chore: introduces golangci-lint (#32)

* refactor: fix code with golangci-lint
* ci: configure golangci-lint
* Closes #13

.github/workflows/golangci-lint.yaml

@@ -0,0 +1,17 @@
+---
+name: golangci-lint
+on:
+  push:
+    branches:
+      - master
+  pull_request:
+jobs:
+  golangci:
+    name: lint
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - name: golangci-lint
+        uses: golangci/golangci-lint-action@v2
+        with:
+          version: v1.33

.golangci.yml

@@ -0,0 +1,7 @@
+linters-settings:
+  errcheck:
+    # https://github.com/hashicorp/terraform-provider-aws/blob/9c9a116a857fb838a0e7d1cfbf420c2524f0abe1/.golangci.yml#L37-L39
+    ignore: github.com/hashicorp/terraform-plugin-sdk/helper/schema:ForceNew|Set,fmt:.*,io:Close
+
+run:
+  timeout: 10m

docker/config.go

@@ -38,7 +38,7 @@ func buildHTTPClientFromBytes(caPEMCert, certPEMBlock, keyPEMBlock []byte) (*htt
 		tlsConfig.Certificates = []tls.Certificate{tlsCert}
 	}
 
-	if caPEMCert == nil || len(caPEMCert) == 0 {
+	if len(caPEMCert) == 0 {
 		tlsConfig.InsecureSkipVerify = true
 	} else {
 		caPool := x509.NewCertPool()

docker/data_source_docker_network.go

@@ -110,7 +110,7 @@ func dataSourceDockerNetworkRead(d *schema.ResourceData, meta interface{}) error
 			"ip_range":    config.IPRange,
 		}
 	}
-	err = d.Set("ipam_config", ipam)
+	d.Set("ipam_config", ipam)
 
 	return nil
 }

docker/resource_docker_container_funcs.go

@@ -559,7 +559,9 @@ func resourceDockerContainerRead(d *schema.ResourceData, meta interface{}) error
 		if finishTime.After(creationTime) {
 			// It exited immediately, so error out so dependent containers
 			// aren't started
-			resourceDockerContainerDelete(d, meta)
+			if err := resourceDockerContainerDelete(d, meta); err != nil {
+				log.Printf("[ERROR] Container %s failed to be deleted: %v", apiContainer.ID, err)
+			}
 			return fmt.Errorf("Container %s exited after creation, error was: %s", apiContainer.ID, container.State.Error)
 		}
 
@@ -568,7 +570,9 @@ func resourceDockerContainerRead(d *schema.ResourceData, meta interface{}) error
 
 	// Handle the case of the for loop above running its course
 	if !container.State.Running && d.Get("must_run").(bool) {
-		resourceDockerContainerDelete(d, meta)
+		if err := resourceDockerContainerDelete(d, meta); err != nil {
+			log.Printf("[ERROR] Container %s failed to be deleted: %v", apiContainer.ID, err)
+		}
 		return fmt.Errorf("Container %s failed to be in running state", apiContainer.ID)
 	}
 

docker/resource_docker_container_migrate.go

@@ -97,7 +97,7 @@ func updateV0ToV1PortsOrder(is *terraform.InstanceState, meta interface{}) error
 	// map the sorted ports to an output structure tf can write
 	outputPorts := make([]interface{}, 0)
 	for _, mappedPort := range portsMapped {
-		outputPort := make(map[string]interface{}, 0)
+		outputPort := make(map[string]interface{})
 		outputPort["internal"] = mappedPort.internal
 		outputPort["external"] = mappedPort.external
 		outputPort["ip"] = mappedPort.ip

docker/resource_docker_container_test.go

@@ -667,7 +667,9 @@ func TestAccDockerContainer_upload(t *testing.T) {
 		}
 
 		fbuf := new(bytes.Buffer)
-		fbuf.ReadFrom(tr)
+		if _, err := fbuf.ReadFrom(tr); err != nil {
+			return err
+		}
 		content := fbuf.String()
 
 		if content != "foo" {
@@ -729,7 +731,9 @@ func TestAccDockerContainer_uploadSource(t *testing.T) {
 		}
 
