Unsafe is no longer necessary as of rustc 1.34 #488
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Our current MSRV is 1.32.0 😞 However I will keep the issue open so we can update the relevant code when we get to it |
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We've just bumped our MSRV to Would anybody like to submit a PR for this? |
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Previously, to_fields and to_fields_le used unsafe to convert a &[u8] into a &[u8; 8]. Now that we're only supporting Rust versions where TryInto is stable, we can use try_into().unwrap() instead, making uuid entirely safe Rust. In release mode, the compiler detects that the slice will always be the correct size, so try_into can never fail. Thus, the unwrap is optimized out and we end up with the exact same assembly as the unsafe block. Godbolt output showing the resulting assembly: https://godbolt.org/z/nWxT6W Closes uuid-rs#488.
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507: Use TryInto to avoid unsafe. r=kinggoesgaming a=Gaelan
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**I'm submitting a(n)** refactor
# Description
Previously, to_fields and to_fields_le used unsafe to convert a &[u8] into a &[u8; 8]. Now that we're only supporting Rust versions where TryInto is stable, we can use try_into().unwrap() instead, making uuid entirely safe Rust.
In release mode, the compiler detects that the slice will always be the correct size, so try_into can never fail. Thus, the unwrap
is optimized out and we end up with the exact same assembly as the unsafe block.
Godbolt output showing the resulting assembly: https://godbolt.org/z/nWxT6W
# Motivation
Makes UUID entirely safe Rust.
With this PR,
# Tests
All existing tests pass. Doesn't add any new functionality, so that should be sufficient. Assuming the Godbolt test is consistent with what happens in the context of the larger crate, this shouldn't change the resulting binary at all.
# Related Issue(s)
Closes #488.
Co-authored-by: Gaelan Steele <gbs@canishe.com>
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This code (and another identical line in the same file) uses unsafe to convert a
&[u8]to a&[u8; 8]:uuid/src/lib.rs
Line 360 in f177d20
From Rust 1.34 and on (before that, TryFrom wasn't stable), the following code compiles to the exact same assembly as the code above:
Tested with rustc 1.34 and 1.45.2 on godbolt.org, with
-O.The
try_intoversion is simpler and doesn't use unsafe, so it'd probably be a good idea to switch to that once support for Rust 1.32/33 is dropped.The text was updated successfully, but these errors were encountered: