Improving error message for invalid updates

Author: lostintangent

android/app/src/main/java/com/microsoft/codepush/react/CodePushPackage.java

@@ -246,7 +246,7 @@ public void downloadPackage(ReadableMap updatePackage, String expectedBundleFile
             String relativeBundlePath = CodePushUpdateUtils.findJSBundleInUpdateContents(newUpdateFolderPath, expectedBundleFileName);
 
             if (relativeBundlePath == null) {
-                throw new CodePushInvalidUpdateException("Update is invalid - no files with extension .bundle, .js or .jsbundle were found in the update package.");
+                throw new CodePushInvalidUpdateException("Update is invalid - A JS bundle file named \"" + expectedBundleFileName + "\" could not be found within the downloaded contents. Please check that you are releasing your CodePush updates using the exact same JS bundle file name that was shipped with your app's binary.");
             } else {
                 if (FileUtils.fileAtPathExists(newUpdateMetadataPath)) {
                     File metadataFileFromOldUpdate = new File(newUpdateMetadataPath);

ios/CodePush/CodePushPackage.m

@@ -207,7 +207,9 @@ + (void)downloadPackage:(NSDictionary *)updatePackage
                                                         if (relativeBundlePath) {
                                                             [mutableUpdatePackage setValue:relativeBundlePath forKey:RelativeBundlePathKey];
                                                         } else {
-                                                            error = [CodePushErrorUtils errorWithMessage:@"Update is invalid - no files with extension .jsbundle or .bundle were found in the update package."];
+                                                            NSString *errorMessage = [NSString stringWithFormat:@"Update is invalid - A JS bundle file named \"%@\" could not be found within the downloaded contents. Please check that you are releasing your CodePush updates using the exact same JS bundle file name that was shipped with your app's binary.", expectedBundleFileName];
+                                                            
+                                                            error = [CodePushErrorUtils errorWithMessage:errorMessage];
 
                                                             failCallback(error);
                                                             return;

package-mixins.js

@@ -27,8 +27,12 @@ module.exports = (NativeCodePush) => {
           const downloadedPackage = await NativeCodePush.downloadUpdate(this);
           reportStatusDownload && reportStatusDownload(this);
           return { ...downloadedPackage, ...local };
+        } catch (e) {
+          // Rethrow the error so that the caller of this method
+          // is aware of the issue (e.g. the update was invalid)
+          throw e;
         } finally {
-          downloadProgressSubscription && downloadProgressSubscription.remove();
+          downloadProgressSubscription && downloadProgressSubscription.remove(); 
         }
       },