custom library-level exceptions

[micimize]

As pointed out in #177

we could solve this by creating our own kind of exceptions so that we can handle them cleaner internally.

It would also make it easier / possible for users to have different logic for different errors, i.e. ignore network related issues when using the cache.

Worth noting that without something like #201, it will be easy for a user making heavy use of the offline queue to shoot themselves in the foot by pretending mutations succeeded when they didn't and will never run again.

[micimize]

@mainawycliffe @HofmannZ I'm working on this right now, and currently looking at wrapping our graphql errors in a container similar to ApolloError.

Here's the general idea so far:

// in graphql/lib/src/exceptions/exceptions.dart
class OperationException implements Exception {
  List<GraphQLError> graphqlErrors = [];

  // generalize to include cache error, etc
  ClientException clientException; 
}


// in graphql/lib/src/core/query_result.dart
class QueryResult {
  // ...

  // in place of List<GraphQLError> errors;
  OperationException exception;
  /// Whether the response includes any graphql errors
  bool get hasErrors => !(exception == null);
 
  /// Whether the response includes any graphql errors
  bool get hasGraphqlErrors => exception?.graphqlErrors?.isNotEmpty ?? false;
 
  /// graphql errors in the exception, if any
  List<GraphQLError> get graphqlErrors => exception?.graphqlErrors;

  // ...
}

decisions / trade-offs:

• dart makes a semantic distinction between errors and exceptions - what we're dealing with on the client are mostly exceptions as they are meant to be handed rather than avoided.
• I don't think having all these *Errors methods is good - need to come up with a better api for handling multi-source errors. Maybe the thing to do is to not obscure the exception at all, replace hasError with hasException, and just let the user handle it like apollo does.

[micimize]

closed by #393

[HofmannZ]

🎉 This issue has been resolved in version 3.0.0-beta.1 🎉

The release is available on GitHub release

Your semantic-release bot 📦🚀

[HofmannZ]

🎉 This issue has been resolved in version 3.0.0 🎉

The release is available on GitHub release

Your semantic-release bot 📦🚀