Description Alexander Zakusylo 2019-07-08 07:31:10 EDT

RATs may continue to get triggered after disposing the context

We faced this issue in our RCP application when user drags an editor to another window and then closes the first window.

The root cause is that listeners added by EclipseContext#trackAccess may stay forever in child contexts.

I was able to find out a minimal reproducible snippet:

                IEclipseContext root = EclipseContextFactory.create("root");
		IEclipseContext oldParent = root.createChild("oldParent");
		IEclipseContext newParent = root.createChild("newParent");
		IEclipseContext leaf = oldParent.createChild("leaf");

		oldParent.runAndTrack(new RunAndTrack() {
			@Override
			public boolean changed(IEclipseContext context) {
				IEclipseContext activeLeaf = context.getActiveLeaf();
				System.err.println("oldParent's active leaf = " + activeLeaf);
				return true;
			}
		});

		leaf.activateBranch();
		leaf.setParent(newParent);


		oldParent.dispose();
		System.err.println("oldParent is disposed now !!");

		leaf.activateBranch(); // <---- THIS CALL TRIGGERS RAT IN DISPOSED oldParent


Wrapping the RAT code into RunAndTrack.runExternalCode fixes this snippet, but in our app RAT WorkbenchWindow.setup() is being triggered (WorkbenchWindow.java:724)

		RunAndTrack menuChangeManager = new RunAndTrack() {
		@Override
		public boolean changed(IEclipseContext context) {
			ExpressionInfo info = new ExpressionInfo();
			IEclipseContext leafContext = windowContext.getActiveLeaf();
                . . .