Dart 2 support

[rmathias86]

Hey there,

Are there any expectations to convert the code for dart2? Or to have a specific branch of it.
I've tested it with Flutter (Dart 1) and RabbitMQ and it's working nicely. But I do think to use dart2 instead.

I would like to help if possible.

Cheers,

[achilleasa]

Hi there.

I think that the code should work as-is with dart2. In fact, I just tried running the test suite against 2.0.0-dev.60.0 and all tests seem to pass. Let me know if you encounter any issues using dart 2.x

[rmathias86]

Hey,

Using Flutter/Dart from flutter master channel, Dart version 2.0.0-dev.60.0.flutter-a5e41681e5

compiler message: file:///Users/rodrigomathias/development/flutter/.pub-cache/git/dart_amqp-7a2c7fd2278dfabf4138fb196de5312d1ebcfc80/lib/src/client/impl/channel_impl.dart:417:10: Error: The return type of the method '_ChannelImpl::close' is dart.async::Future<dynamic>, which does not match the return type of the overridden method (dart.async::Future<dart_amqp.client::Channel>). compiler message: Change to a subtype of dart.async::Future<dart_amqp.client::Channel>. compiler message: Future close() => _close(replyCode : ErrorType.SUCCESS, replyText : "Normal shutdown"); compiler message: ^ compiler message: file:///Users/rodrigomathias/development/flutter/.pub-cache/git/dart_amqp-7a2c7fd2278dfabf4138fb196de5312d1ebcfc80/lib/src/client/channel.dart:11:19: Context: This is the overriden method ('close'). compiler message: Future<Channel> close(); compiler message: ^

Using Flutter/Dart from beta channel, Dart version 2.0.0-dev.54.0.flutter-46ab040e58

type 'Future<dynamic>' is not a subtype of type 'Future<Queue>' #0 _ChannelImpl.queue (file:///Users/rodrigomathias/development/flutter/.pub-cache/git/dart_amqp-7a2c7fd2278dfabf4138fb196de5312d1ebcfc80/lib/src/client/impl/channel_impl.dart:432:24) #1 _MyHomePageState.initState.<anonymous closure> (file:///Users/rodrigomathias/Work/temp/rabbittest/lib/main.dart:48:44) #2 _RootZone.runUnary (dart:async/zone.dart:1381:54) #3 _FutureListener.handleValue (dart:async/future_impl.dart:129:18) #4 Future._propagateToListeners.handleValueCallback (dart:async/future_impl.dart:633:45) #5 Future._propagateToListeners (dart:async/future_impl.dart:662:32) #6 Future._completeWithValue (dart:async/future_impl.dart:477:5) #7 Future._asyncComplete.<anonymous closure> (dart:async/future_impl.dart:507:7) #8 _microtaskLoop (dart:async/schedule_microtask.dart:41:21) #9 _startMicrotaskLoop (dart:async/schedule_microtask.dart<…>

Code:

ConnectionSettings settings = new ConnectionSettings(
host : "baboon.rmq.cloudamqp.com",
virtualHost: "lahubkks",
authProvider: new AmqPlainAuthenticator("lahubkks","nroDZ6yuho7zgQNRnCxe5r1PzxfW2XEG")
);
Client client = new Client(settings: settings);
client
.channel()
.then((Channel channel) => channel.queue("hello"))
.then((Queue queue) => queue.consume())
.then((Consumer consumer) => consumer.listen((AmqpMessage message) {
print(" [x] Received string: ${message.payloadAsString}");
}));

Using flutter run --no-preview-dart-2 (to not use dart 2 in flutter) it works perfectly.

Thanks in advanced for any idea what's going on.

[rmathias86]

I've found this thread regarding --preview-dart-2
https://groups.google.com/a/dartlang.org/forum/#!topic/announce/D2mju9oXmUg

This may cause some breakages due to stricter Dart type enforcement.

[achilleasa]

Thanks for bringing this to my attention. I think I know why the compiler complains. I will run everything through dartalyzer and push an updated package later today.

[achilleasa]

In the meantime you can try applying this fix manually to your local package:

diff --git a/lib/src/client/impl/channel_impl.dart b/lib/src/client/impl/channel_impl.dart
index 9686c1f..f9b4c47 100644
--- a/lib/src/client/impl/channel_impl.dart
+++ b/lib/src/client/impl/channel_impl.dart
@@ -410,11 +410,11 @@ class _ChannelImpl implements Channel {
   }

   /**
-   * Close the channel and return a [Future] to be completed when the channel is closed.
+   * Close the channel and return a [Future<Channel>] to be completed when the channel is closed.
    *
    * After closing the channel any attempt to send a message over it will cause a [StateError]
    */
-  Future close() => _close(replyCode : ErrorType.SUCCESS, replyText : "Normal shutdown");
+  Future<Channel> close() => _close(replyCode : ErrorType.SUCCESS, replyText : "Normal shutdown");

[rmathias86]

