Disable std feature by default in rand_core and rand_jitter

Implements #702
Resolves #645

Cargo.toml

@@ -46,9 +46,9 @@ members = [
 ]
 
 [dependencies]
-rand_core = { path = "rand_core", version = "0.3", default-features = false }
+rand_core = { path = "rand_core", version = "0.4" }
 rand_pcg = { path = "rand_pcg", version = "0.1" }
-rand_jitter = { path = "rand_jitter", version = "0.1", default-features = false }
+rand_jitter = { path = "rand_jitter", version = "0.1" }
 rand_os = { path = "rand_os", version = "0.1", optional = true  }
 # only for deprecations and benches:
 rand_isaac = { path = "rand_isaac", version = "0.1" }
@@ -84,4 +84,4 @@ autocfg = "0.1"
 all-features = true
 
 [patch.crates-io]
-rand_core = { path = "rand_core", version = "0.3", default-features = false }
+rand_core = { path = "rand_core", version = "0.4" }

rand_chacha/Cargo.toml

@@ -19,7 +19,7 @@ travis-ci = { repository = "rust-random/rand" }
 appveyor = { repository = "rust-random/rand" }
 
 [dependencies]
-rand_core = { path = "../rand_core", version = ">=0.2, <0.4", default-features=false }
+rand_core = { path = "../rand_core", version = "0.4" }
 
 [build-dependencies]
 autocfg = "0.1"

rand_core/CHANGELOG.md

@@ -4,6 +4,9 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/)
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [0.4.0] - 2019-01-24
+- Disable the `std` feature by default (#702)
+
 ## [0.3.0] - 2018-09-24
 - Add `SeedableRng::seed_from_u64` for convenient seeding. (#537)
 

rand_core/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "rand_core"
-version = "0.3.0"
+version = "0.4.0"
 authors = ["The Rand Project Developers", "The Rust Project Developers"]
 license = "MIT/Apache-2.0"
 readme = "README.md"
@@ -18,7 +18,6 @@ travis-ci = { repository = "rust-random/rand" }
 appveyor = { repository = "rust-random/rand" }
 
 [features]
-default = ["std"]
 std = ["alloc"]    # use std library; should be default but for above bug
 alloc = []  # enables Vec and Box support without std
 serde1 = ["serde", "serde_derive"] # enables serde for BlockRng wrapper

rand_core/README.md

@@ -44,13 +44,14 @@ The traits and error types are also available via `rand`.
 
 `rand_core` supports `no_std` and `alloc`-only configurations, as well as full
 `std` functionality. The differences between `no_std` and full `std` are small,
-comprising `RngCore` support for `Box<R>` types where `R: RngCore`, as well as
+comprising `RngCore` support for `Box<R>` types where `R: RngCore`,
+`std::io::Read` support for types supporting `RngCore`, and
 extensions to the `Error` type's functionality.
 
-Due to [rust-lang/cargo#1596](https://github.com/rust-lang/cargo/issues/1596),
-`rand_core` is built without `std` support by default. Since features are
-unioned across the whole dependency tree, any crate using `rand` with its
-default features will also enable `std` support in `rand_core`.
+The `std` feature is *not enabled by default*. This is primarily to avoid build
+problems where one crate implicitly requires `rand_core` with `std` support and
+another crate requires `rand` *without* `std` support. However, the `rand` crate
+continues to enable `std` support by default, both for itself and `rand_core`.
 
 The `serde1` feature can be used to derive `Serialize` and `Deserialize` for RNG
 implementations that use the `BlockRng` or `BlockRng64` wrappers.

rand_hc/Cargo.toml

@@ -18,4 +18,4 @@ travis-ci = { repository = "rust-random/rand" }
 appveyor = { repository = "rust-random/rand" }
 
 [dependencies]
-rand_core = { path = "../rand_core", version = ">=0.2, <0.4", default-features=false }
+rand_core = { path = "../rand_core", version = "0.4" }

rand_isaac/Cargo.toml

@@ -21,7 +21,7 @@ appveyor = { repository = "rust-random/rand" }
 serde1 = ["serde", "serde_derive", "rand_core/serde1"]
 
