Add nakedret linter.

Signed-off-by: Daniel Nephin <dnephin@docker.com>

cli/command/cli.go

@@ -207,7 +207,8 @@ func NewAPIClientFromFlags(opts *cliflags.CommonOptions, configFile *configfile.
 	return client.NewClient(host, verStr, httpClient, customHeaders)
 }
 
-func getServerHost(hosts []string, tlsOptions *tlsconfig.Options) (host string, err error) {
+func getServerHost(hosts []string, tlsOptions *tlsconfig.Options) (string, error) {
+	var host string
 	switch len(hosts) {
 	case 0:
 		host = os.Getenv("DOCKER_HOST")
@@ -217,8 +218,7 @@ func getServerHost(hosts []string, tlsOptions *tlsconfig.Options) (host string,
 		return "", errors.New("Please specify only one -H")
 	}
 
-	host, err = dopts.ParseHost(tlsOptions != nil, host)
+	return dopts.ParseHost(tlsOptions != nil, host)
-	return
 }
 
 func newHTTPClient(host string, tlsOptions *tlsconfig.Options) (*http.Client, error) {

cli/command/container/prune.go

@@ -52,12 +52,12 @@ func runPrune(dockerCli command.Cli, options pruneOptions) (spaceReclaimed uint6
 	pruneFilters := command.PruneFilters(dockerCli, options.filter.Value())
 
 	if !options.force && !command.PromptForConfirmation(dockerCli.In(), dockerCli.Out(), warning) {
-		return
+		return 0, "", nil
 	}
 
 	report, err := dockerCli.Client().ContainersPrune(context.Background(), pruneFilters)
 	if err != nil {
-		return
+		return 0, "", err
 	}
 
 	if len(report.ContainersDeleted) > 0 {
@@ -68,7 +68,7 @@ func runPrune(dockerCli command.Cli, options pruneOptions) (spaceReclaimed uint6
 		spaceReclaimed = report.SpaceReclaimed
 	}
 
-	return
+	return spaceReclaimed, output, nil
 }
 
 // RunPrune calls the Container Prune API

cli/command/container/stats_helpers.go

@@ -200,7 +200,8 @@ func calculateCPUPercentWindows(v *types.StatsJSON) float64 {
 	return 0.00
 }
 
-func calculateBlockIO(blkio types.BlkioStats) (blkRead uint64, blkWrite uint64) {
+func calculateBlockIO(blkio types.BlkioStats) (uint64, uint64) {
+	var blkRead, blkWrite uint64
 	for _, bioEntry := range blkio.IoServiceBytesRecursive {
 		switch strings.ToLower(bioEntry.Op) {
 		case "read":
@@ -209,7 +210,7 @@ func calculateBlockIO(blkio types.BlkioStats) (blkRead uint64, blkWrite uint64)
 			blkWrite = blkWrite + bioEntry.Value
 		}
 	}
-	return
+	return blkRead, blkWrite
 }
 
 func calculateNetwork(network map[string]types.NetworkStats) (float64, float64) {

cli/command/formatter/disk_usage.go

@@ -118,11 +118,11 @@ func (ctx *DiskUsageContext) Write() (err error) {
 	return err
 }
 
-func (ctx *DiskUsageContext) verboseWrite() (err error) {
+func (ctx *DiskUsageContext) verboseWrite() error {
 	// First images
 	tmpl, err := ctx.startSubsection(defaultDiskUsageImageTableFormat)
 	if err != nil {
-		return
+		return err
 	}
 
 	ctx.Output.Write([]byte("Images space usage:\n\n"))
@@ -141,14 +141,14 @@ func (ctx *DiskUsageContext) verboseWrite() (err error) {
 			}
 		}
 
