Full page screenshot fails when defaultViewport is null

[k3mayo]

Steps to reproduce

Tell us about your environment:

• Puppeteer version: 1.7.0
• Platform / OS version: Windows 7
• URLs (if applicable):
• Node.js version: v9.10.1

What steps will reproduce the problem?

const puppeteer = require('puppeteer');

(async () => {
    const browser = await puppeteer.launch({ headless: false, defaultViewport: null });
    const page = await browser.newPage();
    await page.goto('https://www.google.com/');
    await page.screenshot({ path: 'example.png', fullPage: true });
    await browser.close();
})();

What is the expected result?
No error and screenshot is saved.

What happens instead?
UnhandledPromiseRejectionWarning: TypeError: Cannot read property 'isMobile' of null

[yanivefraim]

Trying this gave me a different error:

fullPage screenshots do not work without first setting viewport. (source)

Is this still considered a bug?

[aslushnikov]

@yanivefraim yeah; viewport should not be necessary to do a full-page screenshot.