fix clippy

Author: FANNG1

crates/iceberg/src/expr/predicate.rs

@@ -132,7 +132,16 @@ impl<T: Bind> Bind for UnaryExpression<T> {
 }
 
 impl<T> UnaryExpression<T> {
-    /// Create a unary expression
+    /// Creates a unary expression with the given operator and term.
+    ///
+    ///
+    /// # Example
+    ///
+    /// ```rust
+    /// use iceberg::expr::{PredicateOperator, Reference, UnaryExpression};
+    ///
+    /// UnaryExpression::new(PredicateOperator::IsNull, Reference::new("c"));
+    /// ```
     pub fn new(op: PredicateOperator, term: T) -> Self {
         debug_assert!(op.is_unary());
         Self { op, term }
@@ -172,7 +181,17 @@ impl<T: Debug> Debug for BinaryExpression<T> {
 }
 
 impl<T> BinaryExpression<T> {
-    /// Create a new BinaryExpression
+    /// Creates a binary expression with the given operator and term.
+    ///
+    /// # Example
+    ///
+    /// ```rust
+    /// use iceberg::expr::Datum;
+    /// use iceberg::expr::PredicateOperator;
+    /// use iceberg::expr::Reference;
+    ///
+    /// BinaryExpression::new(PredicateOperator::LessThanOrEq, Reference::new("a"), Datum::int(10);
+    /// ```
     pub fn new(op: PredicateOperator, term: T, literal: Datum) -> Self {
         debug_assert!(op.is_binary());
         Self { op, term, literal }

crates/integrations/datafusion/src/physical_plan/expr_to_predicate.rs

@@ -22,7 +22,7 @@ use datafusion::scalar::ScalarValue;
 use iceberg::expr::{BinaryExpression, Predicate, PredicateOperator, Reference, UnaryExpression};
 use iceberg::spec::Datum;
 
-// A datafusion expression could be an Iceberg predicate, reference, or dataum.
+// A datafusion expression could be an Iceberg predicate, column, or literal.
 enum TransformedResult {
     Predication(Predicate),
     Column(Reference),

crates/integrations/datafusion/src/table.rs

@@ -23,7 +23,7 @@ use datafusion::arrow::datatypes::SchemaRef as ArrowSchemaRef;
 use datafusion::catalog::Session;
 use datafusion::datasource::{TableProvider, TableType};
 use datafusion::error::Result as DFResult;
-use datafusion::logical_expr::{BinaryExpr, Expr, TableProviderFilterPushDown};
+use datafusion::logical_expr::{Expr, TableProviderFilterPushDown};
 use datafusion::physical_plan::ExecutionPlan;
 use iceberg::arrow::schema_to_arrow_schema;
 use iceberg::table::Table;
@@ -92,14 +92,7 @@ impl TableProvider for IcebergTableProvider {
         filters: &[&Expr],
     ) -> std::result::Result<Vec<TableProviderFilterPushDown>, datafusion::error::DataFusionError>
     {
-        let filter_support = filters
-            .iter()
-            .map(|e| match e {
-                Expr::BinaryExpr(BinaryExpr { .. }) => TableProviderFilterPushDown::Inexact,
-                _ => TableProviderFilterPushDown::Unsupported,
-            })
-            .collect::<Vec<TableProviderFilterPushDown>>();
-
-        Ok(filter_support)
+        // Push down all filters, as a single source of truth, the scanner will drop the filters which couldn't be push down
+        Ok(vec![TableProviderFilterPushDown::Inexact; filters.len()])
     }
 }