 		fbuf := new(bytes.Buffer)
-		fbuf.ReadFrom(tr)
+		if _, err := fbuf.ReadFrom(tr); err != nil {
+			return err
+		}
 		content := fbuf.String()
 		if content != string(testFileContent) {
 			return fmt.Errorf("file content is invalid")
@@ -831,7 +835,9 @@ func TestAccDockerContainer_uploadAsBase64(t *testing.T) {
 			}
 
 			fbuf := new(bytes.Buffer)
-			fbuf.ReadFrom(tr)
+			if _, err := fbuf.ReadFrom(tr); err != nil {
+				return err
+			}
 			gotContent := fbuf.String()
 
 			if wantedContent != gotContent {
@@ -982,7 +988,9 @@ func TestAccDockerContainer_device(t *testing.T) {
 		}
 
 		fbuf := new(bytes.Buffer)
-		fbuf.ReadFrom(tr)
+		if _, err := fbuf.ReadFrom(tr); err != nil {
+			return err
+		}
 		content := fbuf.Bytes()
 
 		if len(content) != 10 {

docker/resource_docker_image_funcs.go

@@ -39,7 +39,9 @@ func decodeBuildMessages(response types.ImageBuildResponse) (string, error) {
 			return buf.String(), fmt.Errorf("Problem decoding message from docker daemon: %s", err)
 		}
 
-		m.Display(buf, false)
+		if err := m.Display(buf, false); err != nil {
+			return "", err
+		}
 
 		if m.Error != nil {
 			buildErr = fmt.Errorf("Unable to build image")
@@ -126,7 +128,6 @@ func searchLocalImages(data Data, imageName string) *types.ImageSummary {
 	}
 	if apiImage, ok := data.DockerImages[imageName+":latest"]; ok {
 		log.Printf("[DEBUG] found local image via imageName + latest: %v", imageName)
-		imageName = imageName + ":latest"
 		return apiImage
 	}
 	return nil
@@ -218,7 +219,9 @@ func pullImage(data *Data, client *client.Client, authConfig *AuthConfigs, image
 	defer out.Close()
 
 	buf := new(bytes.Buffer)
-	buf.ReadFrom(out)
+	if _, err := buf.ReadFrom(out); err != nil {
+		return err
+	}
 	s := buf.String()
 	log.Printf("[DEBUG] pulled image %v: %v", image, s)
 

docker/resource_docker_image_test.go

@@ -206,7 +206,9 @@ func testAccDockerImageDestroy(s *terraform.State) error {
 func TestAccDockerImage_build(t *testing.T) {
 	wd, _ := os.Getwd()
 	dfPath := path.Join(wd, "Dockerfile")
-	ioutil.WriteFile(dfPath, []byte(testDockerFileExample), 0o644)
+	if err := ioutil.WriteFile(dfPath, []byte(testDockerFileExample), 0o644); err != nil {
+		t.Fatalf("failed to create a Dockerfile %s for test: %+v", dfPath, err)
+	}
 	defer os.Remove(dfPath)
 	resource.Test(t, resource.TestCase{
 		PreCheck:     func() { testAccPreCheck(t) },

docker/resource_docker_network.go

@@ -249,7 +249,7 @@ func resourceDockerNetworkV0() *schema.Resource {
 	}
 }
 
-func suppressIfIPAMConfigWithIpv6Changes() schema.SchemaDiffSuppressFunc {
+func suppressIfIPAMConfigWithIpv6Changes() schema.SchemaDiffSuppressFunc { //nolint:deadcode,unused
 	return func(k, old, new string, d *schema.ResourceData) bool {
 		// the initial case when the resource is created
 		if old == "" && new != "" {

docker/resource_docker_network_funcs.go

@@ -206,7 +206,7 @@ func resourceDockerNetworkRemoveRefreshFunc(
 // TODO mavogel: separate structure file
 // TODO 2: seems like we can replace the set hash generation with plain lists -> #219
 func flattenIpamConfigSpec(in []network.IPAMConfig) *schema.Set { // []interface{} {
-	out := make([]interface{}, len(in), len(in))
+	out := make([]interface{}, len(in))
 	for i, v := range in {
 		log.Printf("[DEBUG] flatten ipam %d: %#v", i, v)
 		m := make(map[string]interface{})

