Fail fast when a model processor prerequisite is missing

bundles/org.eclipse.e4.ui.workbench/META-INF/MANIFEST.MF

@@ -1,7 +1,7 @@
 Manifest-Version: 1.0
 Bundle-ManifestVersion: 2
 Bundle-SymbolicName: org.eclipse.e4.ui.workbench;singleton:=true
-Bundle-Version: 1.18.300.qualifier
+Bundle-Version: 1.18.400.qualifier
 Bundle-Name: %pluginName
 Bundle-Vendor: %providerName
 Bundle-Localization: plugin

bundles/org.eclipse.e4.ui.workbench/src/org/eclipse/e4/ui/internal/workbench/ModelAssembler.java

@@ -690,7 +690,7 @@ private void runProcessor(IConfigurationElement ce) {
 				ContextInjectionFactory.invoke(o, Execute.class, context, localContext, null);
 			}
 		} catch (Exception e) {
-			warn("Could not run processor: {}", e); //$NON-NLS-1$
+			error("Could not run processor {}: {}", ce.getAttribute("class"), e); //$NON-NLS-1$//$NON-NLS-2$
 		}
 	}
 
@@ -731,7 +731,9 @@ private void runProcessor(IModelProcessorContribution processor) {
 				ContextInjectionFactory.invoke(o, Execute.class, context, localContext, null);
 			}
 		} catch (Exception e) {
-			warn("Could not run processor: {}", e); //$NON-NLS-1$
+			Class<?> processorClass = processor.getProcessorClass() != null ? processor.getProcessorClass()
+					: processor.getClass();
+			error("Could not run processor {}: {}", processorClass.getName(), e); //$NON-NLS-1$
 		}
 	}
 

bundles/org.eclipse.ui.workbench/eclipseui/org/eclipse/ui/internal/BindingToModelProcessor.java

@@ -52,7 +52,8 @@ public class BindingToModelProcessor implements IModelProcessorContribution {
 
 	// define dependencies to CommandToModelProcessor and ContextToModelProcessor to
 	// ensure these two IModelProcessorContributions are registered before this
-	// BindingToModelProcessor
+	// BindingToModelProcessor. Both fields are read in process(), removing them
+	// silently breaks that ordering.
 
 	@Reference
 	private CommandToModelProcessor commandToModelProcessor;
@@ -66,14 +67,10 @@ void process(final MApplication application, IEclipseContext context) {
 		gatherCommands(application.getCommands());
 		gatherTables(application.getBindingTables());
 
-		CommandManager commandManager = context.get(CommandManager.class);
-		if (commandManager == null) {
-			WorkbenchPlugin.log("Command manager was null in org.eclipse.ui.internal.BindingToModelProcessor"); //$NON-NLS-1$
-		}
-		ContextManager contextManager = context.get(ContextManager.class);
-		if (contextManager == null) {
-			WorkbenchPlugin.log("Context manager was null in org.eclipse.ui.internal.BindingToModelProcessor"); //$NON-NLS-1$
-		}
+		CommandManager commandManager = requirePrerequisite(context, CommandManager.class,
+				CommandToModelProcessor.class, commandToModelProcessor);
+		ContextManager contextManager = requirePrerequisite(context, ContextManager.class,
+				ContextToModelProcessor.class, contextToModelProcessor);
 		BindingManager bindingManager = new BindingManager(contextManager, commandManager);
 		context.set(BindingManager.class, bindingManager);
 		BindingPersistence persistence = new BindingPersistence(bindingManager, commandManager);
@@ -98,6 +95,25 @@ void process(final MApplication application, IEclipseContext context) {
 		keys.clear();
 	}
 
+	/**
+	 * Returns the value stored under the given key, failing with a message that
+	 * names the processor expected to have provided it. The provider instance is
+	 * the DS reference that orders this processor after that one.
+	 */
+	private static <T> T requirePrerequisite(IEclipseContext context, Class<T> key, Class<?> providerType,
+			Object provider) {
+		T value = context.get(key);
+		if (value == null || provider == null) {
+			String message = String.format(
+					"%s did not find %s in the application context. %s must run first; check that its @Reference in %s is still declared and that the OSGi component descriptors of this bundle are up to date.", //$NON-NLS-1$
+					BindingToModelProcessor.class.getName(), key.getName(), providerType.getName(),
+					BindingToModelProcessor.class.getSimpleName());
+			WorkbenchPlugin.log(message);
+			throw new IllegalStateException(message);
+		}
+		return value;
+	}
+
 	private void gatherTables(List<MBindingTable> bindingTables) {
 		for (MBindingTable table : bindingTables) {
 			tables.put(table.getBindingContext().getElementId(), table);