Deadlock in AsyncDataloader with latest async versions #5463
Description
Describe the bug
Deadlock occurs when executing GraphQL queries with association loading using AsyncDataloader with the async gem after v2.28.1:
Relevant changes: socketry/async@v2.28.1...v2.29.0
Likely key change: socketry/async@cf7fce1
Versions
graphql 2.5.14
Roda 3.89.0
Falcon 0.52.4
async 2.34.0
sequel 5.98.0
GraphQL schema
class Gql::Types::Foo < GraphQL::Schema::Object
field :id, ID, null: false
field :name, String, null: false
field :bar_models, [Gql::Types::Bar], null: false
def bar_models
dataloader.with(Sources::RecordsByForeignKey, ::BarModel, :foo_model_id).load(object.id)
end
end
class Gql::Types::Bar < GraphQL::Schema::Object
field :id, ID, null: false
field :name, String, null: false
field :foo_model, Gql::Types::Foo, null: false
def foo_model
dataloader.with(Sources::RecordById, ::FooModel).load(object.foo_model_id)
end
end
class AppSchema < GraphQL::Schema
query Gql::Types::Query
use GraphQL::Dataloader::AsyncDataloader
end
GraphQL query
{
getAllFoos {
id
name
barModels { id name }
}
getAllBars {
id
name
fooModel { id name }
}
}
(no response - server deadlocks)
Steps to reproduce
Clone this demo repo and run it using the steps provided in the README:
https://github.com/iyotov-havelock/async-dataloader-issue
Expected behavior
Query returns all FooModels with their associated BarModels, and all BarModels with their associated FooModel. That's the case when using GraphQL::Dataloader, but not when using GraphQL::Dataloader::AsyncDataloader
Actual behavior
Server deadlocks during dataloader execution
fatal: No live threads left. Deadlock?
1 threads, 1 sleeps current:0x00005c4ab8f61890 main thread:0x00005c4ab8f61890
* #<Thread:0x000071ad9736a6d0 sleep_forever>
→ /gems/async-2.34.0/lib/async/promise.rb:89 in 'Thread::ConditionVariable#wait'
/gems/async-2.34.0/lib/async/promise.rb:89 in 'block in Async::Promise#wait'
/gems/async-2.34.0/lib/async/task.rb:258 in 'Async::Task#wait'
/gems/async-2.34.0/lib/kernel/sync.rb:28 in 'Kernel#Sync'
/gems/graphql-2.5.14/lib/graphql/dataloader/async_dataloader.rb:34 in 'block in GraphQL::Dataloader::AsyncDataloader#run'
Additional context
This looks like a compatibility issue between AsyncDataloader and async gem versions after v2.28.1
Relevant changes: socketry/async@v2.28.1...v2.29.0
Likely key change: socketry/async@cf7fce1