docker/resource_docker_network_test.go

@@ -259,7 +259,7 @@ func TestAccDockerNetwork_ipv6(t *testing.T) {
 	})
 }
 
-func testAccNetworkIPv6(network *types.NetworkResource, internal bool) resource.TestCheckFunc {
+func testAccNetworkIPv6(network *types.NetworkResource, internal bool) resource.TestCheckFunc { //nolint:unused
 	return func(s *terraform.State) error {
 		if !network.EnableIPv6 {
 			return fmt.Errorf("Bad value for attribute 'ipv6': %t", network.EnableIPv6)
@@ -317,7 +317,7 @@ func TestAccDockerNetwork_labels(t *testing.T) {
 	})
 }
 
-func testAccNetworkLabel(network *types.NetworkResource, name string, value string) resource.TestCheckFunc {
+func testAccNetworkLabel(network *types.NetworkResource, name string, value string) resource.TestCheckFunc { //nolint:deadcode,unused
 	return func(s *terraform.State) error {
 		if network.Labels[name] != value {
 			return fmt.Errorf("Bad value for label '%s': %s", name, network.Labels[name])

docker/resource_docker_registry_image_funcs.go

@@ -178,6 +178,9 @@ func buildDockerRegistryImage(client *client.Client, buildOptions map[string]int
 	}
 	defer os.Remove(dockerContextTarPath)
 	dockerBuildContext, err := os.Open(dockerContextTarPath)
+	if err != nil {
+		return err
+	}
 	defer dockerBuildContext.Close()
 
 	buildResponse, err := client.ImageBuild(context.Background(), dockerBuildContext, imageBuildOptions)
@@ -210,7 +213,7 @@ func buildDockerImageContextTar(buildContext string) (string, error) {
 	tw := tar.NewWriter(tmpFile)
 	defer tw.Close()
 
-	err = filepath.Walk(buildContext, func(file string, info os.FileInfo, err error) error {
+	if err := filepath.Walk(buildContext, func(file string, info os.FileInfo, err error) error {
 		// return on any error
 		if err != nil {
 			return err
@@ -251,7 +254,9 @@ func buildDockerImageContextTar(buildContext string) (string, error) {
 		f.Close()
 
 		return nil
-	})
+	}); err != nil {
+		return "", err
+	}
 
 	return tmpFile.Name(), nil
 }
@@ -262,7 +267,9 @@ func getDockerImageContextTarHash(dockerContextTarPath string) (string, error) {
 	if err != nil {
 		return "", err
 	}
-	hasher.Write(s)
+	if _, err := hasher.Write(s); err != nil {
+		return "", err
+	}
 	contextHash := hex.EncodeToString(hasher.Sum(nil))
 	return contextHash, nil
 }
@@ -295,7 +302,9 @@ func pushDockerRegistryImage(client *client.Client, pushOpts internalPushImageOp
 		if err == io.EOF {
 			break
 		}
-		json.Unmarshal(streamBytes, &errorMessage)
+		if err := json.Unmarshal(streamBytes, &errorMessage); err != nil {
+			return err
+		}
 		if errorMessage.Error != "" {
 			return fmt.Errorf("Error pushing image: %s", errorMessage.Error)
 		}
@@ -401,6 +410,9 @@ func deleteDockerRegistryImage(pushOpts internalPushImageOptions, sha256Digest,
 
 			req.Header.Set("Authorization", "Bearer "+token.Token)
 			oauthResp, err := client.Do(req)
+			if err != nil {
+				return err
+			}
 			switch oauthResp.StatusCode {
 			case http.StatusOK, http.StatusAccepted, http.StatusNotFound:
 				return nil

docker/resource_docker_service_funcs.go

@@ -1135,7 +1135,8 @@ func createLogDriver(v interface{}) (*swarm.Driver, error) {
 			if rawOptions, ok := rawLogging["options"]; ok {
 				logDriver.Options = mapTypeMapValsToString(rawOptions.(map[string]interface{}))
 			}
-			return &logDriver, nil
+			// TODO SA4004: the surrounding loop is unconditionally terminated (staticcheck)
+			return &logDriver, nil //nolint:staticcheck
 		}
 	}
 	return nil, nil
@@ -1329,7 +1330,7 @@ func fromRegistryAuth(image string, authConfigs map[string]types.AuthConfig) typ
 
