existsSync throws an error instead of returning false in Node 11

[nzakas]

Environment Info:

$ node --version
v11.2.0
$ npm --version
6.4.1
$ nvm --version
0.33.11

MockFS version: 4.7.0

We recently found one test using mock-fs that fails consistently in Node.js v11:
https://travis-ci.org/eslint/eslint/jobs/456094527#L484

This occurs because existsSync ends up throwing an error instead of returning false (which it does consistently in other Node.js versions).

The test in question looks like this:

describe("checkPackageJson()", () => {
    after(() => {
        mockFs.restore();
    });

    it("should return true if package.json exists", () => {
        mockFs({
            "package.json": "{ \"file\": \"contents\" }"
        });

        assert.strictEqual(npmUtils.checkPackageJson(), true);
    });

    it("should return false if package.json does not exist", () => {
        mockFs({});
        assert.strictEqual(npmUtils.checkPackageJson(), false);
    });
});

The first test passes while the second one throws an error in Node.js 11 (Node.js 6, 8, and 10 all pass). npmUtils.checkPackageJson() calls fs.existsSync under the covers.

[maxwellgerber]

#254 (comment)
I'm not the maintainer for this library so take this with a grain of salt - I don't think mock-fs as it is currently implemented will ever support Node 11+.

[nzakas]

Ah, thanks for the heads up.

…

On Sat, Nov 17, 2018 at 2:52 AM Maxwell Gerber ***@***.***> wrote: #254 (comment) <#254 (comment)> I'm not the maintainer for this library so take this with a grain of salt - I don't think mock-fs as it is currently implemented will ever support Node 11+. — You are receiving this because you authored the thread. Reply to this email directly, view it on GitHub <#256 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AACWkprdfYK0JoPXdPC-Nn0f8YlhI7fRks5uv-pbgaJpZM4YnAr3> .

--

______________________________ Nicholas C. Zakas @SlickNet Author, Principles of Object-Oriented JavaScript <http://amzn.to/29Pmfrm> Author, Understanding ECMAScript 6 <http://amzn.to/29K1mIy>

[mheggeseth]

This has found its way into (v10.14.2 LTS) independent of making process.binding() internal. existsSync was updated to use the synchronous version of process.binding("fs").access().

[jan-molak]

Same issue with node 10.14.2 - mock-fs fs.existsSync throws ENOENT instead of returning false

[pirog]

For those interested, currently using this as a workaround:
491fec8

No idea whether that is a good fix or not so YMMV

[tschaub]

Thanks for the report @nzakas. The 4.8.0 release addresses issues with Node 11 (and 10) compatibility (thanks @huochunpeng, see #260).

[nzakas]

Awesome, thank you!