RUST-2471 Fix Eq implementation for Bson; extend Eq/Hash to raw types - #686
RUST-2471 Fix Eq implementation for Bson; extend Eq/Hash to raw types#686abr-egn wants to merge 1 commit into
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| impl std::hash::Hash for RawBson { | ||
| fn hash<H: std::hash::Hasher>(&self, state: &mut H) { | ||
| std::mem::discriminant(self).hash(state); |
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This is unrelated to the rest of the changes, but since we're changing the hash output (or adding it in the case of the raw types), this makes it behave a little better. Including the discriminant in the hash reduces collisions; previously, all the unit variants would hash equal, as would pairs like Bson::String("x") and Bson::Symbol("x").
| impl<'a> PartialEq for RawBsonRef<'a> { | ||
| fn eq(&self, other: &Self) -> bool { | ||
| match self { | ||
| Self::Double(s) => matches!(other, Self::Double(o) if s.to_bits() == o.to_bits()), |
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This slightly awkward construction means there doesn't need to be a fallthrough case like there would be for matching directly against (self, other), so we keep the compile-time exhaustiveness check.
| std::mem::discriminant(self).hash(state); | ||
| match self { | ||
| Bson::Double(double) => { | ||
| if *double == 0.0_f64 { |
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This special casing goes away because both equality and hash are just using the byte values.
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RUST-2471
This changes the
Bsonimpl forPartialEqto compare by byte value rather than the derived comparison, which carried the float non-reflexive behavior and madeEqa lie. To keep things consistent, I updated the raw types to use the same comparison; this also meant making the raw types Eq/Hash was straightforward.Notably, the raw buffer types (
RawDocument[Buf],RawArray[Buf]) were already just comparing by byte value, so this change makes everything consistent rather than having an undocumented mismatch.Fixes #683, #684.