fix(instance): Fix block volume detach when no additional volumes remaining

scaleway/resource_instance_server.go

@@ -677,12 +677,16 @@ func resourceScalewayInstanceServerUpdate(ctx context.Context, d *schema.Resourc
 
 	volumes := map[string]*instance.VolumeServerTemplate{}
 
-	if raw, ok := d.GetOk("additional_volume_ids"); d.HasChange("additional_volume_ids") && ok {
+	if raw, hasVolumes := d.GetOk("additional_volume_ids"); d.HasChange("additional_volume_ids") {
 		volumes["0"] = &instance.VolumeServerTemplate{
 			ID:   expandZonedID(d.Get("root_volume.0.volume_id")).ID,
 			Name: newRandomName("vol"), // name is ignored by the API, any name will work here
 		}
 
+		if !hasVolumes {
+			raw = []interface{}{} // Set an empty list if not volumes exist
+		}
+
 		for i, volumeID := range raw.([]interface{}) {
 			volumeHasChange := d.HasChange("additional_volume_ids." + strconv.Itoa(i))
 			// local volumes can only be added when the instance is stopped

scaleway/resource_instance_server_test.go

@@ -543,6 +543,73 @@ func TestAccScalewayInstanceServer_AdditionalVolumes(t *testing.T) {
 	})
 }
 
+func TestAccScalewayInstanceServer_AdditionalVolumesDetach(t *testing.T) {
+	tt := NewTestTools(t)
+	defer tt.Cleanup()
+	resource.Test(t, resource.TestCase{
+		PreCheck:          func() { testAccPreCheck(t) },
+		ProviderFactories: tt.ProviderFactories,
+		CheckDestroy: resource.ComposeTestCheckFunc(
+			testAccCheckScalewayInstanceVolumeDestroy(tt),
+			testAccCheckScalewayInstanceServerDestroy(tt),
+		),
+		Steps: []resource.TestStep{
+			{
+				Config: `
+					variable "zone" {
+						type    = string
+						default = "fr-par-1"
+					}
+
+					resource "scaleway_instance_volume" "main" {
+  						type       = "b_ssd"
+  						name       = "foobar"
+  						size_in_gb = 1
+					}
+
+					resource "scaleway_instance_server" "main" {
+						type  = "DEV1-S"
+  						image = "ubuntu_focal"
+  						name  = "foobar"
+
+						enable_dynamic_ip = true
+
+						additional_volume_ids = [scaleway_instance_volume.main.id]
+					}
+				`,
+			},
+			{
+				Config: `
+					variable "zone" {
+						type    = string
+						default = "fr-par-1"
+					}
+
+					resource "scaleway_instance_volume" "main" {
+  						type       = "b_ssd"
+  						name       = "foobar"
+  						size_in_gb = 1
+					}
+
+					resource "scaleway_instance_server" "main" {
+						type  = "DEV1-S"
+  						image = "ubuntu_focal"
+  						name  = "foobar"
+
+						enable_dynamic_ip = true
+
+						additional_volume_ids = []
+					}
+				`,
+				Check: resource.ComposeTestCheckFunc(
+					testAccCheckScalewayInstanceVolumeExists(tt, "scaleway_instance_volume.main"),
+					resource.TestCheckResourceAttr("scaleway_instance_server.main", "additional_volume_ids.#", "0"),
+				),
+			},
+		},
+	})
+}
+
 func TestAccScalewayInstanceServer_WithPlacementGroup(t *testing.T) {
 	tt := NewTestTools(t)
 	defer tt.Cleanup()

scaleway/resource_instance_volume.go

@@ -238,18 +238,20 @@ func resourceScalewayInstanceVolumeDelete(ctx context.Context, d *schema.Resourc
 	}
 
 	err = resource.Retry(d.Timeout(schema.TimeoutDelete), func() *resource.RetryError {
-		volumeResp, err := instanceAPI.GetVolume(&instance.GetVolumeRequest{
-			Zone:     zone,
-			VolumeID: id,
-		})
+		volume, err := instanceAPI.WaitForVolume(&instance.WaitForVolumeRequest{
+			Zone:          zone,
+			VolumeID:      id,
+			RetryInterval: DefaultWaitRetryInterval,
+			Timeout:       scw.TimeDurationPtr(d.Timeout(schema.TimeoutCreate)),
+		}, scw.WithContext(ctx))
 		if err != nil {
 			if is404Error(err) {
 				return nil
 			}
 			return resource.NonRetryableError(err)
 		}
 
-		if volumeResp.Volume.Server != nil {
+		if volume.Server != nil {
 			return resource.RetryableError(fmt.Errorf("volume is still attached to a server"))
 		}