chore(ci): be golangci-lint compatible

cmd/root.go

@@ -19,16 +19,18 @@ func Execute(version string) error {
 		DisableFlagsInUseLine: true,
 		ValidArgs:             []string{"bash", "zsh", "fish", "powershell"},
 		Args:                  cobra.MatchAll(cobra.ExactArgs(1)),
-		Run: func(cmd *cobra.Command, args []string) {
+		RunE: func(cmd *cobra.Command, args []string) error {
 			switch args[0] {
 			case "bash":
-				cmd.Root().GenBashCompletion(os.Stdout)
+				return cmd.Root().GenBashCompletion(os.Stdout)
 			case "zsh":
-				cmd.Root().GenZshCompletion(os.Stdout)
+				return cmd.Root().GenZshCompletion(os.Stdout)
 			case "fish":
-				cmd.Root().GenFishCompletion(os.Stdout, true)
+				return cmd.Root().GenFishCompletion(os.Stdout, true)
 			case "powershell":
-				cmd.Root().GenPowerShellCompletionWithDesc(os.Stdout)
+				return cmd.Root().GenPowerShellCompletionWithDesc(os.Stdout)
+			default:
+				return fmt.Errorf("unknown shell: %v", args[0])
 			}
 		},
 	}
@@ -53,17 +55,17 @@ dcmerge docker-compose.yml https://git.example.local/user/repo/docker-compose.ym
 func run(cmd *cobra.Command, args []string) error {
 	mergeExisting, err := cmd.Flags().GetBool("existing-win")
 	if err != nil {
-		return fmt.Errorf("Failed to parse flag last-win: %s", err)
+		return fmt.Errorf("failed to parse flag last-win: %s", err)
 	}
 
 	mergeLastWin, err := cmd.Flags().GetBool("last-win")
 	if err != nil {
-		return fmt.Errorf("Failed to parse flag last-win: %s", err)
+		return fmt.Errorf("failed to parse flag last-win: %s", err)
 	}
 
 	outputFile, err := cmd.Flags().GetString("output-file")
 	if err != nil {
-		return fmt.Errorf("Failed to parse flag output-file: %s", err)
+		return fmt.Errorf("failed to parse flag output-file: %s", err)
 	}
 
 	dockerComposeConfig := dockerCompose.NewConfig()
@@ -76,7 +78,7 @@ func run(cmd *cobra.Command, args []string) error {
 	for _, config := range dockerComposeConfigs {
 		switch {
 		case mergeExisting && mergeLastWin:
-			return fmt.Errorf("Neither --first-win or --last-win can be specified - not booth.")
+			return fmt.Errorf("neither --first-win or --last-win can be specified - not booth")
 		case mergeExisting && !mergeLastWin:
 			dockerComposeConfig.MergeExistingWin(config)
 		case !mergeExisting && mergeLastWin:
@@ -97,7 +99,7 @@ func run(cmd *cobra.Command, args []string) error {
 		if err != nil {
 			return err
 		}
-		defer f.Close()
+		defer func() { _ = f.Close() }()
 
 		yamlEncoder := yaml.NewEncoder(f)
 		yamlEncoder.SetIndent(2)

pkg/domain/dockerCompose/config.go

@@ -1305,8 +1305,8 @@ func (sdoc *DependsOnContainer) Equal(equalable Equalable) bool {
 
 // MarshalYAML implements the MarshalYAML interface to customize the behavior when being marshaled into a YAML document.
 func (sdoc *DependsOnContainer) MarshalYAML() (interface{}, error) {
-	var foundAnotherCondition bool = false
-	var dependencyNames []string
+	var foundAnotherCondition = false
+	var dependencyNames = make([]string, 0)
 
 	for dependencyName, dependencyDefinition := range sdoc.DependsOn {
 		if dependencyDefinition.Condition == ServiceDependsOnConditionServiceStarted {

pkg/domain/dockerCompose/equalable.go

@@ -55,8 +55,8 @@ func EqualStringMap[R Equalable](mapA, mapB map[string]R) bool {
 
 // ExistsInMap returns true if object of type any exists under the passed name.
 func ExistsInMap[T any](m map[string]T, name string) bool {
-	switch {
-	case m == nil:
+	switch m {
+	case nil:
 		return false
 	default:
 		_, present := m[name]

pkg/fetcher/fetcher.go

@@ -20,15 +20,15 @@ func Fetch(urls ...string) ([]*dockerCompose.Config, error) {
 			return nil, err
 		