api: add resource claims to core API

The resource.k8s.io/ClaimTemplate only gets referenced by name, therefore the
changes to the core API are limited.

pkg/api/pod/util_test.go

@@ -784,6 +784,165 @@ func TestDropAppArmor(t *testing.T) {
 	}
 }
 
+func TestDropDynamicResourceAllocation(t *testing.T) {
+	resourceClaimName := "external-claim"
+
+	podWithClaims := &api.Pod{
+		Spec: api.PodSpec{
+			Containers: []api.Container{
+				{
+					Resources: api.ResourceRequirements{
+						Claims: []api.ResourceClaim{{Name: "my-claim"}},
+					},
+				},
+			},
+			InitContainers: []api.Container{
+				{
+					Resources: api.ResourceRequirements{
+						Claims: []api.ResourceClaim{{Name: "my-claim"}},
+					},
+				},
+			},
+			EphemeralContainers: []api.EphemeralContainer{
+				{
+					EphemeralContainerCommon: api.EphemeralContainerCommon{
+						Resources: api.ResourceRequirements{
+							Claims: []api.ResourceClaim{{Name: "my-claim"}},
+						},
+					},
+				},
+			},
+			ResourceClaims: []api.PodResourceClaim{
+				{
+					Name: "my-claim",
+					Source: api.ClaimSource{
+						ResourceClaimName: &resourceClaimName,
+					},
+				},
+			},
+		},
+	}
+	podWithoutClaims := &api.Pod{
+		Spec: api.PodSpec{
+			Containers:          []api.Container{{}},
+			InitContainers:      []api.Container{{}},
+			EphemeralContainers: []api.EphemeralContainer{{}},
+		},
+	}
+
+	var noPod *api.Pod
+
+	testcases := []struct {
+		description string
+		enabled     bool
+		oldPod      *api.Pod
+		newPod      *api.Pod
+		wantPod     *api.Pod
+	}{
+		{
+			description: "old with claims / new with claims / disabled",
+			oldPod:      podWithClaims,
+			newPod:      podWithClaims,
+			wantPod:     podWithClaims,
+		},
+		{
+			description: "old without claims / new with claims / disabled",
+			oldPod:      podWithoutClaims,
+			newPod:      podWithClaims,
+			wantPod:     podWithoutClaims,
+		},
+		{
+			description: "no old pod/ new with claims / disabled",
+			oldPod:      noPod,
+			newPod:      podWithClaims,
+			wantPod:     podWithoutClaims,
+		},
+
+		{
+			description: "old with claims / new without claims / disabled",
+			oldPod:      podWithClaims,
+			newPod:      podWithoutClaims,
+			wantPod:     podWithoutClaims,
+		},
+		{
+			description: "old without claims / new without claims / disabled",
+			oldPod:      podWithoutClaims,
+			newPod:      podWithoutClaims,
+			wantPod:     podWithoutClaims,
+		},
+		{
+			description: "no old pod/ new without claims / disabled",
+			oldPod:      noPod,
+			newPod:      podWithoutClaims,
+			wantPod:     podWithoutClaims,
+		},
+
+		{
+			description: "old with claims / new with claims / enabled",
+			enabled:     true,
+			oldPod:      podWithClaims,
+			newPod:      podWithClaims,
+			wantPod:     podWithClaims,
+		},
+		{
+			description: "old without claims / new with claims / enabled",
+			enabled:     true,
+			oldPod:      podWithoutClaims,
+			newPod:      podWithClaims,
+			wantPod:     podWithClaims,
+		},
+		{
+			description: "no old pod/ new with claims / enabled",
+			enabled:     true,
+			oldPod:      noPod,
+			newPod:      podWithClaims,
+			wantPod:     podWithClaims,
+		},
+
+		{
+			description: "old with claims / new without claims / enabled",
+			enabled:     true,
+			oldPod:      podWithClaims,
+			newPod:      podWithoutClaims,
+			wantPod:     podWithoutClaims,
+		},
+		{
+			description: "old without claims / new without claims / enabled",
+			enabled:     true,
+			oldPod:      podWithoutClaims,
+			newPod:      podWithoutClaims,
+			wantPod:     podWithoutClaims,
+		},
+		{
+			description: "no old pod/ new without claims / enabled",
+			enabled:     true,
+			oldPod:      noPod,
+			newPod:      podWithoutClaims,
+			wantPod:     podWithoutClaims,
+		},
+	}
+
+	for _, tc := range testcases {
+		t.Run(tc.description, func(t *testing.T) {
+			defer featuregatetesting.SetFeatureGateDuringTest(t, utilfeature.DefaultFeatureGate, features.DynamicResourceAllocation, tc.enabled)()
+
+			oldPod := tc.oldPod.DeepCopy()
+			newPod := tc.newPod.DeepCopy()
+			wantPod := tc.wantPod
+			DropDisabledPodFields(newPod, oldPod)
+
+			// old pod should never be changed
+			if diff := cmp.Diff(oldPod, tc.oldPod); diff != "" {
+				t.Errorf("old pod changed: %s", diff)
+			}
+
+			if diff := cmp.Diff(wantPod, newPod); diff != "" {
+				t.Errorf("new pod changed (- want, + got): %s", diff)
+			}
+		})
+	}
+}
+
 func TestDropProbeGracePeriod(t *testing.T) {
 	podWithProbeGracePeriod := func() *api.Pod {
 		livenessGracePeriod := int64(10)