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author | Dylan DPC <dylan.dpc@gmail.com> | 2020-12-18 00:30:11 +0100 |
---|---|---|
committer | GitHub <noreply@github.com> | 2020-12-18 00:30:11 +0100 |
commit | 2e9ed6fb936f422bbb6be70468d8cd6b9b23495c (patch) | |
tree | 02127dabaa25feaf290eb339596615533312ce11 | |
parent | 720b6941dff18896bcab36bec8e905fdb462d7d8 (diff) | |
parent | 09d528ec155f77349001fa7eb6c3ae3363f41412 (diff) | |
download | rust-2e9ed6fb936f422bbb6be70468d8cd6b9b23495c.tar.gz |
Rollup merge of #80003 - Stupremee:fix-zst-vecdeque-conversion-panic, r=dtolnay
Fix overflow when converting ZST Vec to VecDeque
```rust
let v = vec![(); 100];
let queue = VecDeque::from(v);
println!("{:?}", queue);
```
This code will currently panic with a capacity overflow.
This PR resolves this issue and makes the code run fine.
Resolves #78532
-rw-r--r-- | library/alloc/src/collections/vec_deque/mod.rs | 8 | ||||
-rw-r--r-- | library/alloc/tests/vec_deque.rs | 7 |
2 files changed, 13 insertions, 2 deletions
diff --git a/library/alloc/src/collections/vec_deque/mod.rs b/library/alloc/src/collections/vec_deque/mod.rs index 57807bc5453..9e54c15ea6a 100644 --- a/library/alloc/src/collections/vec_deque/mod.rs +++ b/library/alloc/src/collections/vec_deque/mod.rs @@ -2793,8 +2793,12 @@ impl<T> From<Vec<T>> for VecDeque<T> { let len = other.len(); // We need to extend the buf if it's not a power of two, too small - // or doesn't have at least one free space - if !buf.capacity().is_power_of_two() + // or doesn't have at least one free space. + // We check if `T` is a ZST in the first condition, + // because `usize::MAX` (the capacity returned by `capacity()` for ZST) + // is not a power of two and thus it'll always try + // to reserve more memory which will panic for ZST (rust-lang/rust#78532) + if (!buf.capacity().is_power_of_two() && mem::size_of::<T>() != 0) || (buf.capacity() < (MINIMUM_CAPACITY + 1)) || (buf.capacity() == len) { diff --git a/library/alloc/tests/vec_deque.rs b/library/alloc/tests/vec_deque.rs index 705f0d62fbb..0919b1325bc 100644 --- a/library/alloc/tests/vec_deque.rs +++ b/library/alloc/tests/vec_deque.rs @@ -1728,3 +1728,10 @@ fn test_zero_sized_push() { } } } + +#[test] +fn test_from_zero_sized_vec() { + let v = vec![(); 100]; + let queue = VecDeque::from(v); + assert_eq!(queue.len(), 100); +} |