 // retrieveAndMarshalAuth retrieves and marshals the service registry auth
 func retrieveAndMarshalAuth(d *schema.ResourceData, meta interface{}, stageType string) []byte {
-	auth := types.AuthConfig{}
+	var auth types.AuthConfig
 	if v, ok := d.GetOk("auth"); ok {
 		auth = authToServiceAuth(v.(map[string]interface{}))
 	} else {
@@ -1407,8 +1408,6 @@ var (
 		swarm.TaskStateFailed:   12,
 		swarm.TaskStateRejected: 13,
 	}
-
-	longestState int
 )
 
 // serviceCreatePendingStates are the pending states for the creation of a service

docker/resource_docker_service_test.go

@@ -63,12 +63,10 @@ func TestDockerSecretFromRegistryAuth_multiple(t *testing.T) {
 	checkAttribute(t, "ServerAddress", foundAuthConfig.ServerAddress, "")
 }
 
-func checkAttribute(t *testing.T, name, actual, expected string) error {
+func checkAttribute(t *testing.T, name, actual, expected string) {
 	if actual != expected {
 		t.Fatalf("bad authconfig attribute for '%q'\nExpected: %s\n     Got: %s", name, expected, actual)
 	}
-
-	return nil
 }
 
 func TestDockerImageNameSuppress(t *testing.T) {

docker/resource_docker_volume_test.go

@@ -92,7 +92,7 @@ func TestAccDockerVolume_labels(t *testing.T) {
 	})
 }
 
-func testAccVolumeLabel(volume *types.Volume, name string, value string) resource.TestCheckFunc {
+func testAccVolumeLabel(volume *types.Volume, name string, value string) resource.TestCheckFunc { //nolint:deadcode,unused
 	return func(s *terraform.State) error {
 		if volume.Labels[name] != value {
 			return fmt.Errorf("Bad value for label '%s': %s", name, volume.Labels[name])

docker/structures_service.go

@@ -25,9 +25,7 @@ func flattenTaskSpec(in swarm.TaskSpec) []interface{} {
 	if in.Placement != nil {
 		m["placement"] = flattenTaskPlacement(in.Placement)
 	}
-	if in.ForceUpdate >= 0 {
-		m["force_update"] = in.ForceUpdate
-	}
+	m["force_update"] = in.ForceUpdate
 	if len(in.Runtime) > 0 {
 		m["runtime"] = in.Runtime
 	}
@@ -56,7 +54,7 @@ func flattenServiceMode(in swarm.ServiceMode) []interface{} {
 }
 
 func flattenReplicated(in *swarm.ReplicatedService) []interface{} {
-	out := make([]interface{}, 0, 0)
+	out := make([]interface{}, 0)
 	m := make(map[string]interface{})
 	if in != nil {
 		if in.Replicas != nil {
@@ -69,7 +67,7 @@ func flattenReplicated(in *swarm.ReplicatedService) []interface{} {
 }
 
 func flattenServiceUpdateOrRollbackConfig(in *swarm.UpdateConfig) []interface{} {
-	out := make([]interface{}, 0, 0)
+	out := make([]interface{}, 0)
 	if in == nil {
 		return out
 	}
@@ -86,7 +84,7 @@ func flattenServiceUpdateOrRollbackConfig(in *swarm.UpdateConfig) []interface{}
 }
 
 func flattenServiceEndpoint(in swarm.Endpoint) []interface{} {
-	out := make([]interface{}, 0, 0)
+	out := make([]interface{}, 0)
 	m := make(map[string]interface{})
 	m["mode"] = string(in.Spec.Mode)
 	m["ports"] = flattenServicePorts(in.Ports)
@@ -96,7 +94,7 @@ func flattenServiceEndpoint(in swarm.Endpoint) []interface{} {
 }
 
 func flattenServiceEndpointSpec(in *swarm.EndpointSpec) []interface{} {
-	out := make([]interface{}, 0, 0)
+	out := make([]interface{}, 0)
 	m := make(map[string]interface{})
 	m["mode"] = string(in.Mode)
 	m["ports"] = flattenServicePorts(in.Ports)
@@ -107,7 +105,7 @@ func flattenServiceEndpointSpec(in *swarm.EndpointSpec) []interface{} {
 