-		err = ctx.contextFormat(tmpl, &imageContext{
+		err := ctx.contextFormat(tmpl, &imageContext{
 			repo:  repo,
 			tag:   tag,
 			trunc: true,
 			i:     *i,
 		})
 		if err != nil {
-			return
+			return err
 		}
 	}
 	ctx.postFormat(tmpl, newImageContext())
@@ -157,17 +157,14 @@ func (ctx *DiskUsageContext) verboseWrite() (err error) {
 	ctx.Output.Write([]byte("\nContainers space usage:\n\n"))
 	tmpl, err = ctx.startSubsection(defaultDiskUsageContainerTableFormat)
 	if err != nil {
-		return
+		return err
 	}
 	for _, c := range ctx.Containers {
 		// Don't display the virtual size
 		c.SizeRootFs = 0
-		err = ctx.contextFormat(tmpl, &containerContext{
+		err := ctx.contextFormat(tmpl, &containerContext{trunc: true, c: *c})
-			trunc: true,
-			c:     *c,
-		})
 		if err != nil {
-			return
+			return err
 		}
 	}
 	ctx.postFormat(tmpl, newContainerContext())
@@ -176,21 +173,18 @@ func (ctx *DiskUsageContext) verboseWrite() (err error) {
 	ctx.Output.Write([]byte("\nLocal Volumes space usage:\n\n"))
 	tmpl, err = ctx.startSubsection(defaultDiskUsageVolumeTableFormat)
 	if err != nil {
-		return
+		return err
 	}
 	for _, v := range ctx.Volumes {
-		err = ctx.contextFormat(tmpl, &volumeContext{
+		if err := ctx.contextFormat(tmpl, &volumeContext{v: *v}); err != nil {
-			v: *v,
+			return err
-		})
-		if err != nil {
-			return
 		}
 	}
 	ctx.postFormat(tmpl, newVolumeContext())
 
 	// And build cache
 	fmt.Fprintf(ctx.Output, "\nBuild cache usage: %s\n\n", units.HumanSize(float64(ctx.BuilderSize)))
-	return
+	return nil
 }
 
 type diskUsageImagesContext struct {

cli/command/image/build_session.go

@@ -128,18 +128,18 @@ func getBuildSharedKey(dir string) (string, error) {
 	return hex.EncodeToString(s[:]), nil
 }
 
-func tryNodeIdentifier() (out string) {
+func tryNodeIdentifier() string {
-	out = cliconfig.Dir() // return config dir as default on permission error
+	out := cliconfig.Dir() // return config dir as default on permission error
 	if err := os.MkdirAll(cliconfig.Dir(), 0700); err == nil {
 		sessionFile := filepath.Join(cliconfig.Dir(), ".buildNodeID")
 		if _, err := os.Lstat(sessionFile); err != nil {
 			if os.IsNotExist(err) { // create a new file with stored randomness
 				b := make([]byte, 32)
 				if _, err := rand.Read(b); err != nil {
-					return
+					return out
 				}
 				if err := ioutil.WriteFile(sessionFile, []byte(hex.EncodeToString(b)), 0600); err != nil {
-					return
+					return out
 				}
 			}
 		}
@@ -149,5 +149,5 @@ func tryNodeIdentifier() (out string) {
 			return string(dt)
 		}
 	}
-	return
+	return out
 }

cli/command/image/prune.go

@@ -65,12 +65,12 @@ func runPrune(dockerCli command.Cli, options pruneOptions) (spaceReclaimed uint6
 		warning = allImageWarning
 	}
 	if !options.force && !command.PromptForConfirmation(dockerCli.In(), dockerCli.Out(), warning) {
-		return
+		return 0, "", nil
 	}
 
 	report, err := dockerCli.Client().ImagesPrune(context.Background(), pruneFilters)
 	if err != nil {
-		return
+		return 0, "", err
 	}
 
 	if len(report.ImagesDeleted) > 0 {
@@ -85,7 +85,7 @@ func runPrune(dockerCli command.Cli, options pruneOptions) (spaceReclaimed uint6
 		spaceReclaimed = report.SpaceReclaimed
 	}
 
-	return
+	return spaceReclaimed, output, nil
 }
 
 // RunPrune calls the Image Prune API

cli/command/network/prune.go

@@ -50,12 +50,12 @@ func runPrune(dockerCli command.Cli, options pruneOptions) (output string, err e
 	pruneFilters := command.PruneFilters(dockerCli, options.filter.Value())
 
 	if !options.force && !command.PromptForConfirmation(dockerCli.In(), dockerCli.Out(), warning) {
-		return
+		return "", nil
 	}
 
 	report, err := dockerCli.Client().NetworksPrune(context.Background(), pruneFilters)
 	if err != nil {
-		return
+		return "", err
 	}
 
 	if len(report.NetworksDeleted) > 0 {
@@ -65,7 +65,7 @@ func runPrune(dockerCli command.Cli, options pruneOptions) (output string, err e
 		}
 	}
 
