feat: Allow DNS zones with trailing dot

stackit/internal/services/dns/dns_acc_test.go

@@ -83,6 +83,8 @@ func configVarsMaxUpdated() config.Variables {
 }
 
 func TestAccDnsMinResource(t *testing.T) {
+	dotDnsName := "tf-acc-" + acctest.RandStringFromCharSet(8, acctest.CharSetAlpha) + ".example.home."
+
 	resource.ParallelTest(t, resource.TestCase{
 		ProtoV6ProviderFactories: testutil.TestAccProtoV6ProviderFactories,
 		CheckDestroy:             testAccCheckDnsDestroy,
@@ -247,6 +249,20 @@ func TestAccDnsMinResource(t *testing.T) {
 					resource.TestCheckResourceAttrSet("stackit_dns_record_set.record_set", "fqdn"),
 					resource.TestCheckResourceAttrSet("stackit_dns_record_set.record_set", "state")),
 			},
+			// Test trailing dot preservation
+			{
+				Config: resourceMinConfig,
+				ConfigVariables: func() config.Variables {
+					vars := maps.Clone(testConfigVarsMin)
+					vars["dns_name"] = config.StringVariable(dotDnsName)
+					return vars
+				}(),
+				Check: resource.ComposeAggregateTestCheckFunc(
+					resource.TestCheckResourceAttr("stackit_dns_zone.zone", "project_id", testutil.ProjectId),
+					// Verify that the state has the trailing dot, matching the config
+					resource.TestCheckResourceAttr("stackit_dns_zone.zone", "dns_name", dotDnsName),
+				),
+			},
 			// Deletion is done by the framework implicitly
 		},
 	})

stackit/internal/services/dns/zone/resource.go

@@ -537,7 +537,7 @@ func mapFields(ctx context.Context, zoneResp *dns.ZoneResponse, model *Model) er
 	model.Active = types.BoolPointerValue(z.Active)
 	model.ContactEmail = types.StringPointerValue(z.ContactEmail)
 	model.DefaultTTL = types.Int64PointerValue(z.DefaultTTL)
-	model.DnsName = types.StringPointerValue(z.DnsName)
+	model.DnsName = reconcileDnsName(model.DnsName, z.DnsName)
 	model.ExpireTime = types.Int64PointerValue(z.ExpireTime)
 	model.IsReverseZone = types.BoolPointerValue(z.IsReverseZone)
 	model.Name = types.StringPointerValue(z.Name)
@@ -566,9 +566,16 @@ func toCreatePayload(model *Model) (*dns.CreateZonePayload, error) {
 		}
 		modelPrimaries = append(modelPrimaries, primaryString.ValueString())
 	}
+
+	dnsName := conversion.StringValueToPointer(model.DnsName)
+	if dnsName != nil && strings.HasSuffix(*dnsName, ".") {
+		trimmed := strings.TrimSuffix(*dnsName, ".")
+		dnsName = &trimmed
+	}
+
 	return &dns.CreateZonePayload{
 		Name:          conversion.StringValueToPointer(model.Name),
-		DnsName:       conversion.StringValueToPointer(model.DnsName),
+		DnsName:       dnsName,
 		ContactEmail:  conversion.StringValueToPointer(model.ContactEmail),
 		Description:   conversion.StringValueToPointer(model.Description),
 		Acl:           conversion.StringValueToPointer(model.Acl),
@@ -601,3 +608,27 @@ func toUpdatePayload(model *Model) (*dns.PartialUpdateZonePayload, error) {
 		Primaries:     nil, // API returns error if this field is set, even if nothing changes
 	}, nil
 }
+
+func reconcileDnsName(stateDnsName types.String, apiDnsName *string) types.String {
+	if apiDnsName == nil {
+		return types.StringNull()
+	}
+
+	apiValue := *apiDnsName
+
+	if stateDnsName.IsNull() || stateDnsName.IsUnknown() {
+		return types.StringValue(apiValue)
+	}
+
+	stateValue := stateDnsName.ValueString()
+
+	// If state has trailing dot, but API doesn't
+	if strings.HasSuffix(stateValue, ".") && !strings.HasSuffix(apiValue, ".") {
+		trimmedState := strings.TrimSuffix(stateValue, ".")
+		if trimmedState == apiValue {
+			return stateDnsName // Keep the state value with the dot
+		}
+	}
+
+	return types.StringValue(apiValue)
+}

stackit/internal/services/dns/zone/resource_test.go

@@ -185,6 +185,40 @@ func TestMapFields(t *testing.T) {
 			},
 			true,
 		},
+		{
+			"preserve_trailing_dot",
+			Model{
+				ProjectId: types.StringValue("pid"),
+				ZoneId:    types.StringValue("zid"),
+				DnsName:   types.StringValue("example.com."),
+			},
+			&dns.ZoneResponse{
+				Zone: &dns.Zone{
+					Id:      utils.Ptr("zid"),
+					DnsName: utils.Ptr("example.com"),
+				},
+			},
+			Model{
+				Id:                types.StringValue("pid,zid"),
+				ProjectId:         types.StringValue("pid"),
+				ZoneId:            types.StringValue("zid"),
+				Name:              types.StringNull(),
+				DnsName:           types.StringValue("example.com."),
+				Acl:               types.StringNull(),
+				DefaultTTL:        types.Int64Null(),
+				ExpireTime:        types.Int64Null(),
+				RefreshTime:       types.Int64Null(),
+				RetryTime:         types.Int64Null(),
+				SerialNumber:      types.Int64Null(),
+				NegativeCache:     types.Int64Null(),
+				Type:              types.StringValue(""),
+				State:             types.StringValue(""),
+				PrimaryNameServer: types.StringNull(),
+				Primaries:         types.ListNull(types.StringType),
+				Visibility:        types.StringValue(""),
+			},
+			true,
+		},
 		{
 			"nullable_fields_and_int_conversions_ok",
 			Model{
@@ -345,6 +379,19 @@ func TestToCreatePayload(t *testing.T) {
 			nil,
 			false,
 		},
+		{
+			"with_trailing_dot",
+			&Model{
+				Name:    types.StringValue("Name"),
+				DnsName: types.StringValue("example.com."),
+			},
+			&dns.CreateZonePayload{
+				Name:      utils.Ptr("Name"),
+				DnsName:   utils.Ptr("example.com"),
+				Primaries: &[]string{},
+			},
+			true,
+		},
 	}
 	for _, tt := range tests {
 		t.Run(tt.description, func(t *testing.T) {