Support custom feature configuration

[gnunicorn]

Quoting @mcarton on #1:

Also tested it, it reports warning in a file guarded by

#![cfg_attr(feature="clippy", allow(float_cmp))]

Clippy is often used with a clippy, dev, nightly, testing or whatever feature in the wild, does the service have a way to compile with a given feature?

[gnunicorn]

And to quote myself:

@Manishearth , @mcarton could you elaborate why the conf_attr things doesn't work in the rustc approach I am currently taking? And maybe what we can do about that? Is this because the we don't pass that config? I was thinking of allowing some customization of the rustc command via a .clippy.tomlin the same folder. There the owner could configure they want "feature" xyz, would that solve the issue?

[mcarton]

Note that Clippy might get a Clippy.toml file by itself (see https://github.com/Manishearth/rust-clippy/pull/698). Adding another .clippy.toml file would be confusing at best. If this is the way we choose, we could just add the conf there.

[gnunicorn]

@mcarton: good point. Will that config contain a way to configure said features from there?

[mcarton]

No, Clippy cannot change the features itself.

[mrmonday]

Another option might be to include it in the URL, along with the repo and branch.

[Manishearth]

At the same time, we could allow a [service] clippy-feature="nightly" key in the toml. Clippy itself can ignore it, but clippy-service reads it. No reason we can't share a conf file :smile:

[mcarton]

No reason we can't share a conf file

Of course, but with the current PR any unknown key is an error. Should I just white-list [service] (but then what about other tools?) or ignore all unknown keys (which means eg. spelling mistake in the conf file will be hard to notice).

[Manishearth]

Nah, just whitelist [service]. Or we'll call it [third-party] or [external]

[mcarton]

Ok then, I’ve white-listed third-party, I preferred that name.

[gnunicorn]

Well, I wait for https://github.com/Manishearth/rust-clippy/pull/698 to be merged then. After that I will tackle this as part of the config-file milestone!

[indiv0]

https://github.com/Manishearth/rust-clippy/pull/698 has been merged. Any update on this?

[gnunicorn]

@indiv0 no work on this yet (from my side), but I am accepting Pull-Requests :-) !