fix: return 404 for ENOTDIR

[kalinkrustev]

Inert will return error 500 for non-existing files, when part of the path resembles an existing file.
For example if /a/b/c.html is existing file, requesting /a/b/c.html/d will return 500 instead of 404.

ENOTDIR is listed here https://nodejs.org/api/errors.html#common-system-errors

[kanongil]

Thanks for your contribution. This seems like a valid issue, and a 404 is probably the appropriate response.

However, we can't merge this PR without a new test case, which tests this.

[kalinkrustev]

OK, I will try to prepare some tests

[kalinkrustev]

tests should be ok now

[kanongil]

Hmm, I'm afraid that this error is not used on windows, which causes the coverage check to fail. This is complicated to fix, since the test will need to inject a fake error on windows (inside an if (process.platform === 'win32') { … }) like here:

inert/test/file.js

Lines 1073 to 1078 in ae77ea5

	const orig = InertFs.fstat;
	InertFs.fstat = function (fd) { // can return EIO error
	InertFs.fstat = orig;
	throw new Error('failed');
	};

[kalinkrustev]

check again, should be ok now

[kanongil]

Clever fix. We are almost there, just a few more details to finish.

[devinivy]

Thanks to both of you for working through this— it's a good fix and looks very close to 100% complete as Gil mentioned above. 💎 👍

[kanongil]

Ping for merge and publish?