[Exist-development] help debugging "no supertype for empty()" warning when importing functx

[Joe W. <jo...@gm...>]

Hi all,

I am trying to find the source of the "no supertype for empty()"
warning that appears whenever I submit a query that imports the FunctX
module.  Steps to reproduce:

1. Using trunk, install the FunctX module

2. Submit the following query in eXide:

---
xquery version "3.0";

import module namespace functx="http://www.functx.com";

1
---

3. Observe the warning in exist.log:

2012-12-29 01:31:58,431 [eXistThread-48] WARN  (Type.java
[getSuperType]:396) - no supertype for empty()
java.lang.Throwable
at org.exist.xquery.value.Type.getSuperType(Type.java:396)
at org.exist.xquery.value.Type.getCommonSuperType(Type.java:422)
at org.exist.xquery.ConditionalExpression.returnsType(ConditionalExpression.java:149)
at org.exist.xquery.PathExpr.returnsType(PathExpr.java:393)
at org.exist.xquery.CastExpression.setExpression(CastExpression.java:63)
at org.exist.xquery.CastExpression.<init>(CastExpression.java:54)
at org.exist.xquery.FunctionFactory.castExpression(FunctionFactory.java:299)
at org.exist.xquery.FunctionFactory.createFunction(FunctionFactory.java:92)
at org.exist.xquery.FunctionFactory.createFunction(FunctionFactory.java:57)
at org.exist.xquery.FunctionFactory.createFunction(FunctionFactory.java:53)
at org.exist.xquery.parser.XQueryTreeParser.functionCall(XQueryTreeParser.java:9740)
at org.exist.xquery.parser.XQueryTreeParser.primaryExpr(XQueryTreeParser.java:7008)
at org.exist.xquery.parser.XQueryTreeParser.expr(XQueryTreeParser.java:3632)
at org.exist.xquery.parser.XQueryTreeParser.functionDecl(XQueryTreeParser.java:5627)
at org.exist.xquery.parser.XQueryTreeParser.prolog(XQueryTreeParser.java:4823)
at org.exist.xquery.parser.XQueryTreeParser.libraryModule(XQueryTreeParser.java:4087)
at org.exist.xquery.parser.XQueryTreeParser.module(XQueryTreeParser.java:3923)
at org.exist.xquery.parser.XQueryTreeParser.xpath(XQueryTreeParser.java:3712)
at org.exist.xquery.XQuery.compile(XQuery.java:157)
at org.exist.xquery.XQuery.compile(XQuery.java:106)
at org.exist.xquery.XQuery.compile(XQuery.java:90)


I have read through this warning many times and cannot trace the cause
of the warning.  I would like to get to the bottom of the warning,
since it causes confusion.

I'd appreciate any tips you might have on debugging this issue.

Thanks,
Joe