Bug #3195: Duplicate binding slot assignment - Saxon - Saxonica Developer Community

Actions

Send by e-mail Copy link

Bug #3195

closed

Duplicate binding slot assignment

Added by Radu Coravu about 7 years ago. Updated almost 7 years ago.

Status:

Closed

Priority:

Normal

Assignee:

Category:

Sprint/Milestone:

Start date:

2017-04-07

Due date:

% Done:

100%

Estimated time:

Legacy ID:

Applies to branch:

9.7

Fix Committed on Branch:

9.7, trunk

Fixed in Maintenance Release:

9.7.0.19

Platforms:

Description

One of our users reported this problem when publishing DITA to PDF using their own XSLT customizations which may not be properly constructed. The problem cannot be reproduced with an older Saxon library.

When I obtain some sample XSLT code from them I will try to add more details to the issue:

https://www.oxygenxml.com/forum/viewtopic.php?f=20&t=14355&p=42301#p42295

Duplicate binding slot assignment
   at net.sf.saxon.expr.GlobalVariableReference.setBindingSlot(GlobalVariableReference.java:60)
   at net.sf.saxon.expr.instruct.ComponentCode.processComponentReference(ComponentCode.java:140)
   at net.sf.saxon.expr.instruct.ComponentCode.allocateBindingSlotsRecursive(ComponentCode.java:106)
   at net.sf.saxon.expr.instruct.ComponentCode.allocateBindingSlotsRecursive(ComponentCode.java:109)
   at net.sf.saxon.expr.instruct.ComponentCode.allocateBindingSlotsRecursive(ComponentCode.java:109)
   at net.sf.saxon.expr.instruct.ComponentCode.allocateBindingSlotsRecursive(ComponentCode.java:109)
   at net.sf.saxon.expr.instruct.ComponentCode.allocateBindingSlotsRecursive(ComponentCode.java:109)
   at net.sf.saxon.expr.instruct.ComponentCode.allocateBindingSlotsRecursive(ComponentCode.java:109)
   at net.sf.saxon.expr.instruct.ComponentCode.allocateBindingSlotsRecursive(ComponentCode.java:109)
   at net.sf.saxon.expr.instruct.ComponentCode.allocateBindingSlotsRecursive(ComponentCode.java:109)
   at net.sf.saxon.expr.instruct.ComponentCode.allocateBindingSlotsRecursive(ComponentCode.java:109)
   at net.sf.saxon.expr.instruct.ComponentCode.allocateBindingSlotsRecursive(ComponentCode.java:109)
   at net.sf.saxon.expr.instruct.ComponentCode.allocateBindingSlotsRecursive(ComponentCode.java:109)
   at net.sf.saxon.expr.instruct.ComponentCode.allocateBindingSlotsRecursive(ComponentCode.java:109)
   at net.sf.saxon.expr.instruct.ComponentCode.allocateAllBindingSlots(ComponentCode.java:100)
   at net.sf.saxon.style.PrincipalStylesheetModule.compile(Unknown Source)
   at net.sf.saxon.style.Compilation.compilePackage(Compilation.java:265)
   at net.sf.saxon.style.StylesheetModule.loadStylesheet(StylesheetModule.java:260)
   at net.sf.saxon.style.Compilation.compileSingletonPackage(Compilation.java:101)
   at net.sf.saxon.s9api.XsltCompiler.compile(XsltCompiler.java:859)
   at net.sf.saxon.jaxp.SaxonTransformerFactory.newTemplates(Unknown Source)
   at org.apache.tools.ant.taskdefs.optional.TraXLiaison.readTemplates(TraXLiaison.java:310)
   at org.apache.tools.ant.taskdefs.optional.TraXLiaison.createTransformer(TraXLiaison.java:328)
   at org.apache.tools.ant.taskdefs.optional.TraXLiaison.transform(TraXLiaison.java:188)
   at org.apache.tools.ant.taskdefs.XSLTProcess.process(XSLTProcess.java:881)
   at org.apache.tools.ant.taskdefs.XSLTProcess.execute(XSLTProcess.java:419)
   at org.apache.tools.ant.UnknownElement.execute(UnknownElement.java:293)
   at sun.reflect.GeneratedMethodAccessor4.invoke(Unknown Source)
   at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
