Merge pull request #96 from rust-random/push-yxqmsxlmnwqq

dhardy · web-flow · commit 108835817c73 · 2026-02-08T14:21:32.000Z
Update for rand v0.10
diff --git a/src/SUMMARY.md b/src/SUMMARY.md
@@ -29,6 +29,7 @@
     - [Updating to 0.7](update-0.7.md)
     - [Updating to 0.8](update-0.8.md)
     - [Updating to 0.9](update-0.9.md)
+    - [Updating to 0.10](update-0.10.md)
 
 - [Contributing](contributing.md)
     - [Documentation](contrib-doc.md)
diff --git a/src/guide-data.md b/src/guide-data.md
@@ -1,8 +1,7 @@
 # Random data
 
 ```rust
-# extern crate rand;
-# use rand::RngCore;
+# use rand::Rng;
 # fn main() {
 // get some random data:
 let mut data = [0u8; 8];
diff --git a/src/guide-dist.md b/src/guide-dist.md
@@ -94,7 +94,7 @@ Lets go over the distributions by type:
 -   For enums, you have to implement uniform sampling yourself. For example, you
     could use the following approach:
     ```rust,noplayground
-    # use rand::{Rng, distr::{Distribution, StandardUniform}};
+    # use rand::{Rng, RngExt, distr::{Distribution, StandardUniform}};
     pub enum Food {
         Burger,
         Pizza,
diff --git a/src/guide-gen.md b/src/guide-gen.md
@@ -7,17 +7,15 @@ This section concerns theory; see also the chapter on
 [random number generators](guide-rngs.md).
 
 ```rust
-# extern crate rand;
-# extern crate rand_chacha;
-use rand::{Rng, SeedableRng};
+use rand::{RngExt, SeedableRng};
 
 # fn main() {
 // prepare a non-deterministic random number generator:
 let mut rng = rand::rng();
 println!("{}", rng.random::<i32>()); // prints an unknown value
 
 // prepare a deterministic generator:
-let mut rng = rand_chacha::ChaCha8Rng::seed_from_u64(123);
+let mut rng = rand::rngs::ChaCha8Rng::seed_from_u64(123);
 println!("{}", rng.random::<i32>()); // prints -416273517
 # }
 ```
diff --git a/src/guide-parallel.md b/src/guide-parallel.md
@@ -108,7 +108,7 @@ non-deterministic simulation too.
 
 ```rust
 use rand::distr::{Distribution, Uniform};
-use rand_chacha::{rand_core::SeedableRng, ChaCha8Rng};
+use rand::{SeedableRng, rngs::ChaCha8Rng};
 use rayon::prelude::*;
 
 static SEED: u64 = 0;
diff --git a/src/guide-rngs.md b/src/guide-rngs.md
@@ -247,9 +247,17 @@ seeded with a secure random key. Should the key be known or guessable, all
 output of the CSPRNG is easy to guess. This implies that the seed should
 come from a trusted source; usually either the OS or another CSPRNG. For this
 purpose, we recommend using the [`getrandom`] crate which interfaces the OS's
-secure random interface. [`SeedableRng::from_os_rng`] is a wrapper around
-[`getrandom`] for convenience. Alternatively, using a user-space CSPRNG such as
-[`ThreadRng`] for seeding should be sufficient.
+secure random interface. Alternatively, using a user-space CSPRNG such as
+[`rand::make_rng()`] or [`ThreadRng`] for seeding should be sufficient. In code:
+```rust
+use rand::{rngs::ChaCha12Rng, rngs::SysRng, SeedableRng};
+
+/// Seed explicitly from SysRng:
+let mut rng1 = ChaCha12Rng::try_from_rng(&mut SysRng).unwrap();
+
+/// Seed from ThreadRng (or SysRng if ThreadRng is not available):
+let mut rng2: ChaCha12Rng = rand::make_rng();
+```
 
