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fix: handle cancelled tasks#536

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cruzdanilo wants to merge 1 commit intomicrosoft:masterfrom
cruzdanilo:cancelled-tasks
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fix: handle cancelled tasks#536
cruzdanilo wants to merge 1 commit intomicrosoft:masterfrom
cruzdanilo:cancelled-tasks

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@cruzdanilo
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@cruzdanilo cruzdanilo commented Mar 1, 2021

prevents InvalidStateError when the task has been cancelled, here:

callback.future.set_exception(parsed_error)

@pavelfeldman
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pavelfeldman commented Mar 3, 2021

Do you have a reproduction for this bug? callback.future.set_exception and callback.future.set_result are in different branches of if, they can't both happen.

@cruzdanilo
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cruzdanilo commented Mar 3, 2021 

from asyncio import FIRST_COMPLETED, CancelledError, create_task, run, wait
from contextlib import suppress
from playwright.async_api import async_playwright

async def main():
    async with async_playwright() as p:
        browser = await p.chromium.launch()
        page = await browser.new_page()
        await page.goto("http://playwright.dev")
        done, pending = await wait({
            create_task(page.wait_for_selector("input[placeholder='search' i]")),
            create_task(page.wait_for_selector("input[placeholder='will-never-find' i]")),
        }, return_when=FIRST_COMPLETED)
        for task in pending:
            task.cancel()
            with suppress(CancelledError):
                await task

        await browser.close()

run(main())
Task exception was never retrieved
future: <Task finished name='Task-2' coro=<Connection.run() done, defined at lib/python3.9/site-packages/playwright/_impl/_connection.py:163> exception=InvalidStateError('invalid state')>
Traceback (most recent call last):
  File "lib/python3.9/site-packages/playwright/_impl/_connection.py", line 166, in run
    await self._transport.run()
  File "lib/python3.9/site-packages/playwright/_impl/_transport.py", line 90, in run
    self.on_message(obj)
  File "lib/python3.9/site-packages/playwright/_impl/_connection.py", line 150, in <lambda>
    self._transport.on_message = lambda msg: self._dispatch(msg)
  File "lib/python3.9/site-packages/playwright/_impl/_connection.py", line 229, in _dispatch
    callback.future.set_exception(parsed_error)
asyncio.exceptions.InvalidStateError: invalid state

@pavelfeldman
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pavelfeldman commented Mar 22, 2021

Got it, I did not realize the task was canceled externally. Would you mind adding this as a test for it?

@mxschmitt mxschmitt mentioned this pull request Apr 16, 2021
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mxschmitt commented Apr 16, 2021

I picked it up in #624 so it lands earlier. Thanks for the repo and explanation!

@mxschmitt mxschmitt closed this Apr 16, 2021
@Unintendedz Unintendedz mentioned this pull request Mar 18, 2022
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3 participants

@cruzdanilo @pavelfeldman @mxschmitt