Add apache#17285 reproducer case

Author: kosiew

datafusion-examples/examples/struct_cast_reorder.rs

@@ -0,0 +1,97 @@
+use arrow::array::{Int64Array, RecordBatch, StructArray};
+use arrow::datatypes::{DataType, Field, Fields, Schema};
+use datafusion::execution::context::SessionContext;
+use datafusion::logical_expr::{cast, col};
+use std::sync::Arc;
+
+#[tokio::main]
+async fn main() -> Result<(), Box<dyn std::error::Error>> {
+    let ctx = SessionContext::new();
+
+    // Source: struct with fields [b=3, a=4]
+    let source_fields = Fields::from(vec![
+        Field::new("b", DataType::Int64, false),
+        Field::new("a", DataType::Int64, false),
+    ]);
+
+    let source_struct = StructArray::new(
+        source_fields.clone(),
+        vec![
+            Arc::new(Int64Array::from(vec![3i64])), // b = 3
+            Arc::new(Int64Array::from(vec![4i64])), // a = 4
+        ],
+        None,
+    );
+
+    let batch = RecordBatch::try_new(
+        Arc::new(Schema::new(vec![Field::new(
+            "s",
+            DataType::Struct(source_fields),
+            false,
+        )])),
+        vec![Arc::new(source_struct)],
+    )?;
+
+    let table = datafusion::datasource::memory::MemTable::try_new(
+        batch.schema(),
+        vec![vec![batch]],
+    )?;
+
+    ctx.register_table("t", Arc::new(table))?;
+
+    // Validate source data: should be b=3, a=4
+    let source_data = ctx.table("t").await?.collect().await?;
+    use arrow::array::AsArray;
+    let src_struct = source_data[0].column(0).as_struct();
+    let src_a = src_struct
+        .column_by_name("a")
+        .unwrap()
+        .as_primitive::<arrow::array::types::Int64Type>()
+        .value(0);
+    let src_b = src_struct
+        .column_by_name("b")
+        .unwrap()
+        .as_primitive::<arrow::array::types::Int64Type>()
+        .value(0);
+    assert_eq!(src_a, 4, "Source field 'a' should be 4");
+    assert_eq!(src_b, 3, "Source field 'b' should be 3");
+    println!("✓ Source validation passed: b={}, a={}", src_b, src_a);
+
+    // Target: reorder fields to [a, b]
+    let target_type = DataType::Struct(Fields::from(vec![
+        Field::new("a", DataType::Int64, false),
+        Field::new("b", DataType::Int64, false),
+    ]));
+
+    // Execute cast
+    let result = ctx
+        .table("t")
+        .await?
+        .select(vec![cast(col("s"), target_type)])?
+        .collect()
+        .await?;
+
+    // Validate result
+    let res_struct = result[0].column(0).as_struct();
+    let res_a = res_struct
+        .column_by_name("a")
+        .unwrap()
+        .as_primitive::<arrow::array::types::Int64Type>()
+        .value(0);
+    let res_b = res_struct
+        .column_by_name("b")
+        .unwrap()
+        .as_primitive::<arrow::array::types::Int64Type>()
+        .value(0);
+
+    if res_a == 4 && res_b == 3 {
+        println!("✓ Cast result passed: a={}, b={}", res_a, res_b);
+    } else {
+        println!(
+            "✗ Bug: Cast maps by position, not name. Expected a=4,b=3 but got a={}, b={}",
+            res_a, res_b
+        );
+    }
+
+    Ok(())
+}