mirror of
https://github.com/rust-lang/rust-clippy
synced 2024-12-01 00:49:30 +00:00
49319b4206
set_len(0) does not create uninitialized elements. Fixes a false positive with
the following pattern:
fn copy_slice_into_vec(dst: &mut Vec<u8>, src: &[u8]) {
dst.reserve(src.len().saturating_sub(dst.len()));
unsafe {
dst.set_len(0);
std::ptr::copy_nonoverlapping(src.as_ptr(), dst.as_mut_ptr(), src.len());
dst.set_len(src.len());
}
}
100 lines
2.4 KiB
Rust
100 lines
2.4 KiB
Rust
#![warn(clippy::uninit_vec)]
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use std::mem::MaybeUninit;
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#[derive(Default)]
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struct MyVec {
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vec: Vec<u8>,
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}
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fn main() {
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// with_capacity() -> set_len() should be detected
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let mut vec: Vec<u8> = Vec::with_capacity(1000);
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unsafe {
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vec.set_len(200);
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}
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// reserve() -> set_len() should be detected
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vec.reserve(1000);
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unsafe {
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vec.set_len(200);
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}
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// new() -> set_len() should be detected
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let mut vec: Vec<u8> = Vec::new();
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unsafe {
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vec.set_len(200);
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}
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// default() -> set_len() should be detected
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let mut vec: Vec<u8> = Default::default();
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unsafe {
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vec.set_len(200);
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}
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let mut vec: Vec<u8> = Vec::default();
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unsafe {
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vec.set_len(200);
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}
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// test when both calls are enclosed in the same unsafe block
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unsafe {
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let mut vec: Vec<u8> = Vec::with_capacity(1000);
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vec.set_len(200);
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vec.reserve(1000);
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vec.set_len(200);
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}
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let mut vec: Vec<u8> = Vec::with_capacity(1000);
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unsafe {
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// test the case where there are other statements in the following unsafe block
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vec.set_len(200);
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assert!(vec.len() == 200);
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}
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// handle vec stored in the field of a struct
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let mut my_vec = MyVec::default();
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my_vec.vec.reserve(1000);
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unsafe {
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my_vec.vec.set_len(200);
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}
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my_vec.vec = Vec::with_capacity(1000);
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unsafe {
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my_vec.vec.set_len(200);
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}
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// Test `#[allow(...)]` attributes on inner unsafe block (shouldn't trigger)
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let mut vec: Vec<u8> = Vec::with_capacity(1000);
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#[allow(clippy::uninit_vec)]
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unsafe {
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vec.set_len(200);
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}
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// MaybeUninit-wrapped types should not be detected
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unsafe {
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let mut vec: Vec<MaybeUninit<u8>> = Vec::with_capacity(1000);
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vec.set_len(200);
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let mut vec: Vec<(MaybeUninit<u8>, MaybeUninit<bool>)> = Vec::with_capacity(1000);
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vec.set_len(200);
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let mut vec: Vec<(MaybeUninit<u8>, [MaybeUninit<bool>; 2])> = Vec::with_capacity(1000);
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vec.set_len(200);
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}
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// known false negative
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let mut vec1: Vec<u8> = Vec::with_capacity(1000);
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let mut vec2: Vec<u8> = Vec::with_capacity(1000);
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unsafe {
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vec1.set_len(200);
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vec2.set_len(200);
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}
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// set_len(0) should not be detected
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let mut vec: Vec<u8> = Vec::with_capacity(1000);
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unsafe {
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vec.set_len(0);
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}
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}
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