Clarify recco to install as a soft dependency

On IRC it was mentioned that clippy is not meant to be installed as a hard dependency.
As it was, the README placed the hard dependency instructions first and did not
mention the recommendation, misleading users into making it a hard dependency. A
quick survey of the dependent crates on crates.io reveals the reach of this issue.
This commit is contained in:
Daniel S Poulin 2016-11-18 22:46:12 -05:00 committed by GitHub
parent 276e85b700
commit 5a415f67de

View File

@ -17,8 +17,41 @@ Table of contents:
## Usage
Since this is a tool for helping the developer of a library or application
write better code, it is recommended to include clippy as an optional
dependency.
As a general rule clippy will only work with the *latest* Rust nightly for now.
### Optional dependency
If you want to make clippy an optional dependency, you can do the following:
In your `Cargo.toml`:
```toml
[dependencies]
clippy = {version = "*", optional = true}
[features]
default = []
```
And, in your `main.rs` or `lib.rs`:
```rust
#![cfg_attr(feature="clippy", feature(plugin))]
#![cfg_attr(feature="clippy", plugin(clippy))]
```
Then build by enabling the feature: `cargo build --features "clippy"`
Instead of adding the `cfg_attr` attributes you can also run clippy on demand:
`cargo rustc --features clippy -- -Z no-trans -Z extra-plugins=clippy`
(the `-Z no trans`, while not neccessary, will stop the compilation process after
typechecking (and lints) have completed, which can significantly reduce the runtime).
### As a Compiler Plugin
Since stable Rust is backwards compatible, you should be able to
@ -97,34 +130,6 @@ cargo rustc -- -L /path/to/clippy_so -Z extra-plugins=clippy
*[Note](https://github.com/Manishearth/rust-clippy/wiki#a-word-of-warning):*
Be sure that clippy was compiled with the same version of rustc that cargo invokes here!
### Optional dependency
If you want to make clippy an optional dependency, you can do the following:
In your `Cargo.toml`:
```toml
[dependencies]
clippy = {version = "*", optional = true}
[features]
default = []
```
And, in your `main.rs` or `lib.rs`:
```rust
#![cfg_attr(feature="clippy", feature(plugin))]
#![cfg_attr(feature="clippy", plugin(clippy))]
```
Then build by enabling the feature: `cargo build --features "clippy"`
Instead of adding the `cfg_attr` attributes you can also run clippy on demand:
`cargo rustc --features clippy -- -Z no-trans -Z extra-plugins=clippy`
(the `-Z no trans`, while not neccessary, will stop the compilation process after
typechecking (and lints) have completed, which can significantly reduce the runtime).
## Configuration