From 460b7be5bce8a8d27230b785e6bc9af5def285a2 Mon Sep 17 00:00:00 2001
From: Ying WANG <ying.wang@grafana.com>
Date: Tue, 24 Dec 2024 14:45:04 +0100
Subject: [PATCH] tsdb: Add MustIndex() function to Head

---
 tsdb/head_read.go      | 4 ++++
 tsdb/head_read_test.go | 3 +++
 2 files changed, 7 insertions(+)

diff --git a/tsdb/head_read.go b/tsdb/head_read.go
index a3cd7b653d..9ec0595dbd 100644
--- a/tsdb/head_read.go
+++ b/tsdb/head_read.go
@@ -37,6 +37,10 @@ func (h *Head) Index() (IndexReader, error) {
 	return h.indexRange(math.MinInt64, math.MaxInt64), nil
 }
 
+func (h *Head) MustIndex() IndexReader {
+	return h.indexRange(math.MinInt64, math.MaxInt64)
+}
+
 func (h *Head) indexRange(mint, maxt int64) *headIndexReader {
 	if hmin := h.MinTime(); hmin > mint {
 		mint = hmin
diff --git a/tsdb/head_read_test.go b/tsdb/head_read_test.go
index eb8487fde0..e59a73caf6 100644
--- a/tsdb/head_read_test.go
+++ b/tsdb/head_read_test.go
@@ -428,6 +428,9 @@ func TestHeadIndexReader_PostingsForLabelMatching(t *testing.T) {
 
 		ir, err := h.Index()
 		require.NoError(t, err)
+
+		irMust := h.MustIndex()
+		require.Equal(t, irMust, ir)
 		return ir
 	})
 }