From e76acae44ca82c2aeaf5c7fa66df98a051198970 Mon Sep 17 00:00:00 2001
From: Christoph Rueger <chrisrueger@gmail.com>
Date: Thu, 23 Jan 2025 15:36:28 +0100
Subject: [PATCH] show error when fetching templates from Github

This shows "some" error in the UI when there are problems fetching from Github.
The error message also includes a hint to https://bnd.bndtools.org/instructions/connection-settings.html because sometimes you have a ~/.m2/settings.xml with some credentials which can lead to "Bad Credentials" http errors from the Github API, but before this fix you had no idea what was going on, because the UI was blank and the existance of ~/.m2/settings.xml is easily forgotton

Signed-off-by: Christoph Rueger <chrisrueger@gmail.com>
---
 .../shared/TemplateSelectionWizardPage.java       | 13 +++++++++++--
 .../src/org/bndtools/templating/jgit/Cache.java   | 15 +++++++++++++++
 .../src/org/bndtools/templating/jgit/GitHub.java  |  4 ++++
 3 files changed, 30 insertions(+), 2 deletions(-)

diff --git a/bndtools.core/src/org/bndtools/core/ui/wizards/shared/TemplateSelectionWizardPage.java b/bndtools.core/src/org/bndtools/core/ui/wizards/shared/TemplateSelectionWizardPage.java
index 02a58bde57..d1fcc5d1d1 100644
--- a/bndtools.core/src/org/bndtools/core/ui/wizards/shared/TemplateSelectionWizardPage.java
+++ b/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(() -> {
+									txtDescription.setText("Failed to load from template loader (" + name
+										+ ") See Error Log for stack trace: "
+										+ failure.getMessage());
+								});
+
 							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();
diff --git a/org.bndtools.templating.gitrepo/src/org/bndtools/templating/jgit/Cache.java b/org.bndtools.templating.gitrepo/src/org/bndtools/templating/jgit/Cache.java
index 1b01750e20..2da9d063f7 100644
--- a/org.bndtools.templating.gitrepo/src/org/bndtools/templating/jgit/Cache.java
+++ b/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.)");
+	}
+
 }
diff --git a/org.bndtools.templating.gitrepo/src/org/bndtools/templating/jgit/GitHub.java b/org.bndtools.templating.gitrepo/src/org/bndtools/templating/jgit/GitHub.java
index 873356fcf1..2904c6cd5d 100644
--- a/org.bndtools.templating.gitrepo/src/org/bndtools/templating/jgit/GitHub.java
+++ b/org.bndtools.templating.gitrepo/src/org/bndtools/templating/jgit/GitHub.java
@@ -1,5 +1,6 @@
 package org.bndtools.templating.jgit;
 
+import java.io.IOException;
 import java.net.URI;
 import java.util.Objects;
 import java.util.concurrent.Executor;
@@ -33,6 +34,9 @@ public Promise<GithubRepoDetailsDTO> loadRepoDetails(String repository) {
 			return new JSONCodec().dec()
 				.from(detailsDtoData)
 				.get(GithubRepoDetailsDTO.class);
+		})
+			.onFailure(t -> {
+				throw new IOException("Error fetching Github repo details: " + URL_PREFIX + repository, t);
 		});
 	}
 }