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Portability fixes #1469

Merged
merged 8 commits into from
Jul 23, 2024
Merged

Portability fixes #1469

merged 8 commits into from
Jul 23, 2024

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dhardy
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@dhardy dhardy commented Jul 18, 2024

  • Added a CHANGELOG.md entry

Summary

Fixes some of the smaller issues noted here. Specifically:

  • Fix portability of choose_multiple_array
  • Fix portability of rand::distributions::Slice

Further, this makes it more explicit which target_pointer_width sizes SmallRng backends are intended to support (the 16-bit choice is not intended to be optimal).

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It may be worth to add a build-only CI job for a 16-bit target to prevent regressions in future.

@@ -10,10 +10,10 @@

use rand_core::{RngCore, SeedableRng};

#[cfg(any(target_pointer_width = "32", target_pointer_width = "16"))]
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Why change it from not(target_pointer_width = "64")? Even with hypothetical 128-bit targets it's better to use Xoshiro128++ than to break builds. Alternatively, it's worth to at least add a compile_error! stating that we support only 16, 32, and 64 bit targets.

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  1. Because this is explicit about what is supported and recommended
  2. Effectively it is a compile error
  3. I don't care about theoretical targets. If people want to target 16- or 128-bits on rand, they can submit patches.

#[cfg(feature = "alloc")]
use alloc::string::String;

#[cfg(not(any(target_pointer_width = "32", target_pointer_width = "64")))]
const _: () = assert!(false, "unsupported pointer width");
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Why not use compile_error! here? Also, why can't we use UniformSize::U32 on 16-bit targets?

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  1. I forgot about it — I'll switch to compile_error!
  2. Dependencies don't compile and it seems like no-one cares much about 16-bit (Supported target_pointer_width: 32, 64-bit only? #1468), so there's no point wasting time here.

Comment on lines +20 to +24
enum UniformUsize {
U32(Uniform<u32>),
#[cfg(target_pointer_width = "64")]
U64(Uniform<u64>),
}
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As with gen_index, this should probably be exposed somehow (left for a future PR).

@dhardy dhardy added the D-review Do: needs review label Jul 20, 2024
@dhardy dhardy requested a review from newpavlov July 23, 2024 10:00
@dhardy dhardy merged commit 605476c into rust-random:master Jul 23, 2024
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@dhardy dhardy deleted the portability-fixes branch July 23, 2024 13:01
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2 participants