Improve error message when fetch fails (#310)

Author: bwateratmsft

package-lock.json

@@ -1,3 +1,7 @@
+## 0.4.1 - 14 October 2025
+### Fixed
+* Better error messages in the tree when errors occur. [#310](https://github.com/microsoft/vscode-docker-extensibility/pull/310)
+
 ## 0.4.0 - 6 October 2025
 ### Added
 * Package is now a combined CJS+ESM package, instead of just CJS. [#297](https://github.com/microsoft/vscode-docker-extensibility/pull/297)

packages/vscode-docker-registries/CHANGELOG.md

@@ -1,7 +1,7 @@
 {
     "name": "@microsoft/vscode-docker-registries",
     "author": "Microsoft Corporation",
-    "version": "0.4.0",
+    "version": "0.4.1",
     "description": "Extensibility model for contributing registry providers to the Container Tools extension for Visual Studio Code",
     "license": "See LICENSE in the project root for license information.",
     "repository": {

packages/vscode-docker-registries/package.json

@@ -24,10 +24,21 @@ export function getErrorTreeItem(error: unknown, parent: CommonRegistryItem | un
         } as RegistryConnectError];
     }
 
+    let message: string | undefined;
+    if (typeof error === 'string') {
+        message = error;
+    } else if (error instanceof Error && !!error.message) {
+        if (!!error.cause && error.cause instanceof Error && !!error.cause.message) {
+            message = `${error.message}: ${error.cause.message}`;
+        } else {
+            message = error.message;
+        }
+    }
+
     // Otherwise, return a generic error
     return [{
         parent: parent,
-        label: error instanceof Error ? error.message : vscode.l10n.t('Unknown error'),
+        label: message ?? vscode.l10n.t('Unknown error'),
         type: 'commonerror',
     }];
 }