From 57f3c96ba53b2f964dc571410a353c004caa3aaf Mon Sep 17 00:00:00 2001
From: Nick Lanham <nick.lanham@pm.me>
Date: Thu, 12 Sep 2024 16:14:54 -0700
Subject: [PATCH] only apply if needed

---
 kernel/src/engine/arrow_expression.rs | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/kernel/src/engine/arrow_expression.rs b/kernel/src/engine/arrow_expression.rs
index b42c2081..5995eb72 100644
--- a/kernel/src/engine/arrow_expression.rs
+++ b/kernel/src/engine/arrow_expression.rs
@@ -560,7 +560,10 @@ impl ExpressionEvaluator for DefaultExpressionEvaluator {
             let sa: &StructArray = array_ref
                 .as_struct_opt()
                 .ok_or(Error::unexpected_column_type("Expected a struct array"))?;
-            apply_schema(sa, &self.output_type)?
+            match ensure_data_types(&self.output_type, sa.data_type()) {
+                Ok(_) => sa.into(),
+                Err(_) => apply_schema(sa, &self.output_type)?
+            }
         } else {
             let schema = ArrowSchema::new(vec![ArrowField::new("output", arrow_type, true)]);
             RecordBatch::try_new(Arc::new(schema), vec![array_ref])?