@achilleasa, thanks for your efforts

I ran dartanalyzer command with --no-implicit-casts (flutter uses strong mode) and got these errors now

error • A value of type 'Consumer' can't be assigned to a variable of type '_ConsumerImpl' at lib/src/client/impl/channel_impl.dart:264:50 • invalid_assignment
error • The argument type 'DecodedMessage' can't be assigned to the parameter type 'DecodedMessageImpl' at lib/src/client/impl/channel_impl.dart:287:26 • argument_type_not_assignable
error • The return type 'Future' isn't a 'Future', as defined by the method 'queue' at lib/src/client/impl/channel_impl.dart:432:12 • return_of_invalid_type
error • The return type 'Future' isn't a 'Future', as defined by the method 'privateQueue' at lib/src/client/impl/channel_impl.dart:448:12 • return_of_invalid_type
error • The return type 'Future' isn't a 'Future', as defined by the method 'exchange' at lib/src/client/impl/channel_impl.dart:471:12 • return_of_invalid_type
error • The return type 'StreamSubscription' isn't a 'StreamSubscription', as defined by the method 'basicReturnListener' at lib/src/client/impl/channel_impl.dart:474:162 • return_of_invalid_type
error • The argument type '(BasicReturnMessage) → void' can't be assigned to the parameter type '(dynamic) → void' at lib/src/client/impl/channel_impl.dart:474:195 • argument_type_not_assignable
error • The return type 'Future' isn't a 'Future', as defined by the method 'qos' at lib/src/client/impl/channel_impl.dart:490:12 • return_of_invalid_type
error • The return type 'Future' isn't a 'Future', as defined by the method 'select' at lib/src/client/impl/channel_impl.dart:505:12 • return_of_invalid_type
error • The return type 'Future' isn't a 'Future', as defined by the method 'commit' at lib/src/client/impl/channel_impl.dart:512:12 • return_of_invalid_type
error • The return type 'Future' isn't a 'Future', as defined by the method 'rollback' at lib/src/client/impl/channel_impl.dart:519:12 • return_of_invalid_type
error • The return type 'Future' isn't a 'Future', as defined by the method 'flow' at lib/src/client/impl/channel_impl.dart:528:12 • return_of_invalid_type
error • The return type 'Future' isn't a 'Future', as defined by the method 'recover' at lib/src/client/impl/channel_impl.dart:537:12 • return_of_invalid_type
error • Type 'dynamic' of the switch expression isn't assignable to the type 'Type' of case expressions at lib/src/client/impl/client_impl.dart:176:13 • switch_expression_not_assignable
error • The return type 'StreamSubscription' isn't a 'StreamSubscription', as defined by the method 'errorListener' at lib/src/client/impl/client_impl.dart:282:136 • return_of_invalid_type
error • The argument type '(Exception) → void' can't be assigned to the parameter type '(dynamic) → void' at lib/src/client/impl/client_impl.dart:282:157 • argument_type_not_assignable
error • The return type 'StreamSubscription' isn't a 'StreamSubscription', as defined by the method 'listen' at lib/src/client/impl/consumer_impl.dart:13:133 • return_of_invalid_type
error • The argument type '(AmqpMessage) → void' can't be assigned to the parameter type '(dynamic) → void' at lib/src/client/impl/consumer_impl.dart:13:159 • argument_type_not_assignable
error • The return type 'Future' isn't a 'Future', as defined by the method 'cancel' at lib/src/client/impl/consumer_impl.dart:23:12 • return_of_invalid_type
error • The return type 'Future' isn't a 'Future', as defined by the method 'delete' at lib/src/client/impl/exchange_impl.dart:21:12 • return_of_invalid_type
error • The return type 'Future' isn't a 'Future', as defined by the method 'delete' at lib/src/client/impl/queue_impl.dart:27:12 • return_of_invalid_type
error • The return type 'Future' isn't a 'Future', as defined by the method 'purge' at lib/src/client/impl/queue_impl.dart:38:12 • return_of_invalid_type
error • The return type 'Future' isn't a 'Future', as defined by the method 'bind' at lib/src/client/impl/queue_impl.dart:63:12 • return_of_invalid_type
error • The return type 'Future' isn't a 'Future', as defined by the method 'unbind' at lib/src/client/impl/queue_impl.dart:87:12 • return_of_invalid_type
error • The return type 'Future' isn't a 'Future', as defined by the method 'consume' at lib/src/client/impl/queue_impl.dart:119:12 • return_of_invalid_type
error • The return type 'dynamic' isn't a 'Map', as defined by the method 'payloadAsJson' at lib/src/protocol/frame/impl/decoded_message_impl.dart:52:12 • return_of_invalid_type
error • The argument type 'Endianness' can't be assigned to the parameter type 'Endian' at lib/src/protocol/stream/type_decoder.dart:19:42 • argument_type_not_assignable
error • The argument type 'Endianness' can't be assigned to the parameter type 'Endian' at lib/src/protocol/stream/type_decoder.dart:26:41 • argument_type_not_assignable
error • The argument type 'Endianness' can't be assigned to the parameter type 'Endian' at lib/src/protocol/stream/type_decoder.dart:33:42 • argument_type_not_assignable
error • The argument type 'Endianness' can't be assigned to the parameter type 'Endian' at lib/src/protocol/stream/type_decoder.dart:40:41 • argument_type_not_assignable
error • The argument type 'Endianness' can't be assigned to the parameter type 'Endian' at lib/src/protocol/stream/type_decoder.dart:47:42 • argument_type_not_assignable
error • The argument type 'Endianness' can't be assigned to the parameter type 'Endian' at lib/src/protocol/stream/type_decoder.dart:54:41 • argument_type_not_assignable
error • The argument type 'Endianness' can't be assigned to the parameter type 'Endian' at lib/src/protocol/stream/type_decoder.dart:61:46 • argument_type_not_assignable
error • The argument type 'Endianness' can't be assigned to the parameter type 'Endian' at lib/src/protocol/stream/type_decoder.dart:68:46 • argument_type_not_assignable
error • The argument type 'Endianness' can't be assigned to the parameter type 'Endian' at lib/src/protocol/stream/type_encoder.dart:23:54 • argument_type_not_assignable
error • The argument type 'Endianness' can't be assigned to the parameter type 'Endian' at lib/src/protocol/stream/type_encoder.dart:29:54 • argument_type_not_assignable
error • The argument type 'Endianness' can't be assigned to the parameter type 'Endian' at lib/src/protocol/stream/type_encoder.dart:35:54 • argument_type_not_assignable
error • The argument type 'Endianness' can't be assigned to the parameter type 'Endian' at lib/src/protocol/stream/type_encoder.dart:47:55 • argument_type_not_assignable
error • The argument type 'Endianness' can't be assigned to the parameter type 'Endian' at lib/src/protocol/stream/type_encoder.dart:53:55 • argument_type_not_assignable
error • The argument type 'Endianness' can't be assigned to the parameter type 'Endian' at lib/src/protocol/stream/type_encoder.dart:59:55 • argument_type_not_assignable
error • The argument type 'Endianness' can't be assigned to the parameter type 'Endian' at lib/src/protocol/stream/type_encoder.dart:65:56 • argument_type_not_assignable
error • The argument type 'Endianness' can't be assigned to the parameter type 'Endian' at lib/src/protocol/stream/type_encoder.dart:71:56 • argument_type_not_assignable
error • The argument type 'List' can't be assigned to the parameter type 'Uint8List' at lib/src/protocol/stream/type_encoder.dart:108:21 • argument_type_not_assignable
error • The argument type 'List' can't be assigned to the parameter type 'Uint8List' at lib/src/protocol/stream/type_encoder.dart:121:21 • argument_type_not_assignable
error • The argument type 'Map' can't be assigned to the parameter type 'Map<String, Object>' at lib/src/protocol/stream/type_encoder.dart:174:23 • argument_type_not_as