 [dependencies]
-rand_core = { path = "../rand_core", version = "0.3", default-features=false }
+rand_core = { path = "../rand_core", version = "0.4" }
 serde = { version = "1", optional = true }
 serde_derive = { version = "^1.0.38", optional = true }
 

rand_jitter/CHANGELOG.md

@@ -4,5 +4,5 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/)
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
-## [0.1.0] - 2019-01-04
+## [0.1.0] - 2019-01-24
 Initial release.

rand_jitter/Cargo.toml

@@ -14,7 +14,7 @@ travis-ci = { repository = "rust-random/rand" }
 appveyor = { repository = "rust-random/rand" }
 
 [dependencies]
-rand_core = { path = "../rand_core", version = "0.3", default-features = false }
+rand_core = { path = "../rand_core", version = "0.4" }
 log = { version = "0.4", optional = true }
 
 [target.'cfg(any(target_os = "macos", target_os = "ios"))'.dependencies]
@@ -24,6 +24,4 @@ libc = "0.2"
 winapi = { version = "0.3", features = ["profileapi"] }
 
 [features]
-default = ["std"]
-std = []
-
+std = ["rand_core/std"]

rand_jitter/README.md

@@ -22,6 +22,12 @@ Links:
 -   [API documentation (docs.rs)](https://docs.rs/rand_jitter)
 -   [Changelog](CHANGELOG.md)
 
+## Features
+
+This crate has optional `std` support which is *disabled by default*;
+this feature is required to provide the `JitterRng::new` function;
+without `std` support a timer must be supplied via `JitterRng::new_with_timer`.
+
 ## Quality testing
 
 `JitterRng::new()` has build-in, but limited, quality testing, however

rand_jitter/tests/mod.rs

@@ -2,8 +2,10 @@ extern crate rand_jitter;
 extern crate rand_core;
 
 use rand_jitter::JitterRng;
+#[cfg(feature = "std")]
 use rand_core::RngCore;
 
+#[cfg(feature = "std")]
 #[test]
 fn test_jitter_init() {
     // Because this is a debug build, measurements here are not representive

rand_os/Cargo.toml

@@ -15,7 +15,7 @@ travis-ci = { repository = "rust-random/rand" }
 appveyor = { repository = "rust-random/rand" }
 
 [dependencies]
-rand_core = { path = "../rand_core", version = "0.3", default-features = false }
+rand_core = { path = "../rand_core", version = "0.4", features = ["std"] }
 log = { version = "0.4", optional = true }
 
 [target.'cfg(unix)'.dependencies]

rand_pcg/Cargo.toml

@@ -22,7 +22,7 @@ appveyor = { repository = "rust-random/rand" }
 serde1 = ["serde", "serde_derive"]
 
 [dependencies]
-rand_core = { path = "../rand_core", version = "0.3", default-features=false }
+rand_core = { path = "../rand_core", version = "0.4" }
 serde = { version = "1", optional = true }
 serde_derive = { version = "^1.0.38", optional = true }
 

rand_xorshift/Cargo.toml

@@ -21,7 +21,7 @@ appveyor = { repository = "rust-random/rand" }
 serde1 = ["serde", "serde_derive"]
 
 [dependencies]
-rand_core = { path = "../rand_core", version = ">=0.2, <0.4", default-features=false }
+rand_core = { path = "../rand_core", version = "0.4" }
 serde = { version = "1", optional = true }
 serde_derive = { version = "^1.0.38", optional = true }
 

rand_xoshiro/Cargo.toml

@@ -13,7 +13,7 @@ categories = ["algorithms"]
 
 [dependencies]
 byteorder = { version = "1", default-features=false }
-rand_core = { path = "../rand_core", version = "0.3", default-features=false }
+rand_core = { path = "../rand_core", version = "0.4" }
 
 [dev-dependencies]
 rand = { path = "..", version = "0.6", default-features=false }  # needed for doctests