Not aware of conditional path attribute

[anowell]

#[cfg_attr(feature="with-serde", path = "json-serde.rs")]
#[cfg_attr(feature="with-rustc-serialize", path = "json-rustc-serialize.rs")]
mod json;

results in this error preventing cargo fmt from completing:

error: file not found for module `json`
  --> /home/anowell/proj/algorithmia-rust/src/lib.rs:53:5
   |
53 | mod json;
   |     ^^^^
   |
   = help: name the file either json.rs or json/mod.rs inside the directory "/home/anowell/proj/algorithmia-rust/src"

I am able to work around it with:

#[cfg(feature="with-serde")]
#[path = "json-serde.rs"]
mod json;

#[cfg(feature="with-rustc-serialize")]
#[path = "json-rustc-serialize.rs"]
mod json;

[nrc]

Although Rustfmt really ought to cope with this, I'd recommend against using this pattern - I'd generally recommend against all uses of the path attribute.

[anowell]

In general, I also agree with avoiding path and sticking to the default path semantics. But I believe the snippet below is the closest equivalent without using path (where json is not exported outside of the crate, but is accessible everywhere within the crate). And I don't particularly find this easier to read or reason about, so IMO, I went from 3 lines to 6 lines to 10 lines without obvious gains - perhaps "one less concept to understand" (i.e. path) is a gain, but path seems to be the easiest concept to grok in these examples. ¯\_(ツ)_/¯

mod json {
    #[cfg(feature="with-serde")]
    mod json_serde;
    #[cfg(feature="with-serde")]
    pub use json_serde::*;

    #[cfg(feature="with-rustc-serialize")]
    mod json_rustc_serialize;
    #[cfg(feature="with-rustc-serialize")]
    pub use json_rustc_serialize::*;
}