 ///// start TaskSpec
 func flattenContainerSpec(in *swarm.ContainerSpec) []interface{} {
-	out := make([]interface{}, 0, 0)
+	out := make([]interface{}, 0)
 	m := make(map[string]interface{})
 	if len(in.Image) > 0 {
 		m["image"] = in.Image
@@ -175,14 +173,14 @@ func flattenContainerSpec(in *swarm.ContainerSpec) []interface{} {
 
 func flattenPrivileges(in *swarm.Privileges) []interface{} {
 	if in == nil {
-		return make([]interface{}, 0, 0)
+		return make([]interface{}, 0)
 	}
 
-	out := make([]interface{}, 1, 1)
+	out := make([]interface{}, 1)
 	m := make(map[string]interface{})
 
 	if in.CredentialSpec != nil {
-		credSpec := make([]interface{}, 1, 1)
+		credSpec := make([]interface{}, 1)
 		internal := make(map[string]interface{})
 		internal["file"] = in.CredentialSpec.File
 		internal["registry"] = in.CredentialSpec.Registry
@@ -190,7 +188,7 @@ func flattenPrivileges(in *swarm.Privileges) []interface{} {
 		m["credential_spec"] = credSpec
 	}
 	if in.SELinuxContext != nil {
-		seLinuxContext := make([]interface{}, 1, 1)
+		seLinuxContext := make([]interface{}, 1)
 		internal := make(map[string]interface{})
 		internal["disable"] = in.SELinuxContext.Disable
 		internal["user"] = in.SELinuxContext.User
@@ -205,7 +203,7 @@ func flattenPrivileges(in *swarm.Privileges) []interface{} {
 }
 
 func flattenServiceMounts(in []mount.Mount) *schema.Set {
-	out := make([]interface{}, len(in), len(in))
+	out := make([]interface{}, len(in))
 	for i, v := range in {
 		m := make(map[string]interface{})
 		m["target"] = v.Target
@@ -213,8 +211,8 @@ func flattenServiceMounts(in []mount.Mount) *schema.Set {
 		m["type"] = string(v.Type)
 		m["read_only"] = v.ReadOnly
 		if v.BindOptions != nil {
-			bindOptions := make([]interface{}, 0, 0)
-			bindOptionsItem := make(map[string]interface{}, 0)
+			bindOptions := make([]interface{}, 0)
+			bindOptionsItem := make(map[string]interface{})
 
 			if len(v.BindOptions.Propagation) > 0 {
 				bindOptionsItem["propagation"] = string(v.BindOptions.Propagation)
@@ -225,8 +223,8 @@ func flattenServiceMounts(in []mount.Mount) *schema.Set {
 		}
 
 		if v.VolumeOptions != nil {
-			volumeOptions := make([]interface{}, 0, 0)
-			volumeOptionsItem := make(map[string]interface{}, 0)
+			volumeOptions := make([]interface{}, 0)
+			volumeOptionsItem := make(map[string]interface{})
 
 			volumeOptionsItem["no_copy"] = v.VolumeOptions.NoCopy
 			volumeOptionsItem["labels"] = mapToLabelSet(v.VolumeOptions.Labels)
@@ -242,8 +240,8 @@ func flattenServiceMounts(in []mount.Mount) *schema.Set {
 		}
 
 		if v.TmpfsOptions != nil {
-			tmpfsOptions := make([]interface{}, 0, 0)
-			tmpfsOptionsItem := make(map[string]interface{}, 0)
+			tmpfsOptions := make([]interface{}, 0)
+			tmpfsOptionsItem := make(map[string]interface{})
 
 			tmpfsOptionsItem["size_bytes"] = int(v.TmpfsOptions.SizeBytes)
 			tmpfsOptionsItem["mode"] = v.TmpfsOptions.Mode.Perm
@@ -263,10 +261,10 @@ func flattenServiceMounts(in []mount.Mount) *schema.Set {
 
 func flattenServiceHealthcheck(in *container.HealthConfig) []interface{} {
 	if in == nil {
-		return make([]interface{}, 0, 0)
+		return make([]interface{}, 0)
 	}
 
