TypeError raised if type variable is defined before a locust class

[daara-s]

Prerequisites

• I am using the latest version of Locust
• I am reporting a bug, not asking a question

Description

I found a bug which raises the stack-trace below when defining a type variable before a locust class.
It looks to only affect when setting a type as shown in the MWE, though I've not tested many variations.

Removing RequestDict = dict[str, object] fixed the issue.

✦ ❯ locust -f scripts/locustfile.py
Traceback (most recent call last):
  File "/Users/daarashaw/dev/repo/.venv/bin/locust", line 8, in <module>
    sys.exit(main())
  File "/Users/daarashaw/dev/repo/.venv/lib/python3.10/site-packages/locust/main.py", line 112, in main
    docstring, _user_classes, shape_classes = load_locustfile(_locustfile)
  File "/Users/daarashaw/dev/repo/.venv/lib/python3.10/site-packages/locust/util/load_locustfile.py", line 83, in load_locustfile
    shape_classes = [value() for value in vars(imported).values() if is_shape_class(value)]
  File "/Users/daarashaw/dev/repo/.venv/lib/python3.10/site-packages/locust/util/load_locustfile.py", line 83, in <listcomp>
    shape_classes = [value() for value in vars(imported).values() if is_shape_class(value)]
  File "/Users/daarashaw/dev/repo/.venv/lib/python3.10/site-packages/locust/util/load_locustfile.py", line 24, in is_shape_class
    return bool(inspect.isclass(item) and issubclass(item, LoadTestShape) and not getattr(item, "abstract", True))
  File "/Users/daarashaw/.pyenv/versions/3.10.13/lib/python3.10/abc.py", line 123, in __subclasscheck__
    return _abc_subclasscheck(cls, subclass)
TypeError: issubclass() arg 1 must be a class

Command line

locust -f scripts/locustfile.py

Locustfile contents

import json
import random
from pathlib import Path

from locust import HttpUser, between, task
from typing_extensions import override

RequestDict = dict[str, object]


class RequestGenerator(HttpUser):
    host = "http://some_endpoint"

    wait_time = between(1, 3)  # type: ignore[no-untyped-call]

    @override
    def on_start(self) -> None:
        self.requests: list[RequestDict] = self.load_requests()

    def load_requests(self) -> list[RequestDict]:
        json_files = (Path(__file__).parents[1] / "tests" / "jsons").glob("*.json")
        return [json.loads(file.read_text()) for file in json_files]

    @task
    def calculate(self) -> None:
        request = random.choice(self.requests)

        self.client.post(
            "/calculate",
            json=request,
        )

Python version

3.10.13

Locust version

2.32.4

Operating system

MacOS 14.6.1 (23G93)