Report current function name when invoke result length wrong (#13643)

This makes for a more actionable error message.

Author: findepi

datafusion/core/tests/user_defined/user_defined_scalar_functions.rs

@@ -251,7 +251,7 @@ async fn test_row_mismatch_error_in_scalar_udf() -> Result<()> {
             .err()
             .unwrap()
             .to_string(),
-        "UDF returned a different number of rows than expected"
+        "Internal error: UDF buggy_func returned a different number of rows than expected. Expected: 2, Got: 1"
     );
     Ok(())
 }

datafusion/physical-expr/src/scalar_function.rs

@@ -161,8 +161,8 @@ impl PhysicalExpr for ScalarFunctionExpr {
                 return if preserve_scalar {
                     ScalarValue::try_from_array(array, 0).map(ColumnarValue::Scalar)
                 } else {
-                    internal_err!("UDF returned a different number of rows than expected. Expected: {}, Got: {}",
-                            batch.num_rows(), array.len())
+                    internal_err!("UDF {} returned a different number of rows than expected. Expected: {}, Got: {}",
+                            self.name, batch.num_rows(), array.len())
                 };
             }
         }