-	out := make([]interface{}, 1, 1)
+	out := make([]interface{}, 1)
 	m := make(map[string]interface{})
 	if len(in.Test) > 0 {
 		m["test"] = in.Test
@@ -280,7 +278,7 @@ func flattenServiceHealthcheck(in *container.HealthConfig) []interface{} {
 }
 
 func flattenServiceHosts(in []string) *schema.Set {
-	out := make([]interface{}, len(in), len(in))
+	out := make([]interface{}, len(in))
 	for i, v := range in {
 		m := make(map[string]interface{})
 		split := strings.Split(v, ":")
@@ -297,10 +295,10 @@ func flattenServiceHosts(in []string) *schema.Set {
 
 func flattenServiceDNSConfig(in *swarm.DNSConfig) []interface{} {
 	if in == nil {
-		return make([]interface{}, 0, 0)
+		return make([]interface{}, 0)
 	}
 
-	out := make([]interface{}, 1, 1)
+	out := make([]interface{}, 1)
 	m := make(map[string]interface{})
 	if len(in.Nameservers) > 0 {
 		m["nameservers"] = in.Nameservers
@@ -316,7 +314,7 @@ func flattenServiceDNSConfig(in *swarm.DNSConfig) []interface{} {
 }
 
 func flattenServiceSecrets(in []*swarm.SecretReference) *schema.Set {
-	out := make([]interface{}, len(in), len(in))
+	out := make([]interface{}, len(in))
 	for i, v := range in {
 		m := make(map[string]interface{})
 		m["secret_id"] = v.SecretID
@@ -343,7 +341,7 @@ func flattenServiceSecrets(in []*swarm.SecretReference) *schema.Set {
 }
 
 func flattenServiceConfigs(in []*swarm.ConfigReference) *schema.Set {
-	out := make([]interface{}, len(in), len(in))
+	out := make([]interface{}, len(in))
 	for i, v := range in {
 		m := make(map[string]interface{})
 		m["config_id"] = v.ConfigID
@@ -370,7 +368,7 @@ func flattenServiceConfigs(in []*swarm.ConfigReference) *schema.Set {
 }
 
 func flattenTaskResources(in *swarm.ResourceRequirements) []interface{} {
-	out := make([]interface{}, 0, 0)
+	out := make([]interface{}, 0)
 	if in != nil {
 		m := make(map[string]interface{})
 		m["limits"] = flattenResourceLimitsOrReservations(in.Limits)
@@ -381,7 +379,7 @@ func flattenTaskResources(in *swarm.ResourceRequirements) []interface{} {
 }
 
 func flattenResourceLimitsOrReservations(in *swarm.Resources) []interface{} {
-	out := make([]interface{}, 0, 0)
+	out := make([]interface{}, 0)
 	if in != nil {
 		m := make(map[string]interface{})
 		m["nano_cpus"] = in.NanoCPUs
@@ -393,8 +391,8 @@ func flattenResourceLimitsOrReservations(in *swarm.Resources) []interface{} {
 }
 
 func flattenResourceGenericResource(in []swarm.GenericResource) []interface{} {
-	out := make([]interface{}, 0, 0)
-	if in != nil && len(in) > 0 {
+	out := make([]interface{}, 0)
+	if len(in) > 0 {
 		m := make(map[string]interface{})
 		named := make([]string, 0)
 		discrete := make([]string, 0)
@@ -433,9 +431,9 @@ func flattenTaskRestartPolicy(in *swarm.RestartPolicy) map[string]interface{} {
 
 func flattenTaskPlacement(in *swarm.Placement) []interface{} {
 	if in == nil {
-		return make([]interface{}, 0, 0)
+		return make([]interface{}, 0)
 	}
-	out := make([]interface{}, 1, 1)
+	out := make([]interface{}, 1)
 	m := make(map[string]interface{})
 	if len(in.Constraints) > 0 {
 		m["constraints"] = newStringSet(schema.HashString, in.Constraints)
@@ -451,11 +449,11 @@ func flattenTaskPlacement(in *swarm.Placement) []interface{} {
 }
 
 func flattenPlacementPrefs(in []swarm.PlacementPreference) *schema.Set {
-	if in == nil || len(in) == 0 {
-		return schema.NewSet(schema.HashString, make([]interface{}, 0, 0))
+	if len(in) == 0 {
+		return schema.NewSet(schema.HashString, make([]interface{}, 0))
 	}
 
