Bug #3534
closed
Simple map operator, fn:min
Category:
Byte code generation
Applies to branch:
9.7, 9.8, trunk
Fix Committed on Branch:
9.7, 9.8, trunk
Fixed in Maintenance Release:
Description
And yet another one (that may already have been fixed?): The query (1e0, 1) ! min(.) yields this:
java.lang.NullPointerException
at net.sf.saxon.expr.AtomicSequenceConverter$AtomicSequenceMappingFunction.mapItem(AtomicSequenceConverter.java:289)
at net.sf.saxon.expr.AtomicSequenceConverter$AtomicSequenceMappingFunction.mapItem(AtomicSequenceConverter.java:280)
at net.sf.saxon.expr.ItemMappingIterator.next(ItemMappingIterator.java:113)
at EE_main_01422222071.process(file:/c:/Users/user/Desktop/query.xq:1)
at com.saxonica.ee.bytecode.CompiledExpression.process(CompiledExpression.java:70)
at net.sf.saxon.query.XQueryExpression.run(XQueryExpression.java:408)
at net.sf.saxon.s9api.XQueryEvaluator.run(XQueryEvaluator.java:370)
at net.sf.saxon.Query.runQuery(Query.java:900)
at net.sf.saxon.Query.doQuery(Query.java:442)
at net.sf.saxon.Query.main(Query.java:111)
- Category set to Byte code generation
- Applies to branch 9.7 added
I can confirm that this is crashing in 9.7 but runs OK in 9.8.
- Status changed from New to In Progress
- Priority changed from Low to Normal
Turns out it isn't really fixed in 9.8 at all; it just requires a more subtle test because by default it's masked by hotspot bytecode generation.
The crash is because the static type of the first argument to min() is heterogeneous, and in consequence no converter has been allocated to handle run-time type conversion at the time bytecode is generated.
Running the interpreter under the debugger shows that it's behaving badly in that case too: the converter is allocated at run-time, but is written to the relevant node in the expression tree, causing potential multi-threading problems.
So the first part of the fix is to ensure that when a converter is allocated dynamically, the expression tree is not modified.
The second part (which fixes the bug observed here) is to force allocation of a converter before generating bytecode.
The final part is more specific to the min() function. The min() and max() functions convert untyped atomic values to xs:double regardless of the type of the other items in the sequence. So there's no good reason to delay allocating a converter until the static type of the sequence is more precisely known: it won't make any difference. This can be achieved by changing Minimax.optimizeFunctionCall() to call the factory method UntypedSequenceConverter.makeUntypedSequenceConverter() in place of the simple constructor.
- Status changed from In Progress to Resolved
- Applies to branch 9.8, trunk added
- Fix Committed on Branch 9.7, 9.8, trunk added
Made the above fixes on the 9.7, 9.8, and 9.9 branches.
- % Done changed from 0 to 100
- Fixed in Maintenance Release 9.7.0.21 added
Bug fix applied in the Saxon 9.7.0.21 maintenance release.
Bug fix applied in the Saxon 9.8.0.7 maintenance release.
- Status changed from Resolved to Closed
- Fixed in Maintenance Release 9.8.0.7 added
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