Replicate member_entity_ids and policies in identity/group across nodes identically (#16088)

* Replicate values of group member_entity_ids and policies across nodes identically

* Adding CL

* fixing tests

changelog/16088.txt

@@ -0,0 +1,3 @@
+```release-note:bug
+core/identity: Replicate member_entity_ids and policies in identity/group across nodes identically
+```

vault/external_tests/identity/identity_test.go

@@ -628,8 +628,20 @@ func assertMember(t *testing.T, client *api.Client, entityID, groupName, groupID
 		t.Fatal(err)
 	}
 	groupMap := secret.Data
+
+	groupEntityMembers, ok := groupMap["member_entity_ids"].([]interface{})
+	if !ok && expectFound {
+		t.Fatalf("expected member_entity_ids not to be nil")
+	}
+
+	// if type assertion fails and expectFound is false, groupEntityMembers
+	// is nil, then let's just return, nothing to be done!
+	if !ok && !expectFound {
+		return
+	}
+
 	found := false
-	for _, entityIDRaw := range groupMap["member_entity_ids"].([]interface{}) {
+	for _, entityIDRaw := range groupEntityMembers {
 		if entityIDRaw.(string) == entityID {
 			found = true
 		}

vault/identity_store_util.go

@@ -1473,6 +1473,7 @@ func (i *IdentityStore) sanitizeAndUpsertGroup(ctx context.Context, group *ident
 	}
 
 	// Remove duplicate entity IDs and check if all IDs are valid
+	if group.MemberEntityIDs != nil {
 		group.MemberEntityIDs = strutil.RemoveDuplicates(group.MemberEntityIDs, false)
 		for _, entityID := range group.MemberEntityIDs {
 			entity, err := i.MemDBEntityByID(entityID, false)
@@ -1483,9 +1484,12 @@ func (i *IdentityStore) sanitizeAndUpsertGroup(ctx context.Context, group *ident
 				return fmt.Errorf("invalid entity ID %q", entityID)
 			}
 		}
+	}
 
 	// Remove duplicate policies
+	if group.Policies != nil {
 		group.Policies = strutil.RemoveDuplicates(group.Policies, false)
+	}
 
 	txn := i.db.Txn(true)
 	defer txn.Abort()