[jira] [Resolved] (JEXL-246) Intermittent ambiguous method invocation when processing assignOverload

["Henri Biestro (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/JEXL-246?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Henri Biestro resolved JEXL-246.
--------------------------------
       Resolution: Fixed
    Fix Version/s: 3.2

The behavior is not intermittent; when JEXL detects an ambiguity when resolving a method, it will log this exception as an info (using the JEXL engine logger if configured to allow these) and will remember this signature as a cache-miss. The second time this resolution is attempted, the cache-miss will be detected to return a null (and avoid throwing the same exception twice).
In effect, the MethodKey.AmbiguousException will only be logged once (per lifetime of the Introspector).

The fix though is to make it clearer what the error is due to; in the accompanying case, it is due to a null operand (z) during operator evaluation.

trunk/RELEASE-NOTES.txt
trunk/src/main/java/org/apache/commons/jexl3/internal/Operators.java
trunk/src/site/xdoc/changes.xml
trunk/src/test/java/org/apache/commons/jexl3/IssuesTest200.java

Committed revision 1820568.

> Intermittent ambiguous method invocation when processing assignOverload
> -----------------------------------------------------------------------
>
>                 Key: JEXL-246
>                 URL: https://issues.apache.org/jira/browse/JEXL-246
>             Project: Commons JEXL
>          Issue Type: Bug
>    Affects Versions: 3.1
>            Reporter: Dmitri Blinov
>            Assignee: Henri Biestro
>            Priority: Minor
>             Fix For: 3.2
>
>
> Sometimes the simple operator like {code}z += 1{code} when {{z}} has not been defined yet raises an exception {{org.apache.commons.jexl3.internal.introspection.MethodKey$AmbiguousException}} with the following stack trace: 
> {quote}
> ambiguous method invocation: MyArithmetic.selfAdd(null, java.lang.Integer)
> org.apache.commons.jexl3.internal.introspection.MethodKey$AmbiguousException: null
> 	at org.apache.commons.jexl3.internal.introspection.MethodKey$Parameters.getMostSpecific(MethodKey.java:540)
> 	at org.apache.commons.jexl3.internal.introspection.MethodKey$Parameters.access$000(MethodKey.java:452)
> 	at org.apache.commons.jexl3.internal.introspection.MethodKey.getMostSpecificMethod(MethodKey.java:261)
> 	at org.apache.commons.jexl3.internal.introspection.ClassMap.getMethod(ClassMap.java:178) 
> 	at org.apache.commons.jexl3.internal.introspection.Introspector.getMethod(Introspector.java:146)
> 	at org.apache.commons.jexl3.internal.introspection.MethodExecutor.discover(MethodExecutor.java:52)
> 	at org.apache.commons.jexl3.internal.introspection.Uberspect.getMethod(Uberspect.java:218) 
> 	at MyUberspect.getMethod(MyUberspect.java:168)
> 	at org.apache.commons.jexl3.internal.introspection.Uberspect$ArithmeticUberspect.getOperator(Uberspect.java:413)
> 	at org.apache.commons.jexl3.internal.Operators.tryOverload(Operators.java:85) 
> 	at org.apache.commons.jexl3.internal.Operators.tryAssignOverload(Operators.java:118) 
> 	at org.apache.commons.jexl3.internal.Interpreter.executeAssign(Interpreter.java:1292) 
> 	at org.apache.commons.jexl3.internal.Interpreter.visit(Interpreter.java:1102) 
> ....
> {quote}
> The class MyArithmetic contains a couple of overloaded
> {{public JexlOperator selfAdd(T x, Object y)}} methods with the first argument being the desired type {{T}} like {{Appendable}} or {{Collection}} for which the {{+=}} operator is overloaded.
> Obviously in case where the first argument is null and the second argument is an Integer it is not possible to differentiate between {{public JexlOperator selfAdd(Collection x, Object y)}} and {{public JexlOperator selfAdd(Appendable x, Object y)}} but I wonder is there any point in trying to perform {{selfAdd}} on the null variable? What questions me more is that this error is intermittent and sometimes there is an exception and sometimes there is not, so at the moment I have no test case to reproduce. So I think this is a bug.



--
This message was sent by Atlassian JIRA
(v6.4.14#64029)