fix: restore WAL from replica source during designated primary promotion

internal/cnpgi/common/wal.go

@@ -224,7 +224,6 @@ func (w WALServiceImplementation) Archive(
 }
 
 // Restore implements the WALService interface
-// nolint: gocognit
 func (w WALServiceImplementation) Restore(
 	ctx context.Context,
 	request *wal.WALRestoreRequest,
@@ -239,36 +238,7 @@ func (w WALServiceImplementation) Restore(
 		return nil, err
 	}
 
-	var serverName string
-	var objectStoreKey types.NamespacedName
-
-	var promotionToken string
-	if configuration.Cluster.Spec.ReplicaCluster != nil {
-		promotionToken = configuration.Cluster.Spec.ReplicaCluster.PromotionToken
-	}
-
-	switch {
-	case promotionToken != "" && configuration.Cluster.Status.LastPromotionToken != promotionToken:
-		// This is a replica cluster that is being promoted to a primary cluster
-		// Recover from the replica source object store
-		serverName = configuration.ReplicaSourceServerName
-		objectStoreKey = configuration.GetReplicaSourceBarmanObjectKey()
-
-	case configuration.Cluster.IsReplica() && configuration.Cluster.Status.CurrentPrimary == w.InstanceName:
-		// Designated primary on replica cluster, using replica source object store
-		serverName = configuration.ReplicaSourceServerName
-		objectStoreKey = configuration.GetReplicaSourceBarmanObjectKey()
-
-	case configuration.Cluster.Status.CurrentPrimary == "":
-		// Recovery from object store, using recovery object store
-		serverName = configuration.RecoveryServerName
-		objectStoreKey = configuration.GetRecoveryBarmanObjectKey()
-
-	default:
-		// Using cluster object store
-		serverName = configuration.ServerName
-		objectStoreKey = configuration.GetBarmanObjectKey()
-	}
+	serverName, objectStoreKey := resolveRestoreObjectStore(configuration, w.InstanceName)
 
 	var objectStore barmancloudv1.ObjectStore
 	if err := w.Client.Get(ctx, objectStoreKey, &objectStore); err != nil {
@@ -284,6 +254,33 @@ func (w WALServiceImplementation) Restore(
 		ctx, configuration.Cluster, &objectStore, serverName, walName, destinationPath)
 }
 
+// resolveRestoreObjectStore selects the object store and server name to use when
+// restoring a WAL file, based on the role this instance plays in the cluster.
+func resolveRestoreObjectStore(
+	configuration *config.PluginConfiguration,
+	instanceName string,
+) (serverName string, objectStoreKey types.NamespacedName) {
+	switch {
+	case configuration.Cluster.Status.CurrentPrimary == instanceName &&
+		len(configuration.ReplicaSourceBarmanObjectName) > 0:
+		// PostgreSQL never runs restore_command on a live primary; it runs only while
+		// the instance is in recovery (a genuine standby, restoring from a backup, or
+		// being rewound by pg_rewind). So a current primary that still has a replica
+		// source configured can only be a designated primary that has not finished
+		// promoting, and it must keep fetching WAL from the replica source.
+		// Token-agnostic: covers both switchover and failover.
+		return configuration.ReplicaSourceServerName, configuration.GetReplicaSourceBarmanObjectKey()
+
+	case configuration.Cluster.Status.CurrentPrimary == "":
+		// Recovery from object store, using recovery object store
+		return configuration.RecoveryServerName, configuration.GetRecoveryBarmanObjectKey()
+
+	default:
+		// Using cluster object store
+		return configuration.ServerName, configuration.GetBarmanObjectKey()
+	}
+}
+
 func (w WALServiceImplementation) restoreFromBarmanObjectStore(
 	ctx context.Context,
 	cluster *cnpgv1.Cluster,

internal/cnpgi/common/wal_test.go

@@ -0,0 +1,98 @@
+/*
+Copyright © contributors to CloudNativePG, established as
+CloudNativePG a Series of LF Projects, LLC.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+
+SPDX-License-Identifier: Apache-2.0
+*/
+
+package common
+
+import (
+	cnpgv1 "github.com/cloudnative-pg/cloudnative-pg/api/v1"
+	. "github.com/onsi/ginkgo/v2"
+	. "github.com/onsi/gomega"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+
+	"github.com/cloudnative-pg/plugin-barman-cloud/internal/cnpgi/operator/config"
+)
+
+var _ = Describe("resolveRestoreObjectStore", func() {
+	const (
+		namespace = "test-ns"
+		instance  = "cluster-1"
+	)
+
+	// newConfig builds a PluginConfiguration with distinct, recognizable names
+	// for every candidate object store, so each test can assert exactly which
+	// one the routing selected.
+	newConfig := func(currentPrimary, replicaSourceObject string) *config.PluginConfiguration {
+		return &config.PluginConfiguration{
+			Cluster: &cnpgv1.Cluster{
+				ObjectMeta: metav1.ObjectMeta{Namespace: namespace},
+				Status:     cnpgv1.ClusterStatus{CurrentPrimary: currentPrimary},
+			},
+			BarmanObjectName:              "cluster-store",
+			ServerName:                    "cluster-server",
+			RecoveryBarmanObjectName:      "recovery-store",
+			RecoveryServerName:            "recovery-server",
+			ReplicaSourceBarmanObjectName: replicaSourceObject,
+			ReplicaSourceServerName:       "replica-server",
+		}
+	}
+
+	DescribeTable(
+		"selects the correct object store for restoring WAL files",
+		func(cfg *config.PluginConfiguration, wantServer, wantObject string) {
+			gotServer, gotKey := resolveRestoreObjectStore(cfg, instance)
+
+			Expect(gotServer).To(Equal(wantServer))
+			Expect(gotKey.Name).To(Equal(wantObject))
+			Expect(gotKey.Namespace).To(Equal(namespace))
+		},
+
+		// The regression this guards: during a designated-primary promotion the
+		// instance is already the current primary while still in recovery, and it
+		// must pull remaining WALs from the replica source. The routing decision does
+		// not depend on the promotion token, so this single case covers both
+		// switchover and failover.
+		Entry("designated primary in promotion -> replica source",
+			newConfig(instance, "replica-store"),
+			"replica-server", "replica-store"),
+
+		// Guards the len(ReplicaSourceBarmanObjectName) > 0 gate: a current primary
+		// without a barman-backed replica source (plain HA primary, or a replica
+		// cluster whose source is streaming-only) must use the cluster store, not
+		// an empty-named replica source key.
+		Entry("current primary without a replica source -> cluster store",
+			newConfig(instance, ""),
+			"cluster-server", "cluster-store"),
+
+		// Bootstrap / PITR: no current primary yet. Recovery wins even if a replica
+		// source happens to be configured.
+		Entry("no current primary -> recovery store",
+			newConfig("", "replica-store"),
+			"recovery-server", "recovery-store"),
+
+		Entry("ordinary standby -> cluster store",
+			newConfig("cluster-2", ""),
+			"cluster-server", "cluster-store"),
+
+		// A non-primary instance must never route to the replica source, even when
+		// one is configured: only the designated primary catches up from the source.
+		Entry("standby in a replica cluster -> cluster store",
+			newConfig("cluster-2", "replica-store"),
+			"cluster-server", "cluster-store"),
+	)
+})