   at java.lang.reflect.Method.invoke(Unknown Source)
   at org.apache.tools.ant.dispatch.DispatchUtils.execute(DispatchUtils.java:106)
   at org.apache.tools.ant.Task.perform(Task.java:348)
   at org.apache.tools.ant.Target.execute(Target.java:435)
   at org.apache.tools.ant.Target.performTasks(Target.java:456)
   at org.apache.tools.ant.Project.executeSortedTargets(Project.java:1405)
   at org.apache.tools.ant.helper.SingleCheckExecutor.executeTargets(SingleCheckExecutor.java:38)
   at org.apache.tools.ant.Project.executeTargets(Project.java:1260)
   at org.apache.tools.ant.taskdefs.Ant.execute(Ant.java:441)
   at org.apache.tools.ant.taskdefs.CallTarget.execute(CallTarget.java:105)
   at org.apache.tools.ant.UnknownElement.execute(UnknownElement.java:293)
   at sun.reflect.GeneratedMethodAccessor4.invoke(Unknown Source)
   at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
   at java.lang.reflect.Method.invoke(Unknown Source)
   at org.apache.tools.ant.dispatch.DispatchUtils.execute(DispatchUtils.java:106)
   at org.apache.tools.ant.Task.perform(Task.java:348)
   at org.apache.tools.ant.Target.execute(Target.java:435)
   at org.apache.tools.ant.Target.performTasks(Target.java:456)
   at org.apache.tools.ant.Project.executeSortedTargets(Project.java:1405)
   at org.apache.tools.ant.helper.SingleCheckExecutor.executeTargets(SingleCheckExecutor.java:38)
   at org.apache.tools.ant.Project.executeTargets(Project.java:1260)
   at org.apache.tools.ant.taskdefs.Ant.execute(Ant.java:441)
   at org.apache.tools.ant.taskdefs.CallTarget.execute(CallTarget.java:105)
   at org.apache.tools.ant.UnknownElement.execute(UnknownElement.java:293)
   at sun.reflect.GeneratedMethodAccessor4.invoke(Unknown Source)
   at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
   at java.lang.reflect.Method.invoke(Unknown Source)
   at org.apache.tools.ant.dispatch.DispatchUtils.execute(DispatchUtils.java:106)
   at org.apache.tools.ant.Task.perform(Task.java:348)
   at org.apache.tools.ant.Target.execute(Target.java:435)
   at org.apache.tools.ant.Target.performTasks(Target.java:456)
   at org.apache.tools.ant.Project.executeSortedTargets(Project.java:1405)
   at org.apache.tools.ant.helper.SingleCheckExecutor.executeTargets(SingleCheckExecutor.java:38)
   at org.apache.tools.ant.Project.executeTargets(Project.java:1260)
   at org.apache.tools.ant.taskdefs.Ant.execute(Ant.java:441)
   at org.apache.tools.ant.taskdefs.CallTarget.execute(CallTarget.java:105)
   at org.apache.tools.ant.UnknownElement.execute(UnknownElement.java:293)
   at sun.reflect.GeneratedMethodAccessor4.invoke(Unknown Source)
   at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
   at java.lang.reflect.Method.invoke(Unknown Source)
   at org.apache.tools.ant.dispatch.DispatchUtils.execute(DispatchUtils.java:106)
   at org.apache.tools.ant.Task.perform(Task.java:348)
   at org.apache.tools.ant.Target.execute(Target.java:435)
   at org.apache.tools.ant.Target.performTasks(Target.java:456)
   at org.apache.tools.ant.Project.executeSortedTargets(Project.java:1405)
   at org.apache.tools.ant.Project.executeTarget(Project.java:1376)
   at org.apache.tools.ant.helper.DefaultExecutor.executeTargets(DefaultExecutor.java:41)
   at org.apache.tools.ant.Project.executeTargets(Project.java:1260)
   at org.apache.tools.ant.Main.runBuild(Main.java:857)
   at org.apache.tools.ant.Main.startAnt(Main.java:236)
   at org.apache.tools.ant.launch.Launcher.run(Launcher.java:287)
   at org.apache.tools.ant.launch.Launcher.main(Launcher.java:113)

