gistfile1.txt

@solid
def upstream_returning_nothing() -> Nothing:
    pass

@solid
def upstream_returning_string() -> str:
    return "something else"

@solid(
    input_defs=[InputDefinition("start", Nothing),
                InputDefinition("bar", String)]
)
def downstream_consuming_string(bar: str):
    pass


@pipeline
def nothing_dependency_pipeline():
    real_string = upstream_returning_string()
    downstream_consuming_string(upstream_returning_nothing(), real_string)

execute_pipeline(nothing_dependency_pipeline)

from dagster import (
    composite_solid,
    pipeline,
    solid,
    InputDefinition,
    Nothing,
    String,
    execute_pipeline,
)


@solid
def upstream_returning_nothing() -> Nothing:
    pass


@composite_solid
def upstream_composite_returning_nothing() -> Nothing:
    return upstream_returning_nothing()


@solid
def upstream_returning_string() -> str:
    return "something else"


@solid(input_defs=[InputDefinition("start", Nothing), InputDefinition("bar", String)])
def downstream_consuming_string(bar: str):
    pass


@composite_solid(input_defs=[InputDefinition("bar", String), InputDefinition("start", Nothing)])
def downstream_composite(bar: str, start: Nothing):
    downstream_consuming_string(bar, start=start)


@pipeline
def nothing_dependency_pipeline():
    real_string = upstream_returning_string()
    downstream_composite(real_string, start=upstream_composite_returning_nothing())


execute_pipeline(nothing_dependency_pipeline)