Configuration parsing error when reusing an input in a composite solid.

If I have understood composite solids correctly, then I would expect to be able to run the following example where I reuse the arg to calculate_result in two of the inner solids. However, I get an error:

dagster.core.errors.DagsterInvalidConfigError: Pipeline “my_pipeline” config errors: Error 1: Missing required field “calculate_result” at path root:solids Available Fields: “[‘calculate_result’, ‘noop’]”.

from dagster import execute_pipeline, pipeline, lambda_solid, composite_solid


@lambda_solid
def noop(arg):
    return arg


@lambda_solid
def add_one(arg):
    return arg + 1


@lambda_solid
def adder(first, second):
    return first + second


@composite_solid
def calculate_result(arg):
    left = add_one.alias('add_one_left')(arg)
    right = add_one.alias('add_one_right')(arg)
    return adder(left, right)


@pipeline
def my_pipeline():
    return calculate_result(noop())


if __name__ == '__main__':
    execute_pipeline(
        my_pipeline,
        environment_dict={
            'solids': {
                'noop': {'inputs': {'arg': {'value': 1}}},
                # 'calculate_result': {'solids': {'add_one_left': {'inputs': {'arg': {'value': 10}}}}},
            }
        }
    )

If I uncomment the line in the environment_dict to fill the value for one of the solids inside, then the pipeline will run. Alternatively, if I change calculate_sum and my_pipeline so that I pass the same argument twice to calculate_sum then the pipeline will run:

@composite_solid
def calculate_result(arg1, arg2):
    left = add_one.alias('add_one_left')(arg1)
    right = add_one.alias('add_one_right')(arg2)
    return adder(left, right)


@pipeline
def my_pipeline():
    a = noop()
    return calculate_result(a, a)

[alangenfeld]

https://dagster.phacility.com/D584

[jack-pace]

Thanks, and yes, this is another real-world use case 😄