Workspace Templates: show error when fetching templates from Github

bndtools.core/src/bndtools/wizards/newworkspace/NewWorkspaceWizard.java

@@ -9,7 +9,10 @@
 import java.util.stream.Stream;
 
 import org.bndtools.core.ui.icons.Icons;
+import org.eclipse.core.runtime.IStatus;
+import org.eclipse.core.runtime.Status;
 import org.eclipse.core.runtime.jobs.Job;
+import org.eclipse.jface.dialogs.ErrorDialog;
 import org.eclipse.jface.viewers.ArrayContentProvider;
 import org.eclipse.jface.viewers.CheckboxTableViewer;
 import org.eclipse.jface.viewers.ColumnLabelProvider;
@@ -49,6 +52,7 @@
 import aQute.bnd.wstemplates.FragmentTemplateEngine;
 import aQute.bnd.wstemplates.FragmentTemplateEngine.TemplateInfo;
 import aQute.bnd.wstemplates.FragmentTemplateEngine.TemplateUpdater;
+import bndtools.Plugin;
 import bndtools.central.Central;
 import bndtools.util.ui.UI;
 
@@ -86,6 +90,19 @@ public NewWorkspaceWizard() throws Exception {
 					ui.write(() -> model.templates = templates.getAvailableTemplates());
 				} catch (Exception e) {
 					log.error("failed to read default index {}", e, e);
+
+					Display.getDefault()
+						.asyncExec(() -> {
+
+							IStatus status = new Status(IStatus.ERROR, Plugin.PLUGIN_ID, "failed to read default index",
+								e);
+							ErrorDialog.openError(getShell(), "Error", "An error occurred", status);
+						});
+
+					Plugin.getDefault()
+						.getLog()
+						.log(new Status(IStatus.ERROR, Plugin.PLUGIN_ID, 0,
+							"failed to read default index " + DEFAULT_INDEX, e));
 				}
 			});
 			job.schedule();

bndtools.core/src/org/bndtools/core/ui/wizards/shared/TemplateSelectionWizardPage.java

@@ -62,8 +62,8 @@
 import org.osgi.service.component.ComponentConstants;
 import org.osgi.util.promise.Promise;
 
-import aQute.bnd.osgi.Processor;
 import aQute.bnd.exceptions.Exceptions;
+import aQute.bnd.osgi.Processor;
 import aQute.lib.io.IO;
 import aQute.libg.tuple.Pair;
 import bndtools.Plugin;
@@ -294,11 +294,20 @@ public void run(IProgressMonitor progress) throws InvocationTargetException {
 					try {
 						Throwable failure = namedPromise.getSecond()
 							.getFailure();
-						if (failure != null)
+						if (failure != null) {
+
+							shell.getDisplay()
+								.asyncExec(() -> {
+									IStatus status = new Status(IStatus.ERROR, Plugin.PLUGIN_ID,
+										"Error loading templates", failure);
+									ErrorDialog.openError(shell, "Error", "An error occurred", status);
+								});
+
 							Plugin.getDefault()
 								.getLog()
 								.log(new Status(IStatus.ERROR, Plugin.PLUGIN_ID, 0,
 									"Failed to load from template loader: " + name, failure));
+						}
 						else {
 							Collection<Template> loadedTemplates = namedPromise.getSecond()
 								.getValue();

org.bndtools.templating.gitrepo/src/org/bndtools/templating/jgit/Cache.java

@@ -28,6 +28,11 @@ public byte[] download(URI uri) throws Exception {
 				TaggedData td = client.connectTagged(uri.toURL());
 				if (td == null || td.isNotFound())
 					throw new FileNotFoundException("Not found");
+
+				if (td.getInputStream() == null) {
+					throwNoResponseError(td);
+				}
+
 				data = IO.read(td.getInputStream());
 				if (td.getTag() != null)
 					cache.put(uri, new Pair<>(td.getTag(), data));
@@ -41,6 +46,11 @@ public byte[] download(URI uri) throws Exception {
 					data = cachedTag.getSecond();
 				} else {
 					// changed
+
+					if (td.getInputStream() == null) {
+						throwNoResponseError(td);
+					}
+
 					data = IO.read(td.getInputStream());
 					if (td.getTag() == null) {
 						// server now not giving an etag -> remove from cache
@@ -59,4 +69,9 @@ public byte[] download(URI uri) throws Exception {
 		}
 	}
 
+	private void throwNoResponseError(TaggedData td) throws IOException {
+		throw new IOException("Error (HTTP " + td.getResponseCode() + ") - no response: " + td
+			+ " (Check https://bnd.bndtools.org/instructions/connection-settings.html in case of connection or authentication errors.)");
+	}
+
 }