app/vmselect/promql: do not crash if histogram_over_time() function name contains uppercase letters such as Histogram_over_time()

app/vmselect/promql/exec_test.go

@@ -4525,6 +4525,17 @@ func TestExecSuccess(t *testing.T) {
 		resultExpected := []netstorage.Result{r}
 		f(q, resultExpected)
 	})
+	t.Run(`sum(Histogram_OVER_time)`, func(t *testing.T) {
+		t.Parallel()
+		q := `sum(Histogram_OVER_time(alias(label_set(rand(0)*1.3+1.1, "foo", "bar"), "xxx")[200s:5s]))`
+		r := netstorage.Result{
+			MetricName: metricNameExpected,
+			Values:     []float64{40, 40, 40, 40, 40, 40},
+			Timestamps: timestampsExpected,
+		}
+		resultExpected := []netstorage.Result{r}
+		f(q, resultExpected)
+	})
 	t.Run(`topk_max(histogram_over_time)`, func(t *testing.T) {
 		t.Parallel()
 		q := `topk_max(1, histogram_over_time(alias(label_set(rand(0)*1.3+1.1, "foo", "bar"), "xxx")[200s:5s]))`

app/vmselect/promql/rollup.go

@@ -426,7 +426,7 @@ type timeseriesMap struct {
 }
 
 func newTimeseriesMap(funcName string, sharedTimestamps []int64, mnSrc *storage.MetricName) *timeseriesMap {
-	if funcName != "histogram_over_time" {
+	if strings.ToLower(funcName) != "histogram_over_time" {
 		return nil
 	}
 

docs/CHANGELOG.md

@@ -24,6 +24,7 @@
 * BUGFUX: avoid `duplicate time series` error if `prometheus_buckets()` covers a time range with distinct set of buckets.
 * BUGFIX: prevent exponent overflow when processing extremely small values close to zero such as `2.964393875E-314`. See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/1114
 * BUGFIX: do not include datapoints with a timestamp `t-d` when returning results from `/api/v1/query?query=m[d]&time=t` as Prometheus does.
+* BUGFIX: do not crash if a query contains `histogram_over_time()` function name with uppercase chars. For example, `Histogram_Over_Time(m[5m])`.
 
 
 # [v1.55.1](https://github.com/VictoriaMetrics/VictoriaMetrics/releases/tag/v1.55.1)