enable gocritic linter

The linter ensures a common code style.
- use switch/case instead of else if
- use if instead of switch/case for single case statement
- add space between comment and text
- detect the use of defer with os.Exit()
- use short form var += "..." instead of var = var + "..."
- detect problems with append()
```
newSlice := append(orgSlice, val)
```
  This could lead to nasty bugs because the orgSlice will be changed in
  place if it has enough capacity too hold the new elements. Thus we
  newSlice might not be a copy.

Of course most of the changes are just cosmetic and do not cause any
logic errors but I think it is a good idea to enforce a common style.
This should help maintainability.

Signed-off-by: Paul Holzinger <pholzing@redhat.com>

10 files changed, 30 insertions, 19 deletions

diff --git a/cmd/podman/common/completion.go b/cmd/podman/common/completion.go
index abb943942..c7d5d6d60 100644
--- a/cmd/podman/common/completion.go
+++ b/cmd/podman/common/completion.go
@@ -327,7 +327,7 @@ func suffixCompSlice(suf string, slice []string) []string {
 		if len(split) > 1 {
 			slice[i] = split[0] + suf + "\t" + split[1]
 		} else {
-			slice[i] = slice[i] + suf
+			slice[i] += suf
 		}
 	}
 	return slice
@@ -647,7 +647,10 @@ func AutocompleteInspect(cmd *cobra.Command, args []string, toComplete string) (
 	pods, _ := getPods(cmd, toComplete, completeDefault)
 	networks, _ := getNetworks(cmd, toComplete, completeDefault)
 	volumes, _ := getVolumes(cmd, toComplete)
-	suggestions := append(containers, images...)
+
+	suggestions := make([]string, 0, len(containers)+len(images)+len(pods)+len(networks)+len(volumes))
+	suggestions = append(suggestions, containers...)
+	suggestions = append(suggestions, images...)
 	suggestions = append(suggestions, pods...)
 	suggestions = append(suggestions, networks...)
 	suggestions = append(suggestions, volumes...)
@@ -961,6 +964,8 @@ func AutocompleteFormat(o interface{}) func(cmd *cobra.Command, args []string, t
 	// this function provides shell completion for go templates
 	return func(cmd *cobra.Command, args []string, toComplete string) ([]string, cobra.ShellCompDirective) {
 		// autocomplete json when nothing or json is typed
+		// gocritic complains about the argument order but this is correct in this case
+		//nolint:gocritic
 		if strings.HasPrefix("json", toComplete) {
 			return []string{"json"}, cobra.ShellCompDirectiveNoFileComp
 		}
diff --git a/cmd/podman/common/create.go b/cmd/podman/common/create.go
index 62c9f4c9a..1c1a7c3e3 100644
--- a/cmd/podman/common/create.go
+++ b/cmd/podman/common/create.go
@@ -896,7 +896,7 @@ func DefineCreateFlags(cmd *cobra.Command, cf *entities.ContainerCreateOptions,
 		)
 		_ = cmd.RegisterFlagCompletionFunc(memorySwappinessFlagName, completion.AutocompleteNone)
 	}
-	//anyone can use these
+	// anyone can use these
 	cpusFlagName := "cpus"
 	createFlags.Float64Var(
 		&cf.CPUS,
diff --git a/cmd/podman/completion/completion.go b/cmd/podman/completion/completion.go
index b02a0d772..6f185cde8 100644
--- a/cmd/podman/completion/completion.go
+++ b/cmd/podman/completion/completion.go
@@ -31,7 +31,7 @@ var (
 		Example: `podman completion bash
   podman completion zsh -f _podman
   podman completion fish --no-desc`,
-		//don't show this command to users
+		// don't show this command to users
 		Hidden: true,
 	}
 )
diff --git a/cmd/podman/images/scp.go b/cmd/podman/images/scp.go
index 51a9d1c4e..3dbc9c331 100644
--- a/cmd/podman/images/scp.go
+++ b/cmd/podman/images/scp.go
@@ -121,13 +121,8 @@ func scp(cmd *cobra.Command, args []string) (finalErr error) {
 			return err
 		}
 		if flipConnections { // the order of cliConnections matters, we need to flip both arrays since the args are parsed separately sometimes.
-			connect := cliConnections[0]
-			cliConnections[0] = cliConnections[1]
-			cliConnections[1] = connect
-
-			loc := locations[0]
-			locations[0] = locations[1]
-			locations[1] = loc
+			cliConnections[0], cliConnections[1] = cliConnections[1], cliConnections[0]
+			locations[0], locations[1] = locations[1], locations[0]
 		}
 		dest = *locations[1]
 	case len(locations) == 1:
diff --git a/cmd/podman/pods/create.go b/cmd/podman/pods/create.go
index b45ed0d39..891ff2e3c 100644
--- a/cmd/podman/pods/create.go
+++ b/cmd/podman/pods/create.go
@@ -224,7 +224,8 @@ func create(cmd *cobra.Command, args []string) error {
 	}
 	sort.Ints(vals)
 	for ind, core := range vals {
-		if core > int(cpuSet) {
+		switch {
+		case core > int(cpuSet):
 			if copy == "" {
 				copy = "0-" + strconv.Itoa(int(cpuSet))
 				infraOptions.CPUSetCPUs = copy
@@ -233,9 +234,9 @@ func create(cmd *cobra.Command, args []string) error {
 				infraOptions.CPUSetCPUs = copy
 				break
 			}
-		} else if ind != 0 {
+		case ind != 0:
 			copy += "," + strconv.Itoa(core)
-		} else {
+		default:
 			copy = "" + strconv.Itoa(core)
 		}
 	}
diff --git a/cmd/podman/secrets/create.go b/cmd/podman/secrets/create.go
index 069e2a1dc..01ee3d256 100644
--- a/cmd/podman/secrets/create.go
+++ b/cmd/podman/secrets/create.go
@@ -62,13 +62,14 @@ func create(cmd *cobra.Command, args []string) error {
 	path := args[1]
 
