chore: revert: drop deprecated allowSchedulingOnMasters

This reverts commit 32c67c2.

Signed-off-by: Noel Georgi <[email protected]>

hack/release.toml

@@ -23,13 +23,6 @@ preface = """
 
 Talos is built with Go 1.23.4.
 """
-    [notes.machineconfig]
-        title = "cluster.allowSchedulingOnMasters"
-        description = """\
-The machine config field item `.cluster.allowSchedulingOnMasters` which has been deprecated since Talos 1.2 has now been removed.
-Use the `.cluster.allowSchedulingOnControlPlanes` field instead.
-"""
-
     [notes.driver-rebind]
         title = "Driver Rebind"
         description = """\

pkg/machinery/config/generate/init.go

@@ -190,8 +190,13 @@ func (in *Input) init() ([]config.Document, error) {
 		ClusterInlineManifests: v1alpha1.ClusterInlineManifests{},
 	}
 
-	if in.Options.AllowSchedulingOnControlPlanes && in.Options.VersionContract.KubernetesAllowSchedulingOnControlPlanes() {
-		cluster.AllowSchedulingOnControlPlanes = pointer.To(in.Options.AllowSchedulingOnControlPlanes)
+	if in.Options.AllowSchedulingOnControlPlanes {
+		if in.Options.VersionContract.KubernetesAllowSchedulingOnControlPlanes() {
+			cluster.AllowSchedulingOnControlPlanes = pointer.To(in.Options.AllowSchedulingOnControlPlanes)
+		} else {
+			// backwards compatibility for Talos versions older than 1.2
+			cluster.AllowSchedulingOnMasters = pointer.To(in.Options.AllowSchedulingOnControlPlanes) //nolint:staticcheck
+		}
 	}
 
 	if in.Options.DiscoveryEnabled != nil {

pkg/machinery/config/types/v1alpha1/v1alpha1_clusterconfig.go

@@ -179,7 +179,11 @@ func (c *ClusterConfig) AdminKubeconfig() config.AdminKubeconfig {
 
 // ScheduleOnControlPlanes implements the config.ClusterConfig interface.
 func (c *ClusterConfig) ScheduleOnControlPlanes() bool {
-	return pointer.SafeDeref(c.AllowSchedulingOnControlPlanes)
+	if c.AllowSchedulingOnControlPlanes != nil {
+		return pointer.SafeDeref(c.AllowSchedulingOnControlPlanes)
+	}
+
+	return pointer.SafeDeref(c.AllowSchedulingOnMasters)
 }
 
 // ID returns the unique identifier for the cluster.

pkg/machinery/config/types/v1alpha1/v1alpha1_types.go

@@ -520,6 +520,10 @@ type ClusterConfig struct {
 	//   examples:
 	//     - value: clusterAdminKubeconfigExample()
 	AdminKubeconfigConfig *AdminKubeconfigConfig `yaml:"adminKubeconfig,omitempty"`
+	// docgen:nodoc
+	//
+	// Deprecated: Use `AllowSchedulingOnControlPlanes` instead.
+	AllowSchedulingOnMasters *bool `yaml:"allowSchedulingOnMasters,omitempty"`
 	//   description: |
 	//     Allows running workload on control-plane nodes.
 	//   values: