added various std traits for PyBackedStr and PyBackedBytes
#4020
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I was wondering about that as well. I'll try to come up with a few later. |
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I wonder, can we ship these in 0.21.1? Theoretically adding trait implementations can be breaking, but these types are so new and the traits so basic I can't really see them being a problem. I would definitely like to ship the Send / Sync implementations in 0.21.1. |
| @@ -79,13 +88,15 @@ impl FromPyObject<'_> for PyBackedStr { | |||
| /// A wrapper around `[u8]` where the storage is either owned by a Python `bytes` object, or a Rust `Box<[u8]>`. | |||
| /// | |||
| /// This type gives access to the underlying data via a `Deref` implementation. | |||
| #[derive(Clone)] | |||
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Isn't the derived Clone impl incorrect for the Rust variant? Cloning Box<[u8]> will yield a new allocation for data will still point to the old one meaning this is a use-after-free in waiting?
So we either need to manually fix up the data pointer or use a shared ownership pointer for the Rust side as well, e.g. Arc<[u8]>.
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(And so yes, these do need tests. ;-))
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Yes I was thinking similarly about the Box, an Arc seems reasonable to me.
I also half wonder if it was a mistake to have the Rust variant here given the name PyBackedBytes. I added it to support bytearrays in the same way we already do for Cow<[u8]> but on further reflection it does seem a bit add odds with the name that we do the copy.
I think probably it's ok as I would expect most uses to be with bytes, but we might want to document this copy-from-bytearray more clearly and justify for sake of safety.
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Isn't the derived
Cloneimpl incorrect for theRustvariant? CloningBox<[u8]>will yield a new allocation fordatawill still point to the old one meaning this is a use-after-free in waiting?
Big oops, thanks for catching.
Using Arc<[u8]> sounds good to me aswell, that way this stays a cheap clone either way.
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I've added the change to
I agree, since these types are so new, I think the chances of anyone relying on these impls not to be there are very low. Adding them in 0.21.1 should be fine I would say. |
Adds
Clone,Debug,PartialEq,Eq,PartialOrd,OrdandHashimplementation forPyBackedBytesandPyBackedStr, andDisplayforPyBackedStr. The implementations just delegate to&[u8]and&strrespectively.PartialEqandPartialOrdare also implemented betweenSelfandDeref::Targetrespectively.