 Further, it should be obvious that the internal state of a CSPRNG must be
 kept secret. With that in mind, our implementations do not provide direct
@@ -335,5 +343,5 @@ by P. Hellekalek.
 [NIST]: https://www.nist.gov/
 [ECRYPT]: http://www.ecrypt.eu.org/
 [`getrandom`]: https://docs.rs/getrandom/
-[`SeedableRng::from_os_rng`]: https://docs.rs/rand/latest/rand/trait.SeedableRng.html#method.from_os_rng
 [zeroize]: https://crates.io/crates/zeroize
+[`rand::make_rng()`]: https://docs.rs/rand/latest/rand/fn.make_rng.html
diff --git a/src/guide-seeding.md b/src/guide-seeding.md
@@ -25,16 +25,14 @@ PRNGs may be seeded directly from such a value with [`SeedableRng::from_seed`].
 
 ### Fresh entropy
 
-Using a fresh seed (direct from the OS) is easy using [`SeedableRng::from_os_rng`]:
+Using a fresh seed is easy using [`rand::make_rng()`]:
 
 ```rust,editable
-# extern crate rand;
-# extern crate rand_chacha;
 use rand::prelude::*;
-use rand_chacha::ChaCha20Rng;
+use rand::rngs::ChaCha20Rng;
 
 fn main() {
-    let mut rng = ChaCha20Rng::from_os_rng();
+    let mut rng: ChaCha20Rng = rand::make_rng();
     println!("{}", rng.random_range(0..100));
 }
 ```
@@ -47,7 +45,6 @@ Quite obviously, another RNG may be used to fill a seed. We provide a
 convenience method for this:
 
 ```rust,editable
-# extern crate rand;
 use rand::prelude::*;
 
 fn main() {
@@ -60,10 +57,8 @@ But, say you want to save a key and use it later. For that you need to be a
 little bit more explicit:
 
 ```rust,editable
-# extern crate rand;
-# extern crate rand_chacha;
 use rand::prelude::*;
-use rand_chacha::ChaCha8Rng;
+use rand::rngs::ChaCha8Rng;
 
 fn main() {
     let mut seed: <ChaCha8Rng as SeedableRng>::Seed = Default::default();
@@ -91,10 +86,8 @@ number while providing good bit-avalanche (so that two similar numbers such as
 0 and 1 translate to very different seeds and independent RNG sequences).
 
 ```rust,editable
-# extern crate rand;
-# extern crate rand_chacha;
 use rand::prelude::*;
-use rand_chacha::ChaCha8Rng;
+use rand::rngs::ChaCha8Rng;
 
 fn main() {
     let mut rng = ChaCha8Rng::seed_from_u64(2);
@@ -150,7 +143,7 @@ function such as Argon2 must be used.
 [`SeedableRng::from_seed`]: https://docs.rs/rand_core/latest/rand_core/trait.SeedableRng.html#tymethod.from_seed
 [`SeedableRng::from_rng`]: https://docs.rs/rand_core/latest/rand_core/trait.SeedableRng.html#method.from_rng
 [`SeedableRng::seed_from_u64`]: https://docs.rs/rand_core/latest/rand_core/trait.SeedableRng.html#method.seed_from_u64
-[`SeedableRng::from_os_rng`]: https://docs.rs/rand_core/latest/rand_core/trait.SeedableRng.html#method.from_os_rng
 [`XorShiftRng`]: https://docs.rs/rand_xorshift/latest/rand_xorshift/struct.XorShiftRng.html
 [`ChaCha8Rng`]: https://docs.rs/rand_chacha/latest/rand_chacha/struct.ChaCha8Rng.html
 [`rand_seeder`]: https://github.com/rust-random/seeder/
+[`rand::make_rng()`]: https://docs.rs/rand/latest/rand/fn.make_rng.html
diff --git a/src/guide-start.md b/src/guide-start.md
@@ -11,7 +11,6 @@ cargo add rand --features small_rng
 
 Now, paste the following into `src/main.rs`:
 ```rust
-# extern crate rand;
 use rand::prelude::*;
 
