[Variant] ReadOnlyMetadataBuilder borrows its underlying VariantMetadata #8502
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Which issue does this PR close?
Struct
#8336Rationale for this change
While pathfinding variant unshredding code, I noticed that there's a lot of variant metadata cloning going on. It's a 32-byte object, so cloning is not free. And it turns out that ~all read-only metadata builder usage in the code base can work just as easily with a borrowed reference because ultimately we're working with bytes borrowed from a binary view that holds the metadata column.
What changes are included in this PR?
Update the
ReadOnlyMetadataBuilder
to borrow theVariantMetadata
it uses, and update call sites accordingly.Are these changes tested?
Yes, the change affects several unit tests.
Are there any user-facing changes?
Signature of
ReadOnlyMetadataBuilder::new
has changed.