Description Paul Webster 2013-12-11 13:17:33 EST

backport into 4.3.2

+++ This bug was initially created as a clone of Bug #422034 +++

The HandlerProcessingAddon casts an MHandlerContainer to an MContext without checking if the MHandlerContainer is of type MContext. 

As this is true for most of the classes implementing MHandlerContainer, it is not true for all. One example is MPartDescriptor. The HandlerProcessingAddon fails with an ClassCastException if one removes an MHandler from an MPartDescriptor.


For 4.3.1 the stacktrace is as follows:
java.lang.ClassCastException: org.eclipse.e4.ui.model.application.descriptor.basic.impl.PartDescriptorImpl cannot be cast to org.eclipse.e4.ui.model.application.ui.MContext
	at org.eclipse.e4.ui.internal.workbench.addons.HandlerProcessingAddon$1.handleEvent(HandlerProcessingAddon.java:88) ~[na:na]
	at org.eclipse.e4.ui.services.internal.events.UIEventHandler$1.run(UIEventHandler.java:41) ~[na:na]
	at org.eclipse.swt.widgets.RunnableLock.run(RunnableLock.java:35) ~[na:na]
	at org.eclipse.swt.widgets.Synchronizer.runAsyncMessages(Synchronizer.java:135) ~[na:na]
	at org.eclipse.swt.widgets.Display.runAsyncMessages(Display.java:4145) ~[na:na]
	at org.eclipse.swt.widgets.Display.readAndDispatch(Display.java:3762) ~[na:na]
	at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine$9.run(PartRenderingEngine.java:1113) ~[na:na]
	at org.eclipse.core.databinding.observable.Realm.runWithDefault(Realm.java:332) ~[na:na]
	at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine.run(PartRenderingEngine.java:997) ~[na:na]
	at org.eclipse.e4.ui.internal.workbench.E4Workbench.createAndRunUI(E4Workbench.java:138) ~[na:na]
	at org.eclipse.e4.ui.internal.workbench.swt.E4Application.start(E4Application.java:162) ~[na:na]
	at org.eclipse.equinox.internal.app.EclipseAppHandle.run(EclipseAppHandle.java:196) ~[na:na]
	at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.runApplication(EclipseAppLauncher.java:110) ~[na:na]
	at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.start(EclipseAppLauncher.java:79) ~[na:na]
	at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:354) ~[na:na]
	at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:181) ~[na:na]
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.7.0_07]
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57) ~[na:1.7.0_07]
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.7.0_07]
	at java.lang.reflect.Method.invoke(Method.java:601) ~[na:1.7.0_07]
	at org.eclipse.equinox.launcher.Main.invokeFramework(Main.java:636) ~[org.eclipse.equinox.launcher_1.3.0.v20130327-1440.jar:na]
	at org.eclipse.equinox.launcher.Main.basicRun(Main.java:591) ~[org.eclipse.equinox.launcher_1.3.0.v20130327-1440.jar:na]
	at org.eclipse.equinox.launcher.Main.run(Main.java:1450) ~[org.eclipse.equinox.launcher_1.3.0.v20130327-1440.jar:na]