Rust-clippy: Idea: FIXME lints

[Centril]

I am unsure of whether this is the right place for this issue.

The idea was originally brought up at: https://github.com/rust-lang/rfcs/issues/2281#issuecomment-355986157

I haven't seen it personally yet (I'm still in college after all), but I've heard plenty of stories about how kludges and temporary workarounds end up being permanent simply because no one got around with putting a more robust fix in place. We can't fix developer laziness, but perhaps something like this could help people not forget tasks they defer to later, in general.

warning: FIXME not resolved for 2 years

One could perhaps write:

#[cfg_attr(feature = "cargo-clippy", FIXME("2018-01-15", "<description of what to fix>"))]

[eaglgenes101]

When I wrote of my original suggestion, I was thinking of it being rolled together with the RFC I suggested it on, based on time rather than availability or stability of features. But since it's been split off, I'll go along with it.

That said, giving it a fresh look, the most obvious problem would be to get people on board the new format, or to make the tools smart enough to figure things out for the end user. This might need some more thought than I first imagined.

[shaleh]

If clippy learned Git, you could find when the FIXME was added and compare that to current time. Which means the developer does not need to use a new format.

Or perhaps this is better done in a different linter.

[clarfonthey]

Perhaps adding a fixme attribute to the compiler itself is a good idea?

[Centril]

@shaleh That seems like an effective idea, but I'd prefer not to have to jump between tools, it is better to just have to execute one command for all lints in my opinion. Also, not all projects use git =)

[shaleh]

I used Git as an example. A similar solution would work with other revision systems.

Teaching clippy about revision control is not that hard.

[Manishearth]

I think this is out of scope for Clippy, at least the integration with VCSes

[shaleh]

I can understand that.

[theduke]

This might be somewhat controversial (mainly because this could be seen as out of scope for Clippy), but apart from a FIXME attribute, I'd actually love a lint that detects FIXME in comments.
If you run on CI you can ensure that you never merge a branch with pending FIXMEs.

Is this something that would be accepted?

[shaleh]

I am a fan of those @theduke. Emacs marks FIXME, TODO, and XXX in bold, bright colors for me.

[flip1995]

Is this something that would be accepted?

Yes, this could be implemented as a restriction lint.

[phansch]

It's worth noting that only doc comments are accessible to Clippy.
(Unless we parse all source files ourselves, but that's not a good idea for various reasons)

[theduke]

@phansch that sadly means the idea is void, since most FIXME s would be in non-doc comments.

[martin-t]

Something similar could be achieved using rustfmt's report_fixme. You should be able to set it to "Unnumbered", to force people to create issues for FIXMEs, then filter your project's issues by date.

The question is how to get more projects to discover and use it.

It's worth noting that only doc comments are accessible to Clippy.
(Unless we parse all source files ourselves, but that's not a good idea for various reasons)

@phansch Then how does rustfmt get access to comments? It seems to just use libsyntax,

[flip1995]

IIUC, rustfmt checks the text of files directly to find FIXMEs/TODOs, without parsing the file. This is not something Clippy should do IMO.

I think we can close this, since rustfmt implements this already?