From e4b579fa9062f24b00d915dd972f1d8f1ea415f6 Mon Sep 17 00:00:00 2001
From: Ben Ye <benye@amazon.com>
Date: Tue, 17 Oct 2023 20:33:54 -0700
Subject: [PATCH] Fix matchersToPostingGroups vals variable shadow bug (#6817)

* fix matchersToPostingGroups vals variable shadow bug

Signed-off-by: Ben Ye <benye@amazon.com>

* update changelog

Signed-off-by: Ben Ye <benye@amazon.com>

---------

Signed-off-by: Ben Ye <benye@amazon.com>
---
 CHANGELOG.md             |  1 +
 pkg/store/bucket.go      |  3 ++-
 pkg/store/bucket_test.go | 23 +++++++++++++++++++++++
 3 files changed, 26 insertions(+), 1 deletion(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 7ba214b606..eb6e8569c3 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -13,6 +13,7 @@ We use *breaking :warning:* to mark changes that are not backward compatible (re
 ### Fixed
 
 - [#6802](https://github.com/thanos-io/thanos/pull/6802) Receive: head series limiter should not run if no head series limit is set.
+- [#6817](https://github.com/thanos-io/thanos/pull/6817) Store Gateway: fix `matchersToPostingGroups` label values variable got shadowed bug.
 
 ### Added
 
diff --git a/pkg/store/bucket.go b/pkg/store/bucket.go
index 006a4b0ded..7b9676e915 100644
--- a/pkg/store/bucket.go
+++ b/pkg/store/bucket.go
@@ -2664,8 +2664,9 @@ func matchersToPostingGroups(ctx context.Context, lvalsFn func(name string) ([]s
 			}
 			// Cache label values because label name is the same.
 			if !valuesCached && vals != nil {
+				lvals := vals
 				lvalsFunc = func(_ string) ([]string, error) {
-					return vals, nil
+					return lvals, nil
 				}
 				valuesCached = true
 			}
diff --git a/pkg/store/bucket_test.go b/pkg/store/bucket_test.go
index 4dc3c59643..6e2949ac02 100644
--- a/pkg/store/bucket_test.go
+++ b/pkg/store/bucket_test.go
@@ -3132,6 +3132,29 @@ func TestMatchersToPostingGroup(t *testing.T) {
 				},
 			},
 		},
+		{
+			name: "Reproduce values shadow bug",
+			matchers: []*labels.Matcher{
+				labels.MustNewMatcher(labels.MatchRegexp, "name", "test.*"),
+				labels.MustNewMatcher(labels.MatchNotRegexp, "name", "testfoo"),
+				labels.MustNewMatcher(labels.MatchNotEqual, "name", ""),
+			},
+			labelValues: map[string][]string{
+				"name": {"testbar", "testfoo"},
+			},
+			expected: []*postingGroup{
+				{
+					name:    "name",
+					addAll:  false,
+					addKeys: []string{"testbar"},
+					matchers: []*labels.Matcher{
+						labels.MustNewMatcher(labels.MatchNotEqual, "name", ""),
+						labels.MustNewMatcher(labels.MatchRegexp, "name", "test.*"),
+						labels.MustNewMatcher(labels.MatchNotRegexp, "name", "testfoo"),
+					},
+				},
+			},
+		},
 	} {
 		t.Run(tc.name, func(t *testing.T) {
 			actual, err := matchersToPostingGroups(ctx, func(name string) ([]string, error) {