[BUG] Accessing attributes fails on complex types

[architrathore]

Describe the bug

As per Accessing Attributes documentation, accessing attributes on promises is supported in workflows.
This works for simple types like str or int, but fails during workflow compilation for complex types such as accessing inner dataclass on a nested dataclasses.

Expected behavior

Accessing attributes should work for all types, not just primitive ones.

Additional context to reproduce

• flytekit version==1.11.0

from __future__ import annotations

from dataclasses import dataclass

from flytekit import task, workflow
from mashumaro.mixins.json import DataClassJSONMixin


@dataclass
class Fruit(DataClassJSONMixin):
    name: str


@dataclass
class NestedFruit(DataClassJSONMixin):
    sub_fruit: Fruit
    name: str


@task
def dataclass_task() -> Fruit:
    return Fruit(name="banana")


@task
def dataclass_task_nested() -> NestedFruit:
    return NestedFruit(sub_fruit=Fruit(name="banana"), name="nested_name")


@task
def print_message(message: str):
    print(message)
    return


@task
def print_message_fruit(fruit_instance: Fruit):
    print(fruit_instance.name)
    print(fruit_instance)
    return


@task
def print_message_nested(nested_fruit: NestedFruit):
    print(nested_fruit.sub_fruit.name)
    print(nested_fruit.name)
    return


@workflow
def dataclass_wf():
    fruit_instance = dataclass_task()
    nested_fruit_instance = dataclass_task_nested()

    # ✅ accessing attribute of type=str 
    print_message(message=fruit_instance.name)
    # ✅ non attribute access 
    print_message_nested(nested_fruit=nested_fruit_instance)
    # ✅ accessing attribute of type=str on a nested dataclass
    print_message(message=nested_fruit_instance.sub_fruit.name)
    # ❌ accessing attribute of type=dataclass
    print_message_fruit(fruit_instance=nested_fruit_instance.sub_fruit)

When registering the workflow, this fails with the following error:

Error 0: Code: MismatchingTypes, Node Id: n4, Description: Variable [o0] (type [simple:STRING]) doesn't match expected type [simple:STRUCT  metadata:{fields:{key:"additionalProperties"  value:{bool_value:false}}  fields:{key:"properties"  value:{struct_value:{fields:{key:"name"  value:{struct_value:{fields:{key:"type"  value:{string_value:"string"}}}}}}}}  fields:{key:"required"  value:{list_value:{values:{string_value:"name"}}}}  fields:{key:"title"  value:{string_value:"Fruit"}}  fields:{key:"type"  value:{string_value:"object"}}}  structure:{dataclass_type:{key:"name"  value:{simple:STRING}}}].
Error 1: Code: ParameterNotBound, Node Id: n4, Description: Parameter not bound [fruit_instance]

Screenshots

No response

Are you sure this issue hasn't been raised already?

• Yes

Have you read the Code of Conduct?

• Yes

[welcome]

Thank you for opening your first issue here! 🛠

[runllm]

The issue you're encountering is related to Flyte's handling of complex types, particularly nested dataclasses. According to this GitHub issue, nested dataclasses are not fully supported in Flyte's type system, which can lead to type mismatches during workflow compilation.

Would you like more detail on potential workarounds or further explanation of the issue?

Sources:

• Hi! I found a bug in flytekit regarding the attribute access
• Docs: Explicitly note that nested dataclasses are not supported in the type system
• BUG: Accessing Dataclass fields fail on local execute

---

This is an AI-generated response and your feedback is appreciated! Please leave a 👍 if this is helpful and 👎 if it is not.

Mention @RunLLM to ask follow-up questions. See runllm.com for more!

[kumare3]

Cc @ByronHsu

[kumare3]

covered by #5318

[Future-Outlier]

I think this is the bug of propeller, but not related to the JSON IDL.
I'm investigating.