Actions

Copy link

Updated by Michael Kay about 7 years ago

Never seen that particular symptom before, except during development. It probably means that the same variable reference is reachable by more than one route in the expression tree, which means that some rewrite process has failed to observe the protocol of always making a copy. Will need a repro to resolve it.

Actions

Copy link

Updated by Radu Coravu about 7 years ago

I got the samples from my end user, they are a DITA Open Toolkit 1.8.5 PDF customization plugin containing a bunch of XSLT stylesheets being imported with high priority in the XSLT stylesheets from the DITA OT base PDF plugin.

One of those stylesheets defines a variable like this:

   <xsl:variable name="column.set">2</xsl:variable>

and then uses it a little further down like this:

<xsl:attribute-set name="column.two">
      <xsl:attribute name="column-count">
         <xsl:value-of select="$column.set"/>
      </xsl:attribute>
   </xsl:attribute-set>

I removed all references to that "column.two" attribute set (it was referenced in other attribute sets) but the error still occurs so somehow that reference to $column.set from the attribute set generates the problem.

Actions

Copy link

Updated by Michael Kay about 7 years ago

The fact that the variable reference is within an attribute set certainly provides a very significant clue. However, I haven't been able to reproduce the problem, or to see anything wrong by code inspection, so there must be some other factor at play.

Do you know whether there is only one attribute set declaration with this name?

Under the failure conditions, what references to the attribute set exist?

Are there any references to the global variable other than the reference in the attribute set?

Actions

Copy link

Updated by Michael Kay about 7 years ago

My suspicions are falling on PrincipalStylesheetModule.combineAttributeSets() which creates an AttributeSet from all the xsl:attribute-set declarations that share the same name. If somehow a single xsl:attribute-set were present in this list more than once, then the variable reference would be processed more than once, leading to the observed effect. I'm wondering if this could happen through multiple includes/imports of a stylesheet module?

OK: I've reproduced it by declaring the attribute-set in a module and doing two xsl:includes on that module:

Warning at xsl:stylesheet on line 5 column 17 of test1.xsl:

Stylesheet module file:/Users/mike/Desktop/temp/test1.xsl is included or imported more

than once. This is permitted, but may lead to errors or unexpected behavior

Exception in thread "main" java.lang.AssertionError: Duplicate binding slot assignment

The warning is pertinent!

Actions

Copy link

Updated by Michael Kay about 7 years ago

Status changed from New to Resolved
Applies to branch 9.7, 9.8 added
Fix Committed on Branch 9.7, 9.8 added

Produced a patch to combineAttributeSets() to ensure that if two instances of the same xsl:attribute-set are present, only the last is retained.

Added W3C test case attribute-set-1815.

Actions

Copy link

Updated by Radu Coravu about 7 years ago

Your analysis is 100% correct, the XSLT stylesheet was included from two places. And you also saved me 30 minutes of trying to put together a set of sample stylesheets.

I will try to include the patch in the next Oxygen 19.0 minor bug fix release.

We also got a StackOverflowException reported:

https://www.oxygenxml.com/forum/viewtopic.php?f=1&t=14382&p=42408#p42408

but that's another story, I will add a separate issue for it...

Actions

Copy link