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$source-doc variable wrongly evaluated
Added by Anonymous almost 19 years ago
Legacy ID: #3450631
Legacy Poster: Evan Lenz (elenz)
Hello Michael, I stumbled over a juicy bug when working with 6.5.3, and I confirmed
that it's still a problem in 6.5.5. To reproduce, run this stylesheet against a document
other than itself: <xsl:stylesheet version="1.0"
xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:variable name="VAR1"> <xsl:for-each
select="document('')"> <xsl:value-of
select="$source-doc"/> </xsl:for-each>
</xsl:variable> <xsl:variable name="source-doc"
select="/"/> <xsl:template
match="/"> <!-- This should copy the source document;
instead it copies the stylesheet document --> <xsl:copy-of
select="$source-doc"/> </xsl:template>
</xsl:stylesheet> Even though $VAR1 isn't used, its definition causes
$source-doc to be incorrectly evaluated, as if the expression "/" were
evaluated inline in the context in which $source-doc is first referenced (inside the
$VAR1 definition). This has a sticky effect, causing all subsequent evaluations to be
wrong. My workaround was to move the $source-doc definition above the $VAR1 definition
so that it comes first. Evan
Legacy ID: #3450765
Legacy Poster: Michael Kay (mhkay)
Thanks Evan, certainly a juicy bug. It's amazing how long such things can lurk (and
of course, how they always emerge a week or so after the first release in months or
years). Saxon 6.x evaluates global variables eagerly (before it does anything else) and
generally they are evaluated each in turn; however if there's a forwards reference from
one global variable to another then the referenced variable is evaluated when the
reference is encountered, and it seems it is evaluated with the context set to exactly
what it is at the point where the variable reference appears. I've fixed the source
code, it will probably take a while before I do another release. Michael Kay
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