From 47fba23f9cac9ff1884e35967cdcece5bab171f7 Mon Sep 17 00:00:00 2001
From: Andrew Lamb <andrew@nerdnetworks.org>
Date: Mon, 24 Jun 2024 18:39:18 -0400
Subject: [PATCH] Deprecate Expr::column_refs

---
 datafusion/expr/src/expr.rs                 | 1 +
 datafusion/expr/src/logical_plan/builder.rs | 9 ++++++---
 2 files changed, 7 insertions(+), 3 deletions(-)

diff --git a/datafusion/expr/src/expr.rs b/datafusion/expr/src/expr.rs
index 551f61ed5aad..7f4301f135f0 100644
--- a/datafusion/expr/src/expr.rs
+++ b/datafusion/expr/src/expr.rs
@@ -1329,6 +1329,7 @@ impl Expr {
     }
 
     /// Return all referenced columns of this expression.
+    #[deprecated(since = "40.0.0", note = "use Expr::column_refs instead")]
     pub fn to_columns(&self) -> Result<HashSet<Column>> {
         let mut using_columns = HashSet::new();
         expr_to_columns(self, &mut using_columns)?;
diff --git a/datafusion/expr/src/logical_plan/builder.rs b/datafusion/expr/src/logical_plan/builder.rs
index 434f4dace1de..4564a8c71fcd 100644
--- a/datafusion/expr/src/logical_plan/builder.rs
+++ b/datafusion/expr/src/logical_plan/builder.rs
@@ -39,7 +39,8 @@ use crate::logical_plan::{
 use crate::type_coercion::binary::{comparison_coercion, values_coercion};
 use crate::utils::{
     can_hash, columnize_expr, compare_sort_expr, expand_qualified_wildcard,
-    expand_wildcard, find_valid_equijoin_key_pair, group_window_expr_by_sort_keys,
+    expand_wildcard, expr_to_columns, find_valid_equijoin_key_pair,
+    group_window_expr_by_sort_keys,
 };
 use crate::{
     and, binary_expr, logical_plan::tree_node::unwrap_arc, DmlStatement, Expr,
@@ -1070,14 +1071,16 @@ impl LogicalPlanBuilder {
                 let left_key = l.into();
                 let right_key = r.into();
 
-                let left_using_columns = left_key.to_columns()?;
+                let mut left_using_columns = HashSet::new();
+                expr_to_columns(&left_key, &mut left_using_columns)?;
                 let normalized_left_key = normalize_col_with_schemas_and_ambiguity_check(
                     left_key,
                     &[&[self.plan.schema(), right.schema()]],
                     &[left_using_columns],
                 )?;
 
-                let right_using_columns = right_key.to_columns()?;
+                let mut right_using_columns = HashSet::new();
+                expr_to_columns(&right_key, &mut right_using_columns)?;
                 let normalized_right_key = normalize_col_with_schemas_and_ambiguity_check(
                     right_key,
                     &[&[self.plan.schema(), right.schema()]],