-	out := make([]interface{}, len(in), len(in))
+	out := make([]interface{}, len(in))
 	for i, v := range in {
 		out[i] = v.Spread.SpreadDescriptor
 	}
@@ -463,7 +461,7 @@ func flattenPlacementPrefs(in []swarm.PlacementPreference) *schema.Set {
 }
 
 func flattenPlacementPlatforms(in []swarm.Platform) *schema.Set {
-	out := make([]interface{}, len(in), len(in))
+	out := make([]interface{}, len(in))
 	for i, v := range in {
 		m := make(map[string]interface{})
 		m["architecture"] = v.Architecture
@@ -477,7 +475,7 @@ func flattenPlacementPlatforms(in []swarm.Platform) *schema.Set {
 }
 
 func flattenTaskNetworks(in []swarm.NetworkAttachmentConfig) *schema.Set {
-	out := make([]interface{}, len(in), len(in))
+	out := make([]interface{}, len(in))
 	for i, v := range in {
 		out[i] = v.Target
 	}
@@ -486,10 +484,10 @@ func flattenTaskNetworks(in []swarm.NetworkAttachmentConfig) *schema.Set {
 
 func flattenTaskLogDriver(in *swarm.Driver) []interface{} {
 	if in == nil {
-		return make([]interface{}, 0, 0)
+		return make([]interface{}, 0)
 	}
 
-	out := make([]interface{}, 1, 1)
+	out := make([]interface{}, 1)
 	m := make(map[string]interface{})
 	m["name"] = in.Name
 	if len(in.Options) > 0 {
@@ -502,7 +500,7 @@ func flattenTaskLogDriver(in *swarm.Driver) []interface{} {
 ///// end TaskSpec
 ///// start EndpointSpec
 func flattenServicePorts(in []swarm.PortConfig) []interface{} {
-	out := make([]interface{}, len(in), len(in))
+	out := make([]interface{}, len(in))
 	for i, v := range in {
 		m := make(map[string]interface{})
 		m["name"] = v.Name
@@ -530,7 +528,7 @@ func shortDur(d time.Duration) string {
 }
 
 func newStringSet(f schema.SchemaSetFunc, in []string) *schema.Set {
-	out := make([]interface{}, len(in), len(in))
+	out := make([]interface{}, len(in))
 	for i, v := range in {
 		out[i] = v
 	}
@@ -555,8 +553,8 @@ func mapStringSliceToMap(in []string) map[string]string {
 
 // mapStringStringToMapStringInterface maps a string string map to a string interface map
 func mapStringStringToMapStringInterface(in map[string]string) map[string]interface{} {
-	if in == nil || len(in) == 0 {
-		return make(map[string]interface{}, 0)
+	if len(in) == 0 {
+		return make(map[string]interface{})
 	}
 
 	mapped := make(map[string]interface{}, len(in))

docker/validators.go

@@ -49,9 +49,9 @@ func validateFloatRatio() schema.SchemaValidateFunc {
 
 func validateStringIsFloatRatio() schema.SchemaValidateFunc {
 	return func(v interface{}, k string) (ws []string, errors []error) {
-		switch v.(type) {
+		switch t := v.(type) {
 		case string:
-			stringValue := v.(string)
+			stringValue := t
 			value, err := strconv.ParseFloat(stringValue, 64)
 			if err != nil {
 				errors = append(errors, fmt.Errorf(
@@ -62,7 +62,7 @@ func validateStringIsFloatRatio() schema.SchemaValidateFunc {
 					"%q has to be between 0.0 and 1.0", k))
 			}
 		case int:
-			value := float64(v.(int))
+			value := float64(t)
 			if value < 0.0 || value > 1.0 {
 				errors = append(errors, fmt.Errorf(
 					"%q has to be between 0.0 and 1.0", k))