ignoreDefaultArgs launch parameter is broken

[Granitosaurus]

I'm trying to disable default launch arguments however when this parameter is set to True one of two things happen:

browser: Browser = chromium.launch(ignoreDefaultArgs=True)

will break with:

  File "/home/user/.local/lib/python3.8/site-packages/playwright/browser_type.py", line 66, in launch
    normalize_launch_params(params)
  File "/home/user/.local/lib/python3.8/site-packages/playwright/browser_type.py", line 140, in normalize_launch_params
    params["env"] = {name: str(value) for [name, value] in params["env"].items()}
KeyError: 'env'

I've made a hotfix patch here Granitosaurus@2dc0e10 now the browser launches fine but timesout on launch() call:

Traceback (most recent call last):
  File "/home/user/.local/lib/python3.8/site-packages/playwright/browser_type.py", line 68, in launch
    return from_channel(await self._channel.send("launch", params))
  File "/home/user/.local/lib/python3.8/site-packages/playwright/connection.py", line 39, in send
    result = await callback.future
  File "/usr/lib/python3.8/asyncio/futures.py", line 260, in __await__
    yield self  # This tells Task to wait for completion.
  File "/usr/lib/python3.8/asyncio/tasks.py", line 349, in __wakeup
    future.result()
  File "/usr/lib/python3.8/asyncio/futures.py", line 178, in result
    raise self._exception
playwright.helper.TimeoutError: Timeout 30000ms exceeded.
=========================== logs ===========================
<launching> /home/user/.cache/ms-playwright/chromium-799411/chrome-linux/chrome 
<launched> pid=301672
[err] [301699:301699:0914/061714.839670:ERROR:sandbox_linux.cc(374)] InitializeSandbox() called with multiple threads in process gpu-process.

[Granitosaurus]

I thought it might be hanging because some of browser flags were required but I popped the defaults from playwright repo here https://github.com/microsoft/playwright/blob/ed3b00efdf0d2e44fc667ade8298ac6d504109bf/src/server/chromium/chromium.ts#L151 and passed them to launch(args=) and unfortunately it's still timing out on launch:

browser_args = [
  '--disable-background-networking',
  '--enable-features=NetworkService,NetworkServiceInProcess',
  '--disable-background-timer-throttling',
  '--disable-backgrounding-occluded-windows',
  '--disable-breakpad',
  '--disable-client-side-phishing-detection',
  '--disable-component-extensions-with-background-pages',
  '--disable-default-apps',
  '--disable-dev-shm-usage',
  '--disable-extensions',
  # BlinkGenPropertyTrees disabled due to crbug.com/937609
  '--disable-features=TranslateUI,BlinkGenPropertyTrees,ImprovedCookieControls,SameSiteByDefaultCookies,LazyFrameLoading',
  '--disable-hang-monitor',
  '--disable-ipc-flooding-protection',
  '--disable-popup-blocking',
  '--disable-prompt-on-repost',
  '--disable-renderer-backgrounding',
  '--disable-sync',
  '--force-color-profile=srgb',
  '--metrics-recording-only',
  '--no-first-run',
  '--enable-automation',
  '--password-store=basic',
  '--use-mock-keychain',
]
pw.chromium.launch(args=browser_args, ignoreDefaultArgs=True)
# or 
pw.chromium.launch(args=['--enable-automation'], ignoreDefaultArgs=True)
# alternatively passing this list to ignoreDefaultArgs doesn't seem to disable the flags.
pw.chromium.launch(ignoreDefaultArgs=browser_args)

From what I understand here:

pw.chromium.launch(args=browser_args, ignoreDefaultArgs=True)
# should be equivalent of 
pw.chromium.launch()

[mxschmitt]

Hi, thanks for reporting and digging into that issue. I created a patch to fix this behaviour.

[Granitosaurus]

I've tried the patched branch and it fixes the first error but it still hangs indefinitely if started with ignoreDefaultArgs=True

[mxschmitt]

I've tried the patched branch and it fixes the first error but it still hangs indefinitely if started with ignoreDefaultArgs=True

Yeah since it probably removes some arguments which we need internally. What are you trying to archive? Does maybe ignoring a selection of arguments help you?

[Granitosaurus]

Maybe my default argument list is incorrect but assuming it is correct shouldn't:

pw.chromium.launch(args=browser_args, ignoreDefaultArgs=True)
# be equivalent of 
pw.chromium.launch()

I'm trying to debug some unusual behavior I see in playwright's browser but not in desktop browser. Presumably it's being caused by one of these flags. For example launch(ignoreDefaultArgs=['--incognito']) still starts the browser in incognito mode, with launch(ignoreDefaultArgs=True) the browser starts in normal mode but hangs. Seems like ignore list of arguments doesn't work?

[mxschmitt]

Maybe my default argument list is incorrect but assuming it is correct shouldn't:

pw.chromium.launch(args=browser_args, ignoreDefaultArgs=True)
# be equivalent of 
pw.chromium.launch()

I'm trying to debug some unusual behavior I see in playwright's browser but not in desktop browser. Presumably it's being caused by one of these flags. For example launch(ignoreDefaultArgs=['--incognito']) still starts the browser in incognito mode, with launch(ignoreDefaultArgs=True) the browser starts in normal mode but hangs. Seems like ignore list of arguments doesn't work?

We unfortunately require the usage of an incognito tab internally: microsoft/playwright#2071

[Granitosaurus]

The patch doesn't fix the issue though.
I could not get any of the ignoreDefaultArgs functions working, none of the flags passed to ignoreDefaultArgs are ignored and setting it to True even by supplying all of the upstream default flags manually hangs the process. Did I miss something? 😬

Additionally I think it would be great to document default browser launch flags (DefaultArgs) somewhere because now it's extremely difficult to debug why playwright browser is seeing different page compared to the user i.e. it's hard to use as a testing framework if it cannot properly simulate user.

[mxschmitt]

I tried it and for me it's working. (Tested ignoreDefaultArgs: ['--mute-audio']
and checked the launch internally by setting the DEBUG=pw* env var.)

Maybe launchPersistentContext fits for your needs?

Why different? Would be great to know why the behavior is different. And which behavior.

Thanks!

[humanperzeus]

im running into the issue that i can't set the browser size via args what's wrong with the command?

browser_args = ['viewport: {width: 1280, height: 720}']
browser = await playwright.webkit.launch(headless=False, args=browser_args)

[mxschmitt]

You can set the viewport when creating a context: https://playwright.dev/#version=v1.5.2&path=docs%2Fapi.md&q=browsernewcontextoptions--options-viewport-width

So

browser.newContext(viewport={
    "width": 1280,
    "height": 720,
})

should work. Is this what you want?

[maxktz]

why in this code:
https://github.com/microsoft/playwright/blob/5faf6f9e69c2148e94c81675fb636eb31a02b5e7/src%2Fserver%2Fchromium%2Fchromium.ts#L87

they don't check for ignoreDefaultArgs at all