 fn main() {
diff --git a/src/guide-test-fn-rng.md b/src/guide-test-fn-rng.md
@@ -3,9 +3,9 @@
 Occasionally a function that uses random number generators might need to be tested. For functions that need to be tested with test vectors, the following approach might be adapted:
 
 ```rust
-use rand::{TryCryptoRng, rngs::OsRng};
+use rand::{TryCryptoRng, rngs::SysRng};
 
-pub struct CryptoOperations<R: TryCryptoRng = OsRng> {
+pub struct CryptoOperations<R: TryCryptoRng = SysRng> {
     rng: R
 }
 
@@ -30,7 +30,7 @@ impl<R: TryCryptoRng> CryptoOperations<R> {
 }
 
 fn main() {
-    let rng = OsRng;
+    let rng = SysRng;
     let mut crypto_ops = <CryptoOperations>::new(rng);
 
     let mut secret: [u8; 8] = *b"\x00\x01\x02\x03\x04\x05\x06\x07";
diff --git a/src/guide-values.md b/src/guide-values.md
@@ -38,8 +38,7 @@ Finally, it has a function to sample from arbitrary distributions:
 Examples:
 
 ```rust
-# extern crate rand;
-use rand::Rng;
+use rand::RngExt;
 # fn main() {
 let mut rng = rand::rng();
 
@@ -58,7 +57,6 @@ println!("roll = {}", rng.random_range(1..=6));
 
 Additionally, the [`random`] function is a short-cut to [`Rng::random`] on the [`rng()`]:
 ```rust
-# extern crate rand;
 # use rand::Rng;
 # fn main() {
 println!("Tossing a coin...");
@@ -92,8 +90,7 @@ according to reasonable logic:
 
 Given that, we can implement the [`StandardUniform`] distribution for our own types:
 ```rust
-# extern crate rand;
-use rand::Rng;
+use rand::{Rng, RngExt};
 use rand::distr::{Distribution, StandardUniform, Uniform};
 use std::f64::consts::TAU; // = 2π
 
diff --git a/src/quick-start.md b/src/quick-start.md
@@ -6,7 +6,6 @@ or the [guide].
 Lets kick things off with an example
 
 ```rust,editable
-# extern crate rand;
 // import commonly used items from the prelude:
 use rand::prelude::*;
 
@@ -82,12 +81,10 @@ See the [RNGs] section for more RNGs, but avoid `SmallRng` and `StdRng` if you
 care about reproducible results.
 
 ```rust,editable
-# extern crate rand;
-# extern crate rand_chacha;
-use rand::{Rng, SeedableRng};
+use rand::{rngs::ChaCha8Rng, RngExt, SeedableRng};
 
