[Roadmap] Configuration file for lints

[flip1995]

This is something that comes up every now and then: a reusable configuration
file, where lint levels can be defined. Discussions about this often lead to
nothing specific or to "we need an RFC for this". And this is exactly what needs
to be done. Get together with the cargo team and write an RFC and implement such
a configuration file somehow and somewhere.

• Cargo tracking issue: Support defining enabled and disabled lints in a configuration file cargo#5034
• IRLO post

Steps to completion:

• Draft a RFC
• Coordinate with the cargo team and publish the RFC
• Bikeshedding
• Implement the configuration (file) in cargo

[matthiaskrgr]

I wondered if it is somehow possible to declare a (proc?) macro in an extern crate that expands to a bunch of allow/deny directives and can be imported into crates where you want the warnings.
Unfortunately rustc does not seem to like the idea :( https://play.rust-lang.org/?version=nightly&mode=debug&edition=2018&gist=7b020af857b7622d0cc9e3422f52c020

[CPerezz]

I've been a couple of days taking a look to this and I was also thinking about post something in the IRLO and arrive to an RFC which we could start to work towards.

Do you need some help on Drafting the RFC and implementing the stuff? I would be happy to help 😃

[flip1995]

Help on drafting the RFC would be nice. I don't think another forum post will help much. Every discussion on this topic let to the same conclusion: this needs an RFC.

[CPerezz]

Should we setup a hackmd or something similar? Or What do you have in mind?

[flip1995]

Yeah, I think a hackmd would be nice. I started one here and filled out summary and motivation. You have to sign in to hackmd.io in order to edit it. You can use your GH account for that. (I just want some low barrier of entrance to protect us from spammers).

---

One thing that is important is, that it is clear, that the draft should not set the syntax of the configuration in stone. Also it is an open question if it should be an extra file or included in Cargo.toml (or a hybrid). Both of this should be discussed in the RFC.

[CPerezz]

Absolutely! Will start later on today then! 😃 Thanks @flip1995 !

[CPerezz]

Added:

• Prior-art section -> https://hackmd.io/tSa8HUOYS2Cxo4PkItmcYw?view#Prior-art Needs a bit more work and highlight some ideas that were interesting and given in the comments but it's mostly there.
• Unresolved questions -> https://hackmd.io/tSa8HUOYS2Cxo4PkItmcYw?view#Unresolved-questions Noted the things that came to my head and wanted to discuss.

Will complete the sections by the end of the weekend. Feel free to ask or comment anything! 😃

[flip1995]

Thanks! I may put some time into this the next few days as well.