Forward the error message

Signed-off-by: Dominik Henneke <dominik.henneke@sda-se.com>

plugins/catalog-backend/src/ingestion/processors/PlaceholderProcessor.test.ts

@@ -345,7 +345,7 @@ describe('PlaceholderProcessor', () => {
         },
       ),
     ).rejects.toThrow(
-      'Placeholder $text could not form a URL out of ./a/b/catalog-info.yaml and ../c/catalog-info.yaml',
+      'Placeholder $text could not form a URL out of ./a/b/catalog-info.yaml and ../c/catalog-info.yaml, TypeError: Invalid base URL: ./a/b/catalog-info.yaml',
     );
 
     expect(read).not.toBeCalled();

plugins/catalog-backend/src/ingestion/processors/PlaceholderProcessor.ts

@@ -216,13 +216,13 @@ function relativeUrl({
 
   try {
     return resolveUrl(value, baseUrl);
-  } catch (_) {
+  } catch (e) {
     // The only remaining case that isn't support is a relative file path that should be
     // resolved using a relative file location. Accessing local file paths can lead to
     // path traversal attacks and access to any file on the host system. Implementing this
     // would require additional security measures.
     throw new Error(
-      `Placeholder \$${key} could not form a URL out of ${baseUrl} and ${value}`,
+      `Placeholder \$${key} could not form a URL out of ${baseUrl} and ${value}, ${e}`,
     );
   }
 }