 	var reader io.Reader
-	if env {
+	switch {
+	case env:
 		envValue := os.Getenv(path)
 		if envValue == "" {
 			return errors.Errorf("cannot create store secret data: environment variable %s is not set", path)
 		}
 		reader = strings.NewReader(envValue)
-	} else if path == "-" || path == "/dev/stdin" {
+	case path == "-" || path == "/dev/stdin":
 		stat, err := os.Stdin.Stat()
 		if err != nil {
 			return err
@@ -77,7 +78,7 @@ func create(cmd *cobra.Command, args []string) error {
 			return errors.New("if `-` is used, data must be passed into stdin")
 		}
 		reader = os.Stdin
-	} else {
+	default:
 		file, err := os.Open(path)
 		if err != nil {
 			return err
diff --git a/cmd/podman/system/migrate.go b/cmd/podman/system/migrate.go
index 5d7b31314..b2bca9be0 100644
--- a/cmd/podman/system/migrate.go
+++ b/cmd/podman/system/migrate.go
@@ -69,6 +69,10 @@ func migrate(cmd *cobra.Command, args []string) {
 	err = engine.Migrate(registry.Context(), cmd.Flags(), registry.PodmanConfig(), migrateOptions)
 	if err != nil {
 		fmt.Println(err)
+
+		// FIXME change this to return the error like other commands
+		// defer will never run on os.Exit()
+		//nolint:gocritic
 		os.Exit(define.ExecErrorCodeGeneric)
 	}
 	os.Exit(0)
diff --git a/cmd/podman/system/renumber.go b/cmd/podman/system/renumber.go
index f24488822..e5a241a4f 100644
--- a/cmd/podman/system/renumber.go
+++ b/cmd/podman/system/renumber.go
@@ -56,6 +56,9 @@ func renumber(cmd *cobra.Command, args []string) {
 	err = engine.Renumber(registry.Context(), cmd.Flags(), registry.PodmanConfig())
 	if err != nil {
 		fmt.Println(err)
+		// FIXME change this to return the error like other commands
+		// defer will never run on os.Exit()
+		//nolint:gocritic
 		os.Exit(define.ExecErrorCodeGeneric)
 	}
 	os.Exit(0)
diff --git a/cmd/podman/system/reset.go b/cmd/podman/system/reset.go
index e8cf127b7..03783170f 100644
--- a/cmd/podman/system/reset.go
+++ b/cmd/podman/system/reset.go
@@ -95,6 +95,9 @@ func reset(cmd *cobra.Command, args []string) {
 
 	if err := engine.Reset(registry.Context()); err != nil {
 		logrus.Error(err)
+		// FIXME change this to return the error like other commands
+		// defer will never run on os.Exit()
+		//nolint:gocritic
 		os.Exit(define.ExecErrorCodeGeneric)
 	}
 	os.Exit(0)
diff --git a/cmd/podman/utils/alias.go b/cmd/podman/utils/alias.go
index 4d5b625d0..b37d0f714 100644
--- a/cmd/podman/utils/alias.go
+++ b/cmd/podman/utils/alias.go
@@ -37,8 +37,7 @@ func AliasFlags(f *pflag.FlagSet, name string) pflag.NormalizedName {
 
 // TimeoutAliasFlags is a function to handle backwards compatibility with old timeout flags
 func TimeoutAliasFlags(f *pflag.FlagSet, name string) pflag.NormalizedName {
-	switch name {
-	case "timeout":
+	if name == "timeout" {
 		name = "time"
 	}
 	return pflag.NormalizedName(name)