[Bug]: '_projectRoot is undefined. Unable to create a BrowserFetcher.' ( v18.0.4 )

[cenfun]

Bug description

Steps to reproduce the problem:

const puppeteer = require('puppeteer-core');
const browserFetcher = puppeteer.createBrowserFetcher({
        path: 'to-my-path'
    });

throw a error:
node_modules\puppeteer-core\lib\cjs\puppeteer\node\Puppeteer.js:206
throw new Error('_projectRoot is undefined. Unable to create a BrowserFetcher.');
^
Error: _projectRoot is undefined. Unable to create a BrowserFetcher.

API createBrowserFetcher broken, it's works on previous version

Puppeteer version

v18.0.4

Node.js version

v16.17.0

npm version

8.18.0

What operating system are you seeing the problem on?

Windows

Relevant log output

No response

[jrandolf]

See #8919

[jtymes]

I am running into this issue. I am using puppeteer-core only to use its BrowserFetcher to download a known-good revision. As it stands right now, the change introduced in #8907 completely breaks the createBrowserFetcher functionality with puppeteer-core, because _projectRoot will always be undefined. I don't think #8919 offers a solution for that.

One way to fix this could be if path is being passed in the FetcherOptions, it should skip the check on _projectRoot.

[jrandolf]

Could you try puppeteer instead of puppeteer-core?

[EDIT]: Scratch that. I assume you are looking to just have the launcher as a separate API. There are some discussions regarding this. If all goes well, it should be come a separate API this quarter. We will see.

[jtymes]

We likely can switch to puppeteer, with a bit of additional configuration. It still leaves puppeteer-core with a broken createBrowserFetcher function that comes back as part of the PuppeteerNode class. If that's the intent, I think it should at least be documented.

[cenfun]

thanks @jrandolf
Here's some background
Why puppeteer-core, because we don't want to download chromium when running "npm install", and the chromium size is very large (400M unzipped)
Why createBrowserFetcher, because we want to download chromium to a different directory like user directory but not node_modules, so it can be cached
So puppeteer-core + createBrowserFetcher can solve these usage scenarios very well, but it is broken now
However we can directly call BrowserFetcher to solve it

//fix '_projectRoot is undefined. Unable to create a BrowserFetcher.'
const { BrowserFetcher } = require('puppeteer-core/lib/cjs/puppeteer/node/BrowserFetcher.js');
const createBrowserFetcher = (options) => {
    return new BrowserFetcher('', options);
};
// instead of puppeteer.createBrowserFetcher()

It's just that BrowserFetcher is not a public API, we still hope to fix the public API createBrowserFetcher, thanks again.

[bm2ilabs]

Just remove node_modules/puppeteer-core/ if you are using puppeteer-extra