-	return
+	return output, nil
 }
 
 // RunPrune calls the Network Prune API

cli/command/plugin/install.go

@@ -57,12 +57,12 @@ type pluginRegistryService struct {
 	registry.Service
 }
 
-func (s pluginRegistryService) ResolveRepository(name reference.Named) (repoInfo *registry.RepositoryInfo, err error) {
+func (s pluginRegistryService) ResolveRepository(name reference.Named) (*registry.RepositoryInfo, error) {
-	repoInfo, err = s.Service.ResolveRepository(name)
+	repoInfo, err := s.Service.ResolveRepository(name)
 	if repoInfo != nil {
 		repoInfo.Class = "plugin"
 	}
-	return
+	return repoInfo, err
 }
 
 func newRegistryService() (registry.Service, error) {

cli/command/volume/prune.go

@@ -52,12 +52,12 @@ func runPrune(dockerCli command.Cli, options pruneOptions) (spaceReclaimed uint6
 	pruneFilters := command.PruneFilters(dockerCli, options.filter.Value())
 
 	if !options.force && !command.PromptForConfirmation(dockerCli.In(), dockerCli.Out(), warning) {
-		return
+		return 0, "", nil
 	}
 
 	report, err := dockerCli.Client().VolumesPrune(context.Background(), pruneFilters)
 	if err != nil {
-		return
+		return 0, "", err
 	}
 
 	if len(report.VolumesDeleted) > 0 {
@@ -68,7 +68,7 @@ func runPrune(dockerCli command.Cli, options pruneOptions) (spaceReclaimed uint6
 		spaceReclaimed = report.SpaceReclaimed
 	}
 
-	return
+	return spaceReclaimed, output, nil
 }
 
 // RunPrune calls the Volume Prune API

dockerfiles/Dockerfile.lint

@@ -10,6 +10,13 @@ RUN     go get -d github.com/alecthomas/gometalinter && \
         gometalinter --install && \
         rm -rf /go/src/* /go/pkg/*
 
+ARG     NAKEDRET_SHA=3ddb495a6d63bc9041ba843e7d651cf92639d8cb
+RUN     go get -d github.com/alexkohler/nakedret && \
+        cd /go/src/github.com/alexkohler/nakedret && \
+        git checkout -q "$NAKEDRET_SHA" && \
+        go build -v -o /usr/local/bin/nakedret . && \
+        rm -rf /go/src/* /go/pkg/*
+
 WORKDIR /go/src/github.com/docker/cli
 ENV     CGO_ENABLED=0
 ENV     DISABLE_WARN_OUTSIDE_CONTAINER=1

docs/yaml/yaml.go

@@ -225,7 +225,7 @@ func parseMDContent(mdString string) (description string, examples string) {
 			examples = strings.Trim(s, "Examples\n")
 		}
 	}
-	return
+	return description, examples
 }
 
 type byName []*cobra.Command

gometalinter.json

@@ -7,6 +7,12 @@
       "parameter .* always receives"
   ],
   "EnableGC": true,
+  "Linters": {
+      "nakedret": {
+        "Command": "nakedret",
+        "Pattern": "^(?P<path>.*?\\.go):(?P<line>\\d+)\\s*(?P<message>.*)$"
+      }
+  },
 
   "DisableAll": true,
   "Enable": [
@@ -20,6 +26,7 @@
     "interfacer",
     "lll",
     "misspell",
+    "nakedret",
     "unconvert",
     "unparam",
     "unused",

opts/network.go

@@ -95,12 +95,12 @@ func (n *NetworkOpt) String() string {
 	return ""
 }
 
-func parseDriverOpt(driverOpt string) (key string, value string, err error) {
+func parseDriverOpt(driverOpt string) (string, string, error) {
 	parts := strings.SplitN(driverOpt, "=", 2)
 	if len(parts) != 2 {
-		err = fmt.Errorf("invalid key value pair format in driver options")
+		return "", "", fmt.Errorf("invalid key value pair format in driver options")
 	}
-	key = strings.TrimSpace(strings.ToLower(parts[0]))
+	key := strings.TrimSpace(strings.ToLower(parts[0]))
-	value = strings.TrimSpace(strings.ToLower(parts[1]))
+	value := strings.TrimSpace(strings.ToLower(parts[1]))
-	return
+	return key, value, nil
 }