Cached data is not available on the QueryResult when there is a network error.

[jifalops]

Describe the bug
Cached data is not available on the QueryResult when there is a network error.

To Reproduce
Steps to reproduce the behavior:

1. Set-up

GraphQLProvider(
      client: ValueNotifier<GraphQLClient>(
        GraphQLClient(
          cache: OptimisticCache(dataIdFromObject: _idFromObject),
          link: myLink,
        ),
      ),
      child: CacheProvider(
        child: MaterialApp(
  ...

2. Run a query and get the results.

class MyQuery extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Query(
      options: QueryOptions(
        // query is of a type generated by the `artemis` package
        documentNode: query.document,
      ),
      builder: (
        QueryResult result, {
        Future<QueryResult> Function() refetch,
        FetchMore fetchMore,
      }) {
        if (result.hasException) {
          return Text('${result.exception}');
        } else if (result.loading) {
          return Center(child: CircularProgressIndicator());
        }

        final items = query.parse(result.data);

        return Column(
          children: [
            ...items.map((item) => ListTile(
                  title: Text(item.name),
                  subtitle: Text('${item.typeName} ${item.id}'),
                ))
          ],
        );
      },
    );
  }
}

3. Enable airplane mode on the device
4. Press home and open another app (so the cache write is triggered)
5. Restart the app (hot restart). The result is now the network error and no cached data is available.

Expected behavior
Enabling airplane mode and hot-restarting the app should allow it to return the cached results.

Desktop (please complete the following information):

• OS: Ubuntu 20.04

Smartphone (please complete the following information):

• Device: Android emulator API 29

Additional context
Flutter beta 1.21.0-9.2.pre

[micimize]

Can you try this with 4.0.0-alpha.5?

[micimize]

This is outdated / likely solved by the cache rework 4.0.0-beta.1 (#648). Also this may just be because of the hot restart.

Please make a reproduction that doesn't involve live reload for testing

[micimize]

looked at this again and added a mechanism for carrying forward errors in #754

[jifalops]

i actually solved it with an HTTP link that caches queries. I think that is what's right for my use case.

[micimize]

Closed by #754