misleading warning if rustfmt is not handled by rustup

[matthiaskrgr]

I installed rustfmt-nightly via cargo install rustfmt-nightly.
When doing rustup update, I get a warning

warning: tool `rustfmt` is already installed, remove it from `/home/matthias/.cargo/bin`, then run `rustup update` to have rustup manage this tool.
warning: tool `cargo-fmt` is already installed, remove it from `/home/matthias/.cargo/bin`, then run `rustup update` to have rustup manage this tool.

which sounds like cargo uninstall rustfmt-nightly ; rustup update will automatically reinstall rustfmt via rustup however this does not seem to be the case.
Apparently I have to manually activate it via rustup component add --toolchain nightly rustfmt-preview.
Can we improve this warning message somehow, it's quite a bit misleading in my opinion. :/

[indygreg]

I just ran into this and was about to file the same bug. Here's the output from my terminal for context:

$ rustup update
...
info: downloading self-update

  stable-x86_64-unknown-linux-gnu unchanged - rustc 1.23.0 (766bd11c8 2018-01-01)
      beta-x86_64-unknown-linux-gnu updated - rustc 1.24.0-beta.11 (03f456d3c 2018-02-03)
   nightly-x86_64-unknown-linux-gnu updated - rustc 1.25.0-nightly (b8398d947 2018-02-11)

warning: tool `rustfmt` is already installed, remove it from `/home/gps/.cargo/bin`, then run `rustup update` to have rustup manage this tool.
warning: tool `cargo-fmt` is already installed, remove it from `/home/gps/.cargo/bin`, then run `rustup update` to have rustup manage this tool.

$ cargo uninstall rustfmt
    Removing /home/gps/.cargo/bin/cargo-fmt
    Removing /home/gps/.cargo/bin/rustfmt

$ rustup update
info: syncing channel updates for 'stable-x86_64-unknown-linux-gnu'
info: syncing channel updates for 'beta-x86_64-unknown-linux-gnu'
info: syncing channel updates for 'nightly-x86_64-unknown-linux-gnu'
info: checking for self-updates

   stable-x86_64-unknown-linux-gnu unchanged - rustc 1.23.0 (766bd11c8 2018-01-01)
     beta-x86_64-unknown-linux-gnu unchanged - rustc 1.24.0-beta.11 (03f456d3c 2018-02-03)
  nightly-x86_64-unknown-linux-gnu unchanged - rustc 1.25.0-nightly (b8398d947 2018-02-11)

At this point I was scratching my head as to how to actually install rustfmt and cargo-fmt with rustup. I'm still not sure to be honest :/

[daboross]

I'm pretty sure rustup will just want to own rustfmt and cargo-fmt whether or not it actually has binaries to back them with.

rustup update
rustup component add rustfmt-preview

works for me to install it most of the time (sometimes nightly versions don't have rustup at all..)

---

Regardless of that, it would be nice if rustup did not emit this warning when no toolchain has "rustfmt-preview" installed. If there's no chance that it can provide rustfmt/cargo-fmt, it should not complain about not being able to own those binaries.

[richardwhiuk]

This warning implies that it should just be removed - but surely a user should use cargo uninstall rustfmt instead?

[daboross]

If rustfmt was installed with cargo and you do want to replace it with the `rustup one, that's the right solution. Changing the message seems like it would be a different issue, though.

Ideally rustup shouldn't ask the user to remove it at all if none of the rustup toolchains have rustfmt installed in the first place.