Proposal: Deprecate `process.features.ipv6` and `process.features.uv`

[Renegade334]

process.features.ipv6 and process.features.uv have both been hard-coded to true since pre-v1.0.0. Indeed, by the looks of things, process.features.ipv6 has always been hard-coded to true since process.features was first added.

There has been a longstanding todo comment about improving the features API (cc @joyeecheung) but for now, seems like deprecating these would be fairly uncontroversial.

[marco-ippolito]

pr welcome

[Renegade334]

Where would you recommend these live in terms of deprecation cycle? They've been redundant for well over a decade, so is there a case for sending them straight to runtime?

The tls_* properties are also redundant since v11.0.0 (a76f029) so could probably also take the opportunity to doc-deprecate these.

[avivkeller]

so is there a case for sending them straight to runtime?

I don't believe so, IIRC everything must go through the cycle.

[bnoordhuis]

Doc-deprecating is fine (if kind of pointless IMO) but runtime warnings or removing them is potentially disruptive for no benefit whatsoever.

Having a few superfluous properties doesn't cost anything. Just keep them around forever.