Add a cargo checker for syntastic

[jlevesy]

Hi there !

As cargo check has been merged in cargo (see rust-lang/cargo#3296), and the current rustc checker is facing some issues with external crates (see #130), I gave a try implementing a cargo checker for syntastic.

And here is the result. Please note it is my first time writing a syntastic checker, and I'm relatively new to the rust ecosystem, consequently I might have made mistakes, so any feedback will be greatly appreciated !

It currently works with cargo 0.16.0 nightly.

Thanks !

[rust-highfive]

Thanks for the pull request, and welcome! The Rust team is excited to review your changes, and you should hear from @steveklabnik (or someone else) soon.

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[rhys-vdw]

Hey @jlevesy, I'm experiencing the same issue as #130 (I believe). I'm installed your branch but am not seeing a difference. Should cargo appear in the list of available checkers on a call to SyntasticInfo? (I have only a vague understanding of how Syntastic works, excuse my ignorance.)

[jlevesy]

Hey @rhys-vdw, thanks for giving a try !

cargo is indeed supposed to appear as an available checker.
What version of cargo are you using ?

[rhys-vdw]

I had done a totally fresh rustup install in case that was the issue. I'm on:

cargo 0.15.0-nightly (298a012 2016-12-20)

:SyntasticInfo output:

Syntastic version: 3.8.0-14 (Vim 704, Neovim, Darwin)                                                                                                                                                                                             
Info for filetype: rust                                                                                                                                                                                                                           
Global mode: passive                                                                                                                                                                                                                              
Active filetypes: javascript ruby rust                                                                                                                                                                                                            
Filetype rust is active                                                                                                                                                                                                                           
The current file will be checked automatically                                                                                                                                                                                                    
Available checker: rustc                                                                                                                                                                                                                          
Currently enabled checkers: -   

Also I went into my bundles and confirmed that syntax_checkers/rust/cargo.vim is present.

[jlevesy]

Hmmm, can you change your toolchain to nightly by runing rustup default nightly or rustup override set nightly (only to override toolchain for a specific project) ?

I think it will do the job, now cargo is 0.17.0-nightly.

Actually cargo check is embedded from version 0.16.0, below that you have to install an external plugin. So I chose to disable this checker, for cargo versions < 0.16.0 (see here).

[rhys-vdw]

Thanks @jlevesy. Working nicely! I can now see cargo in the available checkers, and have enabled it with:

let g:syntastic_rust_checkers = ['cargo']

[svenstaro]

I'm using this new checker locally and it's working really well. One thing I'd really like is if syntastic somehow automatically switched to the correct checker (rustc for single rust files, cargo for projects with a Cargo.toml) but that might be out of scope. Anyway, this checker is good to go!

[hasufell]

Doesn't work for me. I get no errors and no reported problems with cargo as checker, although the syntax is completely broken. rustc still works (via syntastic), but has the mentioned bugs.

https://github.com/mckinnsb/rust.vim/blob/master/syntax_checkers/rust/cargo.vim This one works perfectly fine for me though.

[torkleyy]

👍 Should also work with stable Rust as of Rust 1.16

[drozdziak1]

Why isn't this merged yet?

[jlevesy]

Sorry, I was away from my computer for a few months...

@hasufell, can you give me your rustc, cargo, vim and Syntastic versions please ?
Thanks

[hcpl]

@jlevesy apparently, 'cwd': expand('%:p:h') here is what solved the problem for @hasufell (taken from https://github.com/mckinnsb/rust.vim/blob/master/syntax_checkers/rust/cargo.vim#L40).

The current version doesn't work if you open a file from outside of the project it resides, because:

• cargo check needs to be called within the project,
• but Syntastic inherits vim environment when SyntasticMake is called.

[jlevesy]

Indeed, thank you for the review.

[hasufell]

yes, that works

[jacwah]

This seems like a great patch! It's essential to any Vim user actually -- the rustc formatter is very limited. I'm currently testing it out, and the checker has worked well so far.

[snboisen]

What prevents this from being merged? Anything we can do to help? The rustc checker is useless for cargo-based projects and I would expect that to be the overwhelming majority of projects?

[steveklabnik]

What prevents this from being merged?

1. I don't use syntastic
2. there are tons and tons of comments that I don't know how to evaluate

so, I've been kinda paralyzed. However, it seems this does work for lots of people, so I'm just going to merge it, and if it breaks stuff, well, people can send in new PRs to fix them.

Sorry to everyone in this thread for not taking this on sooner, as I've said elsewhere, if people want to help maintain rust.vim, please get in touch.