fix: fix isFallbackEnabled when using scaling modifiers (#6521)

Signed-off-by: Youssef Rabie <[email protected]>
Co-authored-by: Zbynek Roubalik <[email protected]>

CHANGELOG.md

@@ -56,6 +56,7 @@ To learn more about active deprecations, we recommend checking [GitHub Discussio
 - [v1.0.0](#v100)
 
 ## Unreleased
+- **General**: Fix the check whether Fallback is enabled when using ScalingModifiers ([#6521](https://github.com/kedacore/keda/pull/6521))
 
 - **General**: Introduce new Temporal scaler ([#4724](https://github.com/kedacore/keda/issues/4724))
 

pkg/fallback/fallback.go

@@ -38,7 +38,12 @@ func isFallbackEnabled(scaledObject *kedav1alpha1.ScaledObject, metricSpec v2.Me
 		return false
 	}
 
-	if metricSpec.External.Target.Type != v2.AverageValueMetricType {
+	// If we are using ScalingModifiers, we only care whether its metric type is AverageValue.
+	// If not, test the type of metricSpec passed.
+	if scaledObject.IsUsingModifiers() && scaledObject.Spec.Advanced.ScalingModifiers.MetricType != v2.AverageValueMetricType {
+		log.V(0).Info("Fallback can only be enabled for scalingModifiers with metric of type AverageValue", "scaledObject.Namespace", scaledObject.Namespace, "scaledObject.Name", scaledObject.Name)
+		return false
+	} else if !scaledObject.IsUsingModifiers() && metricSpec.External.Target.Type != v2.AverageValueMetricType {
 		log.V(0).Info("Fallback can only be enabled for triggers with metric of type AverageValue", "scaledObject.Namespace", scaledObject.Namespace, "scaledObject.Name", scaledObject.Name)
 		return false
 	}