Fix: JSON parsing in backend_srv (#45598)

* fix(plugins/state): console log errors during install / uninstall

* fix(backend_srv): catch JSON parse errors

Sometimes it can happen that a backend API responses says that it's
returning with a JSON content-type, however it actually returns an invalid
JSON (e.g. an empty body) - in which case the backendSrv() request errors out.

public/app/core/utils/fetch.ts

@@ -105,7 +105,12 @@ export async function parseResponseBody<T>(
         return response.blob() as any;
 
       case 'json':
-        return response.json();
+        try {
+          return await response.json();
+        } catch (err) {
+          console.warn(`${response.url} returned an invalid JSON -`, err);
+          return {} as unknown as T;
+        }
 
       case 'text':
         return response.text() as any;

public/app/features/plugins/admin/state/actions.ts

@@ -73,6 +73,8 @@ export const install = createAsyncThunk(
 
       return { id, changes } as Update<CatalogPlugin>;
     } catch (e) {
+      console.error(e);
+
       return thunkApi.rejectWithValue('Unknown error.');
     }
   }
@@ -90,6 +92,8 @@ export const uninstall = createAsyncThunk(`${STATE_PREFIX}/uninstall`, async (id
       changes: { isInstalled: false, installedVersion: undefined },
     } as Update<CatalogPlugin>;
   } catch (e) {
+    console.error(e);
+
     return thunkApi.rejectWithValue('Unknown error.');
   }
 });