From 64de6ddd6c7d776aa94bf3464e912383274048c3 Mon Sep 17 00:00:00 2001
From: Peter Toth <peter.toth@gmail.com>
Date: Sat, 25 May 2024 15:01:18 +0200
Subject: [PATCH] Minor: Use slice in `ConcreteTreeNode`

---
 datafusion/common/src/tree_node.rs               | 4 ++--
 datafusion/physical-expr-common/src/tree_node.rs | 4 ++--
 datafusion/physical-plan/src/tree_node.rs        | 4 ++--
 3 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/datafusion/common/src/tree_node.rs b/datafusion/common/src/tree_node.rs
index 9d42f4fb1e0d..f0e889e7cf74 100644
--- a/datafusion/common/src/tree_node.rs
+++ b/datafusion/common/src/tree_node.rs
@@ -903,7 +903,7 @@ impl<T: DynTreeNode + ?Sized> TreeNode for Arc<T> {
 /// involving payloads, by enforcing rules for detaching and reattaching child nodes.
 pub trait ConcreteTreeNode: Sized {
     /// Provides read-only access to child nodes.
-    fn children(&self) -> Vec<&Self>;
+    fn children(&self) -> &[Self];
 
     /// Detaches the node from its children, returning the node itself and its detached children.
     fn take_children(self) -> (Self, Vec<Self>);
@@ -917,7 +917,7 @@ impl<T: ConcreteTreeNode> TreeNode for T {
         &self,
         f: F,
     ) -> Result<TreeNodeRecursion> {
-        self.children().into_iter().apply_until_stop(f)
+        self.children().iter().apply_until_stop(f)
     }
 
     fn map_children<F: FnMut(Self) -> Result<Transformed<Self>>>(
diff --git a/datafusion/physical-expr-common/src/tree_node.rs b/datafusion/physical-expr-common/src/tree_node.rs
index 42dc6673af6a..5de6457b8e5e 100644
--- a/datafusion/physical-expr-common/src/tree_node.rs
+++ b/datafusion/physical-expr-common/src/tree_node.rs
@@ -84,8 +84,8 @@ impl<T: Display> Display for ExprContext<T> {
 }
 
 impl<T> ConcreteTreeNode for ExprContext<T> {
-    fn children(&self) -> Vec<&Self> {
-        self.children.iter().collect()
+    fn children(&self) -> &[Self] {
+        &self.children
     }
 
     fn take_children(mut self) -> (Self, Vec<Self>) {
diff --git a/datafusion/physical-plan/src/tree_node.rs b/datafusion/physical-plan/src/tree_node.rs
index 46460cbb6684..d3b51062c25c 100644
--- a/datafusion/physical-plan/src/tree_node.rs
+++ b/datafusion/physical-plan/src/tree_node.rs
@@ -86,8 +86,8 @@ impl<T: Display> Display for PlanContext<T> {
 }
 
 impl<T> ConcreteTreeNode for PlanContext<T> {
-    fn children(&self) -> Vec<&Self> {
-        self.children.iter().collect()
+    fn children(&self) -> &[Self] {
+        &self.children
     }
 
     fn take_children(mut self) -> (Self, Vec<Self>) {