fix: check if the image was found (#223)

A nil check was missing before using the image object.

Closes #222

builder/hcloud/step_create_server.go

@@ -71,13 +71,23 @@ func (s *stepCreateServer) Run(ctx context.Context, state multistep.StateBag) mu
 		if err != nil {
 			return errorHandler(state, ui, "Could not find image", err)
 		}
+		if image == nil {
+			return errorHandler(state, ui, "", fmt.Errorf("Could not find image"))
+		}
 	} else {
 		image, err = getImageWithSelectors(ctx, client, c, serverType)
 		if err != nil {
 			return errorHandler(state, ui, "Could not find image", err)
 		}
 	}
 	ui.Message(fmt.Sprintf("Using image '%d'", image.ID))
+	if image.IsDeprecated() {
+		ui.Errorf(
+			"The image '%d' is deprecated since the %s and will soon be unavailable",
+			image.ID, image.Deprecated.Format("2006-01-02"),
+		)
+	}
+
 	state.Put(StateSourceImageID, image.ID)
 
 	var networks []*hcloud.Network

builder/hcloud/step_create_server_test.go

@@ -597,6 +597,36 @@ func TestStepCreateServer(t *testing.T) {
 				assert.Regexp(t, "Could not fetch primary ip .*", err.Error())
 			},
 		},
+		{
+			Name:            "fail to get image",
+			Step:            &stepCreateServer{},
+			SetupConfigFunc: func(c *Config) {},
+			SetupStateFunc: func(state multistep.StateBag) {
+				state.Put(StateSSHKeyID, int64(1))
+				state.Put(StateServerType, &hcloud.ServerType{ID: 9, Name: "cpx11", Architecture: "x86"})
+			},
+			WantRequests: []mockutil.Request{
+				{Method: "GET", Path: "/ssh_keys/1",
+					Status: 200,
+					JSONRaw: `{
+						"ssh_key": { "id": 1 }
+					}`,
+				},
+				{Method: "GET", Path: "/images?architecture=x86&include_deprecated=true&name=debian-12",
+					Status: 200,
+					JSONRaw: `{
+						"images": []
+					}`,
+				},
+			},
+			WantStepAction: multistep.ActionHalt,
+			WantStateFunc: func(t *testing.T, state multistep.StateBag) {
+				err, ok := state.Get(StateError).(error)
+				assert.True(t, ok)
+				assert.NotNil(t, err)
+				assert.EqualError(t, err, "Could not find image")
+			},
+		},
 	})
 }