Port rand to CloudABI.

[EdSchouten]

CloudABI has a special system call, random_get(), that can be used to
obtain random data from the environment (the kernel, emulator, etc). We
can invoke this system call by making use of the cloudabi crate.

[EdSchouten]

I suspec that the test failure is not caused by this change specifically. Probably something wrong with the build environment?

[dhardy]

Cargo not found. I've seen that before; it seems Travis just fails sometimes. Restarted that build.

I don't know anything about CloudABI. Is there some way we can test code for this platform?

[EdSchouten]

Hey! Thanks for responding so quickly!

CloudABI is a strongly sandboxed UNIX-like runtime environment. Right now there is native support for running these executables on FreeBSD, experimental native support for Linux and NetBSD, and a userspace emulator that works on virtually any operating system out there (e.g., macOS).

Right now I'm still working on getting support for CloudABI integrated into Rust properly. I stumbled upon this build failure, because libstd (as built by ./x.py test) has a dependency on this crate. In other words: it's a big of a chicken-and-egg problem. I can't offer any ways of doing automated testing, as there is no version of Rust that supports CloudABI out of the box yet. Without this change, there is no way to build/test Rust for CloudABI.

In the meantime I am building a Docker container image that can be used to do automated tests for the main Rust codebase. I suspect that we may be able to reuse something like this to also run tests for rand.

[dhardy]

Well, this certainly sounds like an interesting project!

I believe libstd has an internal copy of OsRng and doesn't depend on this rand. (Or if you are using rand, let me know which version; 0.3 is the old stable, 0.4 the new stable, and master is for the upcoming 0.5 so won't be released so soon.)

[EdSchouten]

That's right. It looks like it's not that libstd depends on rand to build. It's just that libstd, liballoc and a couple of other libraries have rand as a development dependency, likely for automated tests and the likes. From Cargo.toml:

[dev-dependencies]
rand = "0.3"

I guess it makes sense to merge this change both to master and the 0.4 branch, right? Once this change makes it into a release, I can send out a pull request to rust/ to update from the version it uses right now (0.3.19) to 0.4.x.

[dhardy]

Yes, that makes sense. This is going to conflict with #225; I can sort that out though.

[dhardy]

#225 is now merged, could you please update this with compatible error-handling?

[EdSchouten]

Done! \o/