rand_core and no_std builds

[dhardy]

criterion.rs/Cargo.toml

Line 30 in 3117ef6

rand_core = "0.3"

Criterion implicitly requires the std feature of rand_core, though doesn't appear to need it. This appears to be breaking builds.

While we may disable this feature by default in the future, you could help users now by disabling default features on rand_core.

[bheisler]

Oh, good grief. I really can't do anything without breaking somebody's code.

Right, I'll have to publish an 0.2.9 later to fix this. Thanks for letting me know!

[bheisler]

OK, I've committed the change to disable the default features of rand-core. Can you confirm that fixes it, before I publish a new version?

[dhardy]

On which branch? I don't see that change on master.

@hdevalence reported the issue — can you test?

In other news, I have a PR to no longer enable std by default, but it won't take affect until people update to version 0.4 (not yet released).

[bheisler]

facepalm

My bad, I forgot to push the commit. Try it now.

[hdevalence]

Hi, thanks for digging into this! I just ran these tests on my machine, so I think that this does fix the problem:

~/c/x25519-dalek (develop|✔) $ cargo build --features="u32_backend nightly" --no-default-features
    Updating crates.io index
   Compiling rand v0.6.4                                                                                                 
error[E0277]: the trait bound `rngs::jitter::TimerError: std::error::Error` is not satisfied                             
   --> /home/hdevalence/.cargo/registry/src/github.com-1ecc6299db9ec823/rand-0.6.4/src/rngs/jitter.rs:267:9              
    |                                                                                                                    
267 |         Error::with_cause(ErrorKind::Unavailable,                                                                  
    |         ^^^^^^^^^^^^^^^^^ the trait `std::error::Error` is not implemented for `rngs::jitter::TimerError`          
    |                                                                                                                    
    = note: required because of the requirements on the impl of `core::convert::From<rngs::jitter::TimerError>` for `alloc::boxed::Box<(dyn std::error::Error + core::marker::Send + core::marker::Sync + 'static)>`
    = note: required because of the requirements on the impl of `core::convert::Into<alloc::boxed::Box<(dyn std::error::Error + core::marker::Send + core::marker::Sync + 'static)>>` for `rngs::jitter::TimerError`
    = note: required by `rand_core::Error::with_cause`                                                                   
                                                                                                                         
error: aborting due to previous error                                                                                    
                                                                                                                         
For more information about this error, try `rustc --explain E0277`.                                                      
error: Could not compile `rand`.                                                                                         

To learn more, run the command again with --verbose.
~/c/x25519-dalek (develop|✔) $ git stash pop
(snipped)
~/c/x25519-dalek (develop|✚1) $ git diff
diff --git a/Cargo.toml b/Cargo.toml
index 69b3aa0..3924b42 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -46,3 +46,6 @@ std = ["curve25519-dalek/std"]
 nightly = ["curve25519-dalek/nightly", "clear_on_drop/nightly"]
 u64_backend = ["curve25519-dalek/u64_backend"]
 u32_backend = ["curve25519-dalek/u32_backend"]
+
+[patch.crates-io]
+criterion = { git = "https://github.com/bheisler/criterion.rs" }
~/c/x25519-dalek (develop|✚1) $ cargo build --features="u32_backend nightly" --no-default-features
    Updating git repository `https://github.com/bheisler/criterion.rs`
    Finished dev [unoptimized + debuginfo] target(s) in 0.21s                                                            
~/c/x25519-dalek (develop|✚1) $ 

[bheisler]

Alright, I've published 0.2.9 with this fix.

[hdevalence]

Thanks for the help!

[dhardy]

Closing?

[king-11]

can criterion still work with no_std build if html_reports isn't required?