Cargo rebuilds with include_str but not include_bytes

[nicholasbishop]

I encountered a strange difference in Cargo's behavior related to the include_str and include_bytes macros. It seems like include_str adds a build dependency on the included file but include_bytes does not.

Here's a simplified test case:

// main.rs

pub fn main() {
    const INPUT: &'static str = include_str!("input.txt");
    //const INPUT: &'static [u8] = include_bytes!("input.txt");

    println!("{:?}", INPUT);
}

This file lives in a minimal repo created with cargo new. There's an input.txt file in src/. Here's the full thing: https://github.com/nicholasbishop/cargo-includes-bug

I run cargo build and it compiles the program as expected. I modify input.txt and run cargo build. The program recompiles, which is nice.

Then I comment out the include_str! line and uncomment the include_bytes! line. I run cargo build and it recompiles as expected. Then I modify input.txt and run cargo build. The program does not recompile.

Tested with:

rustc 1.0.0-nightly (6b95d8bed 2015-04-09) (built 2015-04-10)

cargo 0.0.1-pre-nightly (471c519 2015-04-08) (built 2015-04-09)

(This started out in a StackOverflow question: http://stackoverflow.com/questions/29200914/how-can-i-tell-cargo-to-rebuild-when-a-file-included-with-the-include-bytes-macr)

[tomaka]

This is a problem with rustc.

include_str! adds a dependency with this function call, but include_bytes! doesn't.

[huonw]

Filed rust-lang/rust#24348 against rustc.

[alexcrichton]

Thanks for tracking this down @tomaka! Closing in favor of rust-lang/rust#24348.