Class picker incorrectly populates Parsed Options

Describe the bug

When using the Web UI’s class picker, Parsed Options are incorrectly populated

Expected behavior

Each name of a picked class is available as a single item in the environment.parsed_options.user_classes list Example when selecting the class “PurchaseUser”:

Actual behavior

When choosing classes through class picker, the name of the class is broken into characters. Each character is present as its own item in the environment.parsed_options.user_classes list. Example when selecting the class “PurchaseUser”:

Steps to reproduce

• Start locust with the --class-picker option and without specifying a user class through the CLI
• Select a class from the class picker menu and start the test
• Access the environment.parsed_options.user_classes list in the test_start listener

@events.test_start.add_listener
def on_test_start(environment, **__):
    user_classes = environment.parsed_options.user_classes
    log.info(user_classes)

Environment

• OS: MacOS Big Sur (11.4)
• Python version: 3.7.9
• Locust version: 2.12.0
• Locust command line that you ran: locust --class-picker
• Locust file contents (anonymized if necessary):

import logging
import time
from locust import HttpUser, task, between, events

log = logging.getLogger(__name__)

@events.test_start.add_listener
def on_test_start(environment, **_):
    user_classes = environment.parsed_options.user_classes
    log.info(user_classes)

class PurchaseUser(HttpUser):
    wait_time = between(1, 5)

    @task
    def hello_world(self):
        self.client.get("/hello")
        self.client.get("/world")

    @task(3)
    def view_items(self):
        for item_id in range(10):
            self.client.get(f"/item?id={item_id}", name="/item")
            time.sleep(1)

    def on_start(self):
        self.client.post("/login", json={"username":"foo", "password":"bar"})

[mikenester]

I think this is happening when /swarm updates environment.parsed_options. I’ll try to get a fix in today or tomorrow

[cyberw]

@Vino4 's comment makes sense to me.