Predicates on nested-leaf columns fail

[vvarma]

Apache Iceberg Rust version

0.6.0 (latest version)

Describe the bug

Nested-leaf predicates in the Arrow reader are rejected even when the predicate targets a primitive leaf inside a struct.
For example, a predicate like:

nested.value = 20

fails during row-filter construction because PredicateConverter::bound_reference resolves the predicate field ID to a Parquet leaf column, then rejects it when the Parquet column root is a group/struct.

To Reproduce

No response

Expected behavior

No response

Willingness to contribute

I can contribute a fix for this bug independently

[idan57570-art]

"I’ve analyzed the issue regarding nested-leaf predicates in the Arrow reader. While there is a PR linked (#2433), it's crucial that we ensure the PredicateConverter doesn't just resolve the field ID but also correctly handles the ProjectionMask for nested Parquet structures.

My proposed addition to the fix: We should implement a recursive check in bound_reference that validates the leaf type against the Arrow schema, even when the Parquet root is a group. This will prevent the row-filter from failing when it encounters struct-wrapped primitives.

I can assist in verifying the fix with additional unit tests for multi-level nested structs if needed.

Wallet: RTC972526299366 @Scottcjn"