Description Pierre-Charles David 2016-11-27 08:58:09 EST

Created attachment 265602 [details]
Sample file to reproduce the bug

Steps to reproduce:
1. Import the projects in the attached zip.
2. Go to "Window > Preferences > Plug-in Development > Target Platforms", select the "sample" target from the workspace and validate ("OK").
3. Close the "tp" project (where the "sample.target" is defined).
4. Restart Eclipse.
5. Go to "Window > Preferences > Plug-in Development > Target Platforms". No target is set; click "Apply" and "OK".
6. Open the VSM in vsm/sample.odesign and go to single node mapping's workspace image style
7. In the style description tab of the properties view, select the "..." button to browse the images => NPE in the error log.

java.lang.NullPointerException
	at org.eclipse.sirius.editor.tools.internal.presentation.WorkspaceAndPluginsResourceDialog$WorkbenchProxyObject.getChildren(WorkspaceAndPluginsResourceDialog.java:256)
	at org.eclipse.sirius.editor.tools.internal.presentation.WorkspaceAndPluginsResourceDialog$CustomWorkbenchAdapter.getChildren(WorkspaceAndPluginsResourceDialog.java:396)
	at org.eclipse.ui.model.BaseWorkbenchContentProvider.getChildren(BaseWorkbenchContentProvider.java:60)
	at org.eclipse.sirius.editor.tools.internal.presentation.WorkspaceAndPluginsResourceDialog$DeferredWorkbenchContentProvider.getChildren(WorkspaceAndPluginsResourceDialog.java:375)
	at org.eclipse.ui.model.BaseWorkbenchContentProvider.getElements(BaseWorkbenchContentProvider.java:67)
	at org.eclipse.ui.dialogs.ElementTreeSelectionDialog.evaluateIfTreeEmpty(ElementTreeSelectionDialog.java:384)
	at org.eclipse.ui.dialogs.ElementTreeSelectionDialog.open(ElementTreeSelectionDialog.java:235)
	at org.eclipse.sirius.editor.tools.internal.presentation.WorkspaceAndPluginsResourceDialog.openDialogForImages(WorkspaceAndPluginsResourceDialog.java:139)
	at org.eclipse.sirius.diagram.editor.properties.sections.style.workspaceimagedescription.WorkspaceImageDescriptionWorkspacePathPropertySection$1.widgetSelected(WorkspaceImageDescriptionWorkspacePathPropertySection.java:119)

Sometimes, some or all of steps 2 to 5 are not needed, and simply opening the VSM and trying to browse the image triggers the NPE. I'm not sure what are the exact underlying conditions needed, but anyway, the code in WorkspaceAndPluginsResourceDialog is not robust to the case where ITargetPlatformService.getWorkspaceTargetHandle() returns null (which is a valid return value as described in its Javadoc).