 fn main() {
-    let mut rng = rand_chacha::ChaCha8Rng::seed_from_u64(10);
+    let mut rng = ChaCha8Rng::seed_from_u64(10);
     println!("Random f32: {}", rng.random::<f32>());
 }
 ```
diff --git a/src/update-0.10.md b/src/update-0.10.md
@@ -0,0 +1,88 @@
+# Updating to 0.10
+
+In the following, instructions are provided for porting your code from
+`rand 0.9` to `rand 0.10`.
+
+The following is a migration guide focussing on potentially-breaking changes. For a full list of changes, see the relevant changelogs:
+
+-   [CHANGELOG.md](https://github.com/rust-random/rand/blob/master/CHANGELOG.md).
+-   [rand_core/CHANGELOG.md](https://docs.rs/crate/rand_core/latest/source/CHANGELOG.md).
+
+
+## [Try]Rng traits
+
+The `rand_core` traits `RngCore, TryRngCore` were renamed to `Rng, TryRng` and the `rand` trait `Rng` to `RngExt` respectively.
+
+The relationship between these traits also changed; previously, every `R: RngCore` implemented `TryRngCore` but otherwise the two traits were independent; now `Rng: TryRng<Error = Infallible>` and every `R: TryRng<Error = Infallible> + ?Sized` implements `Rng`.
+
+Further, while we previously implemented `R: RngCore` for every `R: DerefMut where R::Target: RngCore`, we were unable to do so due to conflicting-trait errors (solving this would have required specialization or negative trait bounds). Now, we implement `R: TryRng` for every `R: DerefMut where R::Target: TryRng` which thus implies `R: Rng` for every `R: DerefMut where R::Target: Rng`.
+
+The biggest impact here is that infallible PRNGs must implement `TryRng` with `Error = Infallible` instead of implementing `RngCore`.
+
+Users of `rand` will often need to import `rand::RngExt` may need to migrate from `R: RngCore` to `R: Rng` (noting that where `R: Rng` was previously used it may be preferable to keep `R: Rng` even though the direct replacement would be `R: RngExt`; the two bounds are equivalent for `R: Sized`).
+
+
+## SysRng
+
+`rand_core::OsRng` has been replaced with `getrandom::SysRng` (also available as `rand::rngs::SysRng`).
+
+The methods `SeedableRng::from_os_rng` and `try_from_os_rng` have thus been removed. [`rand::make_rng()`] is provided as a partial replacement; otherwise use `SomeRng::try_from_rng(&mut SysRng).unwrap()`.
+
+
+## PRNGs
+
+`StdRng` is now provided by `chacha20` instead of `rand_chacha`. For the time being both packages are maintained, but `rand_chacha` is likely to be discontinued in the future. The `ChaCha{8,12,20}Rng` types are a direct replacement for the like-named `rand_chacha` types; these maintain reproducibility of output and have a similar API.
+
+Note that `rand::rngs` now provides several named PRNGs, making it simpler to write [reproducible](crate-reprod.md) code: `ChaCha{8,12,20}Rng`, `Xoshiro{128,256}PlusPlus`.
+
+Other PRNG crates have been updated with minimal changes (though this may not remain the case indefinitely; see [rngs#98](https://github.com/rust-random/rngs/issues/98)). One new crate has been added: [rand_sfc](https://docs.rs/rand_sfc/latest/rand_sfc/).
+
+### Clone and serialization support
+
+`StdRng` and `ChaCha{8,12,20}Rng` no longer implement `Clone` or the [serde] traits. This was a deliberate choice to prevent accidental key-stream duplication or persisting to external storage. Note that it remains possible to clone or serialize these RNGs by reconstructing a new instance with the same key, then setting the stream (if applicable) and word position. For example:
+```rust,editable
+use rand::{rngs::ChaCha8Rng, Rng, SeedableRng};
+
+let mut rng1: ChaCha8Rng = rand::make_rng();
+let _ = rng1.next_u64();
+
+let mut rng2 = ChaCha8Rng::from_seed(rng1.get_seed());
+rng2.set_stream(rng1.get_stream());
+rng2.set_word_pos(rng1.get_word_pos());
+
+assert_eq!(rng1.next_u64(), rng2.next_u64());
+```
+
+
+## Other changes
+
+`TryRngCore::read_adapter` was replaced with `rand::RngReader`.
+
+### ReseedingRng
+
+`ReseedingRng` has been removed without replacement since, as far as we have been able to discern, `ThreadRng` is the only important use-case. We have thus opted to move its functionality into `ThreadRng` as an implementation detail.
+
+
+## Dependencies
+
+Rand crates now require **`rustc`** version 1.85.0 or later.
+
+The dependency on **`getrandom`** was bumped to version 0.4. See [the getrandom CHANGELOG](https://github.com/rust-random/getrandom/blob/master/CHANGELOG.md).
+
+### Features
+
+Feature flags:
+
+-   `os_rng` was renamed to `sys_rng`
+-   `thread_rng`, `std_rng` and `sys_rng` are no longer enabled by default (TODO: this is not yet confirmed)
+-   `small_rng` has been removed; its functionality is always available
+-   `chacha` is a new flag, enabling `rand::rngs::ChaCha{8,12,20}Rng`
+
+
+## Reproducibility
+
+There are no known value-breaking changes to `rand` in v0.10.
+
+
+[serde]: https://serde.rs/
+[`rand::make_rng()`]: https://docs.rs/rand/latest/rand/fn.make_rng.html
diff --git a/src/update-0.5.md b/src/update-0.5.md
@@ -75,7 +75,8 @@ any type supporting `SeedableRng`, and provides construction from fresh, strong
 entropy:
 
