Fix panic where model.NameValidationScheme isn't set

Signed-off-by: Arthur Silva Sens <[email protected]>

receiver/prometheusreceiver/factory.go

@@ -6,6 +6,7 @@ package prometheusreceiver // import "github.com/open-telemetry/opentelemetry-co
 import (
 	"context"
 
+	"github.com/prometheus/common/model"
 	promconfig "github.com/prometheus/prometheus/config"
 	_ "github.com/prometheus/prometheus/discovery/install" // init() of this package registers service discovery impl.
 	"go.opentelemetry.io/collector/component"
@@ -35,6 +36,12 @@ var enableNativeHistogramsGate = featuregate.GlobalRegistry().MustRegister(
 
 // NewFactory creates a new Prometheus receiver factory.
 func NewFactory() receiver.Factory {
+	// Since Prometheus 3.0, the default validation scheme for metric names is UTF8.
+	// This includes ScrapeManager lib that is used by the Promethes receiver.
+	// We need to set the validation scheme to _something_ to avoid panics, and
+	// UTF8 is the default in Prometheus.
+	model.NameValidationScheme = model.UTF8Validation
+
 	return receiver.NewFactory(
 		metadata.Type,
 		createDefaultConfig,