Minor Description
A <dual> with no name attribute gets an NPE in resolve.
<dual> says it uses common attributes. If so, it really should check and complain instead of blowing up cryptically.
Here's a test-caseish description:
<ivysettings>
<settings defaultResolver="x" />
<resolvers>
<chain name="vendor-1">
<dual >
<filesystem name="vendor1-ivy" checkmodified="true" changingPattern=".*">
<ivy pattern="${vendor.dir}/vendor1-ivy/[organization]-ivy.xml" />
</filesystem>
<filesystem name="vendor1-jars" checkmodified="true" changingPattern=".*">
<artifact pattern="${vendor.dir}/vendor1/[artifact].[ext]" />
</filesystem>
</dual>
</chain>
<chain name="x"> ... </chain>
</resolvers>
<modules>
<module organisation="com.vendor1" module="*" resolver="vendor1" />
</modules>
</ivysettings>
vendor1's module object has a resolver with no name, and it gets an NPE trying to cache that name inside DefaultRepositoryCacheManager.saveResolvers.
main[1] where
[1] java.util.Hashtable.put (Hashtable.java:394)
[2] java.util.Properties.setProperty (Properties.java:143)
[3] org.apache.ivy.core.cache.DefaultRepositoryCacheManager.saveResolvers (DefaultRepositoryCacheManager.java:423)
[4] org.apache.ivy.core.resolve.IvyNode.loadData (IvyNode.java:176)
[5] org.apache.ivy.core.resolve.VisitNode.loadData (VisitNode.java:287)
[6] org.apache.ivy.core.resolve.ResolveEngine.fetchDependencies (ResolveEngine.java:696)
[7] org.apache.ivy.core.resolve.ResolveEngine.doFetchDependencies (ResolveEngine.java:781)
[8] org.apache.ivy.core.resolve.ResolveEngine.fetchDependencies (ResolveEngine.java:704)
[9] org.apache.ivy.core.resolve.ResolveEngine.doFetchDependencies (ResolveEngine.java:781)
[10] org.apache.ivy.core.resolve.ResolveEngine.fetchDependencies (ResolveEngine.java:704)
[11] org.apache.ivy.core.resolve.ResolveEngine.getDependencies (ResolveEngine.java:576)
[12] org.apache.ivy.core.resolve.ResolveEngine.resolve (ResolveEngine.java:237)
[13] org.apache.ivy.core.resolve.ResolveEngine.resolve (ResolveEngine.java:195)
[14] org.apache.ivy.Ivy.resolve (Ivy.java:502)
[15] org.apache.ivy.ant.IvyResolve.doExecute (IvyResolve.java:244)
[16] org.apache.ivy.ant.IvyTask.execute (IvyTask.java:277)
[17] org.apache.tools.ant.UnknownElement.execute (UnknownElement.java:291)
[18] sun.reflect.GeneratedMethodAccessor5.invoke (null)
[19] sun.reflect.DelegatingMethodAccessorImpl.invoke (DelegatingMethodAccessorImpl.java:25)
[20] java.lang.reflect.Method.invoke (Method.java:597)
[21] org.apache.tools.ant.dispatch.DispatchUtils.execute (DispatchUtils.java:106)
[22] org.apache.tools.ant.Task.perform (Task.java:348)
[23] org.apache.tools.ant.Target.execute (Target.java:390)
[24] org.apache.tools.ant.Target.performTasks (Target.java:411)
[25] org.apache.tools.ant.Project.executeSortedTargets (Project.java:1,360)
[26] org.apache.tools.ant.Project.executeTarget (Project.java:1,329)
[27] org.apache.tools.ant.helper.DefaultExecutor.executeTargets (DefaultExecutor.java:41)
[28] org.apache.tools.ant.Project.executeTargets (Project.java:1,212)
[29] org.apache.tools.ant.Main.runBuild (Main.java:801)
[30] org.apache.tools.ant.Main.startAnt (Main.java:218)
[31] org.apache.tools.ant.launch.Launcher.run (Launcher.java:280)
[32] org.apache.tools.ant.launch.Launcher.main (Launcher.java:109)
main[1]