Enforce uniqueness of named_struct field names (#11614)

* check struct field names for uniqueness

* add logic test

* improve error log

Author: dharanad

datafusion/functions/src/core/named_struct.rs

@@ -20,6 +20,7 @@ use arrow::datatypes::{DataType, Field, Fields};
 use datafusion_common::{exec_err, internal_err, Result, ScalarValue};
 use datafusion_expr::{ColumnarValue, Expr, ExprSchemable};
 use datafusion_expr::{ScalarUDFImpl, Signature, Volatility};
+use hashbrown::HashSet;
 use std::any::Any;
 use std::sync::Arc;
 
@@ -45,7 +46,6 @@ fn named_struct_expr(args: &[ColumnarValue]) -> Result<ColumnarValue> {
         .map(|(i, chunk)| {
 
             let name_column = &chunk[0];
-
             let name = match name_column {
                 ColumnarValue::Scalar(ScalarValue::Utf8(Some(name_scalar))) => name_scalar,
                 _ => return exec_err!("named_struct even arguments must be string literals, got {name_column:?} instead at position {}", i * 2)
@@ -57,6 +57,19 @@ fn named_struct_expr(args: &[ColumnarValue]) -> Result<ColumnarValue> {
         .into_iter()
         .unzip();
 
+    {
+        // Check to enforce the uniqueness of struct field name
+        let mut unique_field_names = HashSet::new();
+        for name in names.iter() {
+            if unique_field_names.contains(name) {
+                return exec_err!(
+                    "named_struct requires unique field names. Field {name} is used more than once."
+                );
+            }
+            unique_field_names.insert(name);
+        }
+    }
+
     let arrays = ColumnarValue::values_to_arrays(&values)?;
 
     let fields = names

datafusion/sqllogictest/test_files/struct.slt

@@ -122,6 +122,10 @@ physical_plan
 query error
 select named_struct();
 
+# error on duplicate field names
+query error
+select named_struct('c0': 1, 'c1': 2, 'c1': 3);
+
 # error on odd number of arguments #1
 query error DataFusion error: Execution error: named_struct requires an even number of arguments, got 1 instead
 select named_struct('a');