[rmathias86]

Hey,

I made some changes on my forked repo and it's working nicely, for now.
https://github.com/rmathias86/dart_amqp/commit/6fa0acb8a0b1e4210f8fe54ecfe70c8733d5eb2d#diff-9108cd2274bb34b410042e7c8bebae1d

[achilleasa]

Ah, thanks for figuring out a fix. I totally missed that as I am not currently using Flutter. Are your changes (Endian, JSON and UTF8) backwards compatible with dart 1.x?

Actually, I could merge #14 which has some dartanalyzer fixes (and also updates .travis.yaml to run dartanalyzer) and you can open a new PR with your additional fixes (also update .travis.yaml to run with --no-implicit-casts).

[rmathias86]

@hi @achilleasa,

So, I didn't test with dart 1.x yet. Even dart-analyzer was complaining about Endian, JSON and UTF8, I think these changes are not necessary, actually. I will test it again using only < TYPE > changes., which I believe should be backward compatible with dart 1.x, right?

[achilleasa]

I just merged #14 which fixes the type errors reported by dartanalyzer (but not the ones reported when running with --no-implicit-casts). As I mention above, I have updated the .travis.yaml file to run tests/dartanalyzer against both dart 1.x and 2.x so if you rebase your extra type changes on top of HEAD and add the --no-implicit-casts flag to dartanalyzer the CI should check if everything is backwards compatible with dart 1.

[rmathias86]

@Hey @achilleasa,

I can confirm with the #15 that only these changes are enough to run dart_amqp with current flutter SDK, either using beta or master channel. I don't have enough experience with the dart language to decide what is better about other changes. 👍

Many thanks, this plugin is going to be a key to achieve the success of our project in our company.

[achilleasa]

I have merged #15 and pushed an updated package so I am closing this issue.

Thanks for your PR and please do open more issues if you encounter other dart2 compatibility issues in the future.