacy ID:
Applies to branch:
Fix Committed on Branch:
Fixed in Maintenance Release:
Platforms:

Description

Reported by Jesper Tverskov:

This error can be reproduced with the attached stylesheet.

  1. If the row count, "rcount", is lower than 9, the recursion works.

If it is 9 the number of rows returned explodes. If it is higher than

9 no rows are returned.

  1. It is easy to fix the templates, I can do one of two:

If I change:

xsl:with-param

<xsl:value-of select="$i + 1"/>

</xsl:with-param>

to:

<xsl:with-param select="$i + 1"/>

Everything is ok.

It is also ok if I change it to:

<xsl:with-param as="xs:integer">

<xsl:value-of select="$i + 1"/>

</xsl:with-param>


Files

stylesheet.xsl (1.93 KB) stylesheet.xsl O'Neil Delpratt, 2012-09-18 09:30
Actions #1

Updated by O'Neil Delpratt about 12 years ago

  • File stylesheet.xsl stylesheet.xsl added
  • Subject changed from NoSuchMethodException thrown by call to AtomicValue method getItemType to Strange recursive behaviour in stylesheet
  • Description updated (diff)
  • Category changed from Byte code generation to Internals
  • Status changed from Resolved to In Progress
  • % Done changed from 100 to 0
Actions #2

Updated by O'Neil Delpratt about 12 years ago

  • Status changed from In Progress to Rejected

This issue is not a bug. The use of xsl:value-of within xsl:with-param of the recursive calls returns a document with a text node (ref: http://www.w3.org/TR/xslt20/#element-value-of). At runtime we do not know the types of the parameter values. Hence, when calls are made on the parameters in the the comparison of xsl:if they are deemed as an untypedAtomic value.

As a result, according to the XPath 2.0 specification, if both atomic values are instances of xs:untypedAtomic, then the values are cast to the type xs:string. This means our comparisons is based on string values and not as integers. (Ref: http://www.w3.org/TR/xpath20/#id-general-comparisons) giving unpredictable results.

Actions #3

Updated by Michael Kay about 12 years ago

  • Tracker changed from Bug to Support
  • Priority changed from High to Normal
  • Found in version deleted (9.4)

Transferring to "Support" category so it doesn't come up in a bug search.

I would strongly recommend using the select attribute of xsl:with-param (and xsl:variable) etc wherever it's possible. At best, the use of an xsl:value-of causes a significant overhead because of the need to convert a number to a string, then to a text node, then to create a document wrapper, then to atomize this to untyped atomic, then to convert this back to a number. At worst, as shown here, it gives wrong results.

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