make use of util.inspect.custom

[hiroppy]

What kind of change does this PR introduce?

Currently, WebpackError.unittest.js test has failed.

Did you add tests for your changes?

no

Does this PR introduce a breaking change?

no

What needs to be documented once your changes are merged?

[webpack-bot]

For maintainers only:

• This need to be documented (issue in webpack/webpack.js.org will be filed when merged)

[hiroppy]

This test gets "{ CustomError: CustomMessage" when using Node v11.4.0.
But when Node is v10.15.1, it will get "CustomError: CustomMessage".

@sokra Could you tell me the version of Node in this log? #8738 (comment)

[sokra]

node 10.

starting with node 11 util.inspect will no longer use the inspect property of the object.

In lib/WebpackError util.inspect.custom need to be used instead to make it consistent for node >10 too

See here: https://nodejs.org/docs/latest/api/util.html#util_util_inspect_custom

[hiroppy]

@sokra Thank you for the information! Updated the code. PTAL 🙇

[sokra]

Seem like the CI didn't catch that, because unittest only run on node.js 10, but the node.js documentation states that Symbol.for('nodejs.util.inspect.custom') was added with node 10.12.0, while util.inspect.custom was added in node 6.

https://nodejs.org/docs/latest/api/util.html#util_util_inspect_custom in History

v10.12.0 | This is now defined as a shared symbol.

[sokra]

Suggested change

	const inspect = Symbol.for("nodejs.util.inspect.custom");
	const inspect = require("util").inspect.custom;

[webpack-bot]

@hiroppy Thanks for your update.

I labeled the Pull Request so reviewers will review it again.

@sokra Please review the new changes.

[hiroppy]

Ah, I see. Updated:)

[webpack-bot]

Thank you for your pull request! The most important CI builds succeeded, we’ll review the pull request soon.

[sokra]

Thanks