[BUG] Page.screenshot method hangs indefinitely

[mat926]

System info

• Playwright Version: v1.40.0
• Operating System: All
• Browser: Chromium
• Other info: 32GB RAM

Source code

from playwright.sync_api import sync_playwright

print("Starting...")

with sync_playwright() as p:
    try:
        browser = p.chromium.launch(headless=False)
        page = browser.new_page()
        for index in range(10000):
            print("Iteration:", index)
            page.goto('https://google.com')


    except Exception as error:
        if page:
            print("Error: ", {error})
            page.screenshot(path='error.png', timeout=0)
            print("Took a screenshot")

• I provided exact source code that allows reproducing the issue locally.

Link to the GitHub repository with the repro

Test file (self-contained)

Steps

• Run the code
• Wait until the for loop crashes at about 2000-3000 iterations

Expected

The for loop runs all the way through and not crash.
The page.screenshot runs normally.

Actual
At the 2652 iteration, a Timeout exception gets caught. Chrome gets an Out of Memory error.
The code hangs at the page.screenshot line and never completes.

Screenshot

[mxschmitt]

I can repro, hangs for me with:

await page.goto("chrome://crash").catch(e => console.log(e));
await page.screenshot({ path: `crash.png` })

at:

   pw:api waiting for fonts to load... +250ms

[Rafiot]

I have the same issue, when I pass PLAYWRIGHT_CHROMIUM_USE_HEADLESS_NEW=1 (which is very similar to headless=False, if I'm not mistaken).

And this issue has probably the same root cause: #29968

If you have an idea how to somehow force a timeout on loading the fonts?

[LucaLis]

Hi. I'm facing similar issue - sometimes my tests are getting stuck when i'm tryigng to take screenshot. I'm using Playwright 1.42.0. I've investigated logs using DEBUG=pw:* and i can see that right after calling page.screenshot playwright logs

pw:api waiting for fonts to load...

which is followed by a bunch of
pw:protocol SEND {"id": XYZ (...) "document.fonts.ready" (...)

usually these SEND requests recieve immediate response like:

pw:protocol RECV {"id" XYZ (...)

but sometimes it takes several minutes - this is clearly causing problems and leads to hanging screenshot method.

Ofc screenshot method throws a timeout but subsequent screenshot calls from the same browser context seem to be affected and it's basically not possible to capture screenshot anymore.

It seems to be somewhat related with #29968

I hope that this will help to find the root cause and fix the problem...

[marian51]

I have a similar issue. In "headless" mode there is no problem, but in "headed" mode every test stucks at taking a screenshot (interestingly, a week ago it was working more or less fine - the tests only stucked on one screenshot and all you had to do was give locator.focus() there, but it is not working).

Now, in my case, a workaround works - I gave this before each test

test.beforeEach(async ({ page }) => {
    await page.route('**/*.css', (route) => { route.abort(); });
});

and it looks like everything is working fine.

[jonisrael]

I am also experiencing this "waiting for fonts to load" bug in headed mode that leads to a hanging page.screenshot command, but can confirm that in headless mode everything works fine. However in some cases I need to be in headed mode -- is there any way to fix this bug?

[BaseerAzhar]

except Exception as error:

      raise rewrite_error(error, f"{parsed_st['apiName']}: {error}") from None

E Call log:
E taking page screenshot
E - waiting for fonts to load...
E - fonts loaded

Still getting this issue.. the same methods works in some pages of headed, but stucks at some of the new test cases.

[azrafe7]

Was getting this too (and only on some pages, while on others worked)...
Setting the env variable PW_TEST_SCREENSHOT_NO_FONTS_READY to 1 seems to have fixed the problem for me.

Found out about it by inspecting the screenshotter code at:

playwright/packages/playwright-core/src/server/screenshotter.ts

Line 267 in c3d8b22

if (!process.env.PW_TEST_SCREENSHOT_NO_FONTS_READY) {

[Rafiot]

It would be really amazing to have a list of these env variables as they're pretty amazing but you only find them if you dig through the source code.

I can also confirm is solves my problems.

[charlesloubao]

Worked for me as well thank you @azrafe7

[mxschmitt]

@Rafiot @charlesloubao would it be possible to share a repro with us?

[Rafiot]

I get that fairly consistently on liberation.fr and trigger a full page screenshot (not just the viewport).

[mxschmitt]

@Rafiot could you help us a with a repro? I tried the following and it works for me:

import { chromium } from 'playwright';

(async () => {
  const browser = await chromium.launch({ headless: true });
  const context = await browser.newContext();
  const page = await context.newPage();
  await page.goto('https://liberation.fr');
  await page.waitForTimeout(10_000);
  await page.screenshot({ fullPage: true, path: 'screenshot.png' });

  await context.close();
  await browser.close();
})();

[Rafiot]

I'll not have time to work on that today, sorry. Hopefully early next week. If that's important, I'm using the new headless (which is very similar to headfull, afaict).

[Rafiot]

I don't seem to be able to reproduce it anymore.

[Rafiot]

Glad someone else managed to give you a proper test, and I confirm I can reproduce too (even without slomo setting).

I'm super curious to know what's causing that.

[derdeka]

@pavelfeldman as you have implemented this "wait for fonts" stuff in #28226, can you briefly explain how it's supposed to work?

[mxschmitt]

We landed a fix in Canary, feel free to try or wait for 1.45. I'll close it for now, for further bug reports in Canary / 1.45 (to be released) please file new bug reports - thank you for your understanding!

[coader]

I use 1.48 but still got this error

[You-Honey]

I use "@crawlee/playwright": "3.9.1" and have the problem. @azrafe7's fix works though.

Ping @mxschmitt