--config does not resolve paths relative to CWD

[cspotcode]

Prerequisites

• Checked that your issue hasn't already been filed by cross-referencing issues with the faq label
• Checked next-gen ES issues and syntax problems by using the same environment and/or transpiler configuration without Mocha to ensure it isn't just a feature that actually isn't supported in the environment in question or a bug in your code.
• 'Smoke tested' the code to be tested by running it outside the real test suite to get a better sense of whether the problem is in the code under test, your usage of Mocha, or Mocha itself
• Ensured that there is no discrepancy between the locally and globally installed versions of Mocha. You can find them with: node node_modules/.bin/mocha --version(Local) and mocha --version(Global). We recommend that you not install Mocha globally.

Description

.js config loading with --config does not handle relative paths correctly, because it calls require() with a relative path.

Here's the problem: https://github.com/mochajs/mocha/blob/master/lib/cli/config.js#L38

Steps to Reproduce

cd to an empty directory. touch foo.js

mocha --config foo.js

Expected behavior: [What you expect to happen]

mocha loads config from foo.js

Actual behavior: [What actually happens]

/c/Users/cspotcode/Documents/Personal-dev/@mochajs/mocha/lib/cli/config.js:64
    throw new Error(`failed to parse ${filepath}: ${err}`);
    ^

Error: failed to parse foobar.js: Error: Cannot find module 'foo.js'

Reproduces how often: [What percentage of the time does it reproduce?]

All the time

Versions

Mocha 6.0.2
WSL WLinux bash

Additional Information

Issue #3818

[juergba]

I don't understand why you have opened this issue.
You did realize there is already an open, active one, so please just participate in that one.

cc: @plroebuck

[plroebuck]

Uncertain whether this should be considered a bug or perhaps just in need of additional documentation. It works differently from the other parsers, but not necessarily in a bad way.

Because of implementation's use of require, his example wouldn't be interpreted as a relative path.

Interim workaround:
Always use absolute pathname with JS config files.

@boneskull
Given my druthers, continue to parse as is. Iff require.resolve fails, retry using path.resolve. It's a PITA to debug for user since the error doesn't provide enough information to debug the problem when given an unfound relative path; we should fix this aspect regardless.

[cspotcode]

It makes sense to match the behavior of other tools that support .js config files: webpack, Babel, prettier.

…

On Mon, Mar 11, 2019, 8:55 AM P. Roebuck ***@***.***> wrote: Uncertain whether this should be considered a *bug* or perhaps just in need of additional documentation. It works *differently* from the other parsers, but not necessarily in a bad way. Because of implementation's use of require, his example wouldn't be interpreted <https://nodejs.org/api/modules.html#modules_file_modules> as a relative path. Interim workaround: *Always use absolute pathname with JS config files.* @boneskull <https://github.com/boneskull> Given my druthers, continue to parse as is. Iff <https://en.wikipedia.org/wiki/If_and_only_if> require.resolve fails, retry using path.resolve. It's a PITA to debug for user since the error doesn't provide enough information to debug the problem when given an unfound relative path; we *should* fix this aspect regardless. — You are receiving this because you authored the thread. Reply to this email directly, view it on GitHub <#3822 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AAW-uC_zyKDKc0RQuhSD8tYKd2jqzjeVks5vVlJHgaJpZM4bnl5U> .

[cspotcode]

https://webpack.js.org/configuration/#use-different-config-file

webpack --config webpack.alternate.config.js

https://prettier.io/docs/en/cli.html#find-config-path-and-config

prettier --config ./my/.prettierrc --write ./my/file.js

Relevant babel issue, where the maintainer wants to require a leading ./ but log a helpful message pointing out how people can fix it.
babel/babel#8919

[plroebuck]

I already said:

Given my druthers, continue to parse as is. Iff require.resolve fails, retry using path.resolve.

You have an issue with this approach? It preserves existing behavior (used by existing issue), and provides for local file if that fails...

[cspotcode]

Correct; I disagree with that approach. It differs from the established, more intuitive behavior of other well-known tools that also load .js config files and also accept a path via --config flag.

If mocha's behavior matched webpack, babel, prettier, etc, then #3818 would never have been filed, because @AartiJ initial attempt (supplying a relative path) would have worked the first time. For mocha to intentionally deviate seems unnecessary.

[boneskull]

@juergba what issue are you referring to?

[plroebuck]

Correct; I disagree with that approach. It differs from the established, more intuitive behavior of other well-known tools that also load .js config files and also accept a path via --config flag.

If mocha's behavior matched webpack, babel, prettier, etc, then #3818 would never have been filed, because @AartiJ initial attempt (supplying a relative path) would have worked the first time. For mocha to intentionally deviate seems unnecessary.

It is exactly the same approach used to load reporters, so it's not deviating from anything.
This portion of Mocha is brand new code, and lacks some of the finesse of older portions of
the codebase.

[juergba]

@boneskull

@juergba what issue are you referring to?

Additional Information
Issue #3818