Getting SXST0060 "No streamable path found in expression" when trying to push a map with grounded nodes to a template of a streamable mode

I have run into an odd error while trying to find an elegant way to pass some grounded nodes on from a streamed xsl:iterate to a template to create a secondary result, I tried to write a template matching on .[. instance of map(xs:string, element()?)] and then to construct a result-document in there, however, while executing the code Saxon 9.9.0.1 EE gives me an error

SXST0060: Component cannot be streamed, although it is guaranteed streamable according to W3C rules. No streamable path found in expression ($current-item, ...) Component cannot be streamed, although it is guaranteed streamable according to W3C rules. No streamable path found in expression ($current-item, ...)

Here are the details, the XSLT is

<?xml version="1.0" encoding="UTF-8"?>
<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
    xmlns:xs="http://www.w3.org/2001/XMLSchema" exclude-result-prefixes="#all" expand-text="yes"
    version="3.0">
    
    <xsl:param name="STREAMABLE" static="yes" as="xs:boolean" select="true()"/>
    
    <xsl:mode _streamable="{$STREAMABLE}"/>
    
    <xsl:output method="html" indent="yes" version="5.0"/>
    
    <xsl:template match=".[. instance of map(xs:string, element()?)]">
        <xsl:param name="current-item" as="element()" select="?current-item"/>
        <xsl:param name="previous-item" as="element()?" select="?previous-item"/>
        <xsl:param name="next-item" as="element()?" select="?next-item"/>
        <xsl:message select="'item-doc', ., $current-item, $previous-item, $next-item"/>
        <xsl:for-each select="$current-item">
            
            <xsl:result-document href="item_{@id}.html">
                <html>
                    <head>
                        <title>Item {@id}</title>
                    </head>
                    <body>
                        <h1>Item {@id}</h1>
                        <nav>
                            <xsl:if test="$previous-item">
                                <a href="item_{$previous-item/@id}.html">prev</a>
                            </xsl:if>
                            <xsl:if test="$next-item">
                                <a href="item_{$next-item/@id}.html">next</a>
                            </xsl:if>
                        </nav>
                    </body>
                </html>
            </xsl:result-document>
        </xsl:for-each>
    </xsl:template>
    
    <xsl:template match="/">
        <html>
            <head>
                <title>Testing xsl:iterate</title>
            </head>
            <body>
                <h1>Testing xsl:iterate</h1>
                <section>
                    <h2>Results</h2>
                    <xsl:apply-templates/>
                </section>
            </body>
        </html>
    </xsl:template>
    
    <xsl:template match="items">
        <ul>
            <xsl:fork>
                <xsl:sequence>
                    <xsl:apply-templates select="item"/>
                </xsl:sequence>
                <xsl:sequence>
                    <xsl:iterate select="item">
                        <xsl:param name="previous-item" as="element(item)?" select="()"/>
                        <xsl:param name="current-item" as="element(item)*" select="()"/>
                        
                        <xsl:on-completion>
                            <xsl:message select="'remaing'"/>
                            <xsl:apply-templates select="map { 'current-item' : $current-item, 'previous-item' : $previous-item }"/>
                        </xsl:on-completion>
                        
                        <xsl:variable name="this-item" select="copy-of()"/>
                        
                        <xsl:if test="position() gt 1">
                            <xsl:apply-templates select="map { 'current-item' : $current-item, 'previous-item' : $previous-item, 'next-item' : $this-item }"/>
                        </xsl:if>
                        
                        <xsl:next-iteration>
                            <xsl:with-param name="current-item" select="$this-item"/>
                            <xsl:with-param name="previous-item" select="$current-item"/>
                        </xsl:next-iteration>
                        
                    </xsl:iterate>
                </xsl:sequence>
            </xsl:fork>
        </ul>
    </xsl:template>
    
    <xsl:template match="item">
        <li>Item {@id}, position: {position()}, attribute pos: {@pos}</li>
    </xsl:template>
    
</xsl:stylesheet>

A sample XML input is

<?xml version="1.0" encoding="UTF-8"?>
<items>
   <item id="i1" pos="1">
      <data>data 1</data>
   </item>
   <item id="i2" pos="2">
      <data>data 2</data>
   </item>
   <item id="i3" pos="3">
      <data>data 3</data>
   </item>
   <item id="i4" pos="4">
      <data>data 4</data>
   </item>
   <item id="i5" pos="5">
      <data>data 5</data>
   </item>
</items>

Full error message I get is

Error evaluating ((if(fn:position() gt 1) then ... else ..., ...)) in xsl:param/@select on line 13 column 79 of iterate-test5.xsl: SXST0060: Component cannot be streamed, although it is guaranteed streamable according to W3C rules. No streamable path found in expression ($current-item, ...) Component cannot be streamed, although it is guaranteed streamable according to W3C rules. No streamable path found in expression ($current-item, ...)

I can work around the problem by putting that template matching the map into a non-streamable mode and applying that when I push the map to the template but I would like to know whether the above should work or whether the streamability analysis failed to reject the approach.

Download all files

input5.xml (370 Bytes) input5.xml
iterate-test5.xsl (3.71 KB) iterate-test5.xsl

Replies (1)

Getting SXST0060 "No streamable path found in expression" when trying to push a map with grounded nodes to a template of a streamable mode - Added by Community Admin over 5 years ago

Problem reproduced. Saved as XSLT3 test case si-fork-119. Entered as bug 3934.

I'm not currently sure whether this should be streamable or not. But the diagnostics in both 9.8 and 9.9 could be improved.

Michael Kay Saxonica

On 2 Oct 2018, at 10:41, Saxonica Developer Community notifications@plan.io wrote:

(1-1/1)

Please register to reply

Project

Profile

Help

Saxon