NPE when changing Eclipse theme about eclipse.platform.ui

[jonahgraham]

Also fails with SDK for M2 (I20220428-1800) and with the 4.23 release version.

This is a regression in 4.23 compared to 4.22 and seems to be related to the change that uses this dialog (in 4.23):

vs this one in 4.22:

Hopefully someone reading this recognizes this change and knows where to direct this bug.

[lshanmug]

The dialog was changed via bug https://bugs.eclipse.org/bugs/show_bug.cgi?id=577476.
Adding @BeckerWdf

[BeckerWdf]

The error happens when the preference dialog is closed:

	@Override
	public boolean close() {
		if (showViewHandler != null) {
			IHandlerService service = PlatformUI.getWorkbench().getService(IHandlerService.class);
			service.deactivateHandler(showViewHandler);
			showViewHandler.getHandler().dispose();
			showViewHandler = null;
		}
...
	}

"service" is null in this case.
The cause seems to be that the restart is triggered while the dialog is open. Before the restart was triggered after the dialog was closed. So how should we fix this?
a) First close the dialog and then trigger the restart
b) Simply fix this NPE?

[laeubi]

What about asyncExec the restart? This should first close the dialog and then perform the restart...

[laeubi]

By the way regardless of the fix it might be good to check for null service return and give a better error message then running into NPE if the service is mandatory.

[BeckerWdf]

By the way regardless of the fix it might be good to check for null service return and give a better error message then running into NPE if the service is mandatory.

But that would be another fix in another issue.