From 0e6f1631e47d8d0f9768a6668218db6743c6ef94 Mon Sep 17 00:00:00 2001
From: coastalwhite <me@gburghoorn.com>
Date: Thu, 23 Jan 2025 15:49:08 +0100
Subject: [PATCH] actually assign the schema

---
 crates/polars-mem-engine/src/executors/multi_file_scan.rs | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/crates/polars-mem-engine/src/executors/multi_file_scan.rs b/crates/polars-mem-engine/src/executors/multi_file_scan.rs
index 48eb7f81dfca..896927aaab89 100644
--- a/crates/polars-mem-engine/src/executors/multi_file_scan.rs
+++ b/crates/polars-mem-engine/src/executors/multi_file_scan.rs
@@ -266,10 +266,10 @@ impl MultiScanExec {
 
         let mut final_per_source_schema = Cow::Borrowed(self.file_info.schema.as_ref());
         if let Some(with_columns) = file_with_columns.as_ref() {
-            final_per_source_schema
-                .to_mut()
+            final_per_source_schema = Cow::Owned(final_per_source_schema
+                .as_ref()
                 .try_project(with_columns.as_ref())
-                .unwrap();
+                .unwrap());
         }
 
         // Remove the hive columns for each file load.