From 8ee0d62d9ee8c8c16a30fbe5eb43e0e619a0ac15 Mon Sep 17 00:00:00 2001
From: Cyril Tovena <cyril.tovena@gmail.com>
Date: Mon, 20 Jun 2022 09:50:29 +0200
Subject: [PATCH] Fixes bad initialization for uniqueString (#6432)

---
 pkg/logql/log/util.go      |  2 +-
 pkg/logql/log/util_test.go | 13 ++++++++++++-
 2 files changed, 13 insertions(+), 2 deletions(-)

diff --git a/pkg/logql/log/util.go b/pkg/logql/log/util.go
index eb7eb33120aa3..8db9083b4fa53 100644
--- a/pkg/logql/log/util.go
+++ b/pkg/logql/log/util.go
@@ -6,7 +6,7 @@ import (
 
 func uniqueString(s []string) []string {
 	unique := make(map[string]bool, len(s))
-	us := make([]string, len(unique))
+	us := make([]string, 0, len(s))
 	for _, elem := range s {
 		if len(elem) != 0 {
 			if !unique[elem] {
diff --git a/pkg/logql/log/util_test.go b/pkg/logql/log/util_test.go
index beb9e2d3ae0e3..f71eeb6f4c18f 100644
--- a/pkg/logql/log/util_test.go
+++ b/pkg/logql/log/util_test.go
@@ -1,6 +1,10 @@
 package log
 
-import "testing"
+import (
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
 
 func Test_sanitizeLabelKey(t *testing.T) {
 	tests := []struct {
@@ -23,3 +27,10 @@ func Test_sanitizeLabelKey(t *testing.T) {
 		})
 	}
 }
+
+func Test_UniqueStrings(t *testing.T) {
+	in := []string{"foo", "bar", "baz", "foo"}
+	out := uniqueString(in)
+	require.Equal(t, []string{"foo", "bar", "baz"}, out)
+	require.Equal(t, 4, cap(out))
+}