From 606a815e0897fae89f3782a131ffe5888e2c3cba Mon Sep 17 00:00:00 2001
From: Frantisek Haifler <fh@convertingads.com>
Date: Tue, 6 Apr 2021 20:25:23 +0200
Subject: [PATCH] Enforce new allocation for appends on cloned joins slice

---
 exp/select_clauses.go      |  2 +-
 exp/select_clauses_test.go | 16 ++++++++++++++--
 2 files changed, 15 insertions(+), 3 deletions(-)

diff --git a/exp/select_clauses.go b/exp/select_clauses.go
index f5443caf..04cfc14b 100644
--- a/exp/select_clauses.go
+++ b/exp/select_clauses.go
@@ -112,7 +112,7 @@ func (c *selectClauses) clone() *selectClauses {
 		selectColumns: c.selectColumns,
 		distinct:      c.distinct,
 		from:          c.from,
-		joins:         c.joins,
+		joins:         c.joins[0:len(c.joins):len(c.joins)],
 		where:         c.where,
 		alias:         c.alias,
 		groupBy:       c.groupBy,
diff --git a/exp/select_clauses_test.go b/exp/select_clauses_test.go
index f5e0be1f..c0573959 100644
--- a/exp/select_clauses_test.go
+++ b/exp/select_clauses_test.go
@@ -160,21 +160,33 @@ func (scs *selectClausesSuite) TestJoins() {
 func (scs *selectClausesSuite) TestJoinsAppend() {
 	jc := NewConditionedJoinExpression(
 		LeftJoinType,
-		NewIdentifierExpression("", "test", ""),
+		NewIdentifierExpression("", "test1", ""),
 		nil,
 	)
 	jc2 := NewUnConditionedJoinExpression(
 		LeftJoinType,
-		NewIdentifierExpression("", "test", ""),
+		NewIdentifierExpression("", "test2", ""),
+	)
+	jc3 := NewUnConditionedJoinExpression(
+		InnerJoinType,
+		NewIdentifierExpression("", "test3", ""),
 	)
 	c := NewSelectClauses()
 	c2 := c.JoinsAppend(jc)
 	c3 := c2.JoinsAppend(jc2)
 
+	c4 := c3.JoinsAppend(jc2) // len(c4.joins) == 3, cap(c4.joins) == 4
+	// next two appends shouldn't affect one another
+	c5 := c4.JoinsAppend(jc2)
+	c6 := c4.JoinsAppend(jc3)
+
 	scs.Nil(c.Joins())
 
 	scs.Equal(JoinExpressions{jc}, c2.Joins())
 	scs.Equal(JoinExpressions{jc, jc2}, c3.Joins())
+	scs.Equal(JoinExpressions{jc, jc2, jc2}, c4.Joins())
+	scs.Equal(JoinExpressions{jc, jc2, jc2, jc2}, c5.Joins())
+	scs.Equal(JoinExpressions{jc, jc2, jc2, jc3}, c6.Joins())
 }
 
 func (scs *selectClausesSuite) TestWhere() {