 ```rust,noplayground
-use rand_0_5::{ChaChaRng, FromEntropy};
+# extern crate rand_0_5 as rand;
+use rand::{ChaChaRng, FromEntropy};
 
 let mut rng = ChaChaRng::from_entropy();
 ```
@@ -121,7 +122,8 @@ A new `Error` type has been added, designed explicitly for no-std compatibility,
 simplicity, and enough flexibility for our uses (carrying a `cause` when
 possible):
 ```rust,noplayground
-# use rand_0_5::ErrorKind;
+# extern crate rand_0_5 as rand;
+# use rand::ErrorKind;
 pub struct Error {
     pub kind: ErrorKind,
     pub msg: &'static str,
@@ -183,10 +185,9 @@ The method `ChaChaRng::set_counter` has been replaced by two new methods,
 method may be emulated as follows:
 
 ```rust,noplayground
-# extern crate rand;
-# extern crate rand_chacha;
+# extern crate rand_0_5 as rand;
 # use rand::prelude::*;
-# use rand_chacha::ChaChaRng;
+# use rand_chacha_0_1::ChaChaRng;
 # fn main() {
 let lower = 88293;
 let higher = 9300932;
diff --git a/src/update-0.8.md b/src/update-0.8.md
@@ -53,9 +53,9 @@ let b: u32 = Standard.sample_iter(rng).next().unwrap();
 ```
 can be replaced with the following code:
 ```rust,noplayground
-# extern crate rand;
-# use rand_0_8::prelude::*;
-# use rand_0_8::distributions::Standard;
+# extern crate rand_0_8 as rand;
+# use rand::prelude::*;
+# use rand::distributions::Standard;
 # fn main () {
 let mut rng = thread_rng();
 let a: u32 = Standard.sample_iter(&mut rng).next().unwrap();
@@ -131,10 +131,10 @@ Several smaller changes occurred to rand distributions:
     ```
     With Rand 0.8, this is equivalent to the following:
     ```rust,noplayground
-    # extern crate rand;
-    # use rand_0_8::{distributions::Alphanumeric, Rng};
+    # extern crate rand_0_8 as rand;
+    # use rand::{distributions::Alphanumeric, Rng};
     # fn main() {
-    # let mut rng = rand_0_8::thread_rng();
+    # let mut rng = rand::thread_rng();
     let chars: String = std::iter::repeat(())
         .map(|()| rng.sample(Alphanumeric))
         .map(char::from)
diff --git a/src/update-0.9.md b/src/update-0.9.md
@@ -6,7 +6,7 @@ In the following, instructions are provided for porting your code from
 The following is a migration guide focussing on potentially-breaking changes. For a full list of changes, see the relevant changelogs:
 
 -   [CHANGELOG.md](https://github.com/rust-random/rand/blob/master/CHANGELOG.md).
--   [rand_core/CHANGELOG.md](https://github.com/rust-random/rand/blob/master/rand_core/CHANGELOG.md).
+-   [rand_core/CHANGELOG.md](https://docs.rs/crate/rand_core/latest/source/CHANGELOG.md).
 -   [rand_distr/CHANGELOG.md](https://github.com/rust-random/rand/blob/master/rand_distr/CHANGELOG.md).
 
 ## Renamed functions and methods
diff --git a/tests/Cargo.toml b/tests/Cargo.toml
