lib: end-of-life the deprecated require('sys')

[sam-github]

See: #2405

It looks like this was going to be considered for Node.js 6.x, so now that 12.x is upcoming, maybe we are ready?

Checklist

• make -j4 test (UNIX), or vcbuild test (Windows) passes
• tests and/or benchmarks are included
• documentation is changed or added
• commit message follows commit guidelines

[nodejs-github-bot]

@sam-github sadly an error occured when I tried to trigger a build :(

[vsemozhetbyt]

Maybe:

Suggested change

	The `sys` module is deprecated. Please use the [`util`][] module instead.
	The `sys` module was removed. Please use the [`util`][] module instead.

[vsemozhetbyt]

(Not sure where the leading space emerges from)

[targos]

Suggested change

	'no-restricted-modules': ['error'],
	'no-restricted-modules': 'error',

[Trott]

This line should be deleted entirely. If you don't specify a second argument, the rule does nothing.

[targos]

Suggested change

	pr-url: XXX
	pr-url: https://github.com/nodejs/node/pull/26292

[Fishrock123]

i know there are still modules that use this 😐

[Trott]

The maintenance burden of the sys module is roughly zero. The cost to the ecosystem of removing sys is not zero. I don't think we should remove unless there is a compelling benefit to doing so. It's fine to leave it permanently deprecated.

[Trott]

I'm surprised test/parallel/test-sys.js does not show up as being removed in the diff. That test should fail with this change.

[Fishrock123]

To be clear: I think there is a cost of keeping sys around. There is a cost of confusion to our users. I do not think this is good to keep going in perpetuity, as it will only become worse.

[Trott]

To be clear: I think there is a cost of keeping sys around. There is a cost of confusion to our users. I do not think this is good to keep going in perpetuity, as it will only become worse.

@Fishrock123 I'm surprised at the notion that the cost of confusion to users is significant in this instance. I have literally never heard of anyone being confused about sys vs. util since 4.0.0, probably even earlier than that. It doesn't seem to ever come up in the help repo, in this repo, in StackOverflow, or in IRC. Am I wrong?

[Trott]

Might not be a bad idea for someone to do something like https://github.com/evanlucas/find-sys all over again (maybe using gzemnid?).

[bnoordhuis]

We decided years ago to never give up the 'sys' namespace for security reasons but this PR appears to be doing just that. require('sys') (or any other built-in module) should never load third-party code.

[jasnell]

I agree with @bnoordhuis ... we cannot remove the module name completely.

We could however, upgrade from a deprecation warning to an actual thrown Error.

[BridgeAR]

Throwing an error as suggested by @jasnell seems best to me instead of freeing the namespace.

[cjihrig]

I agree that we should not give up the name sys. Assuming that we don't give up the name, throwing an error doesn't seem productive... we might as well continue with the existing behavior.

[sam-github]

I didn't think this would be so controversial! My reading of #2405 was that it was likely to be deleted for 6.x, so 12.x seemed like a pretty safe overshoot.

Anybody using sys has been getting console warnings that its deprecated for 3.5+ years. Personally, I think that's a fair amount of time to update, but I don't feel really strongly about it. I can add a test that the deprecation is emitted and call it a day if that's what the consensus is.

The presence of sys has some cost, at the very least, that _linkedlist got deleted and _stream_wrap.js is about to get deprecated along with #2405's discussion made me think this was the time to cleanup sys, so it cost me some time. I guess a comment in the source saying "we'll never delete this, please don't try, see #26292" would be good if that's the decision

If there is agreement to delete it, I'll fix up the PR, but I'm not going to lose more time on it if there isn't. I'll wait for more comment, or maybe it needs a TSC agenda label?

• @cjihrig@bnoordhuis It wasn't my intention to give up sys, that was an oversight, if we want to remove sys I'll fix that.

• @vsemozhetbyt The text and metadata of the deprecation docs is identical to that used in the _linklist module end-of-life. If this text needs changing, I'll update the other one, too.

• We gave up _linklist to npm, oversight, or not considered a security issue?

core/node (remove-deprecated-sys $%) % cat node_modules/_linklist/index.js
console.log('_linklist')
core/node (remove-deprecated-sys $%) % node -p 'require("_linklist")'
_linklist
{}

[vsemozhetbyt]

The text and metadata of the deprecation docs is identical to that used in the _linklist module end-of-life. If this text needs changing, I'll update the other one, too.

No strong opinion. Please, do as you would consider being better.

[bnoordhuis]

We gave up _linklist to npm, oversight, or not considered a security issue?

Oversight, I'm afraid. We should probably claim it while we still can. :-)

[targos]

We gave up _linklist to npm, oversight, or not considered a security issue?

Oversight, I'm afraid. We should probably claim it while we still can. :-)

We can't. npm doesn't allow package names that start with an underscore.

[sam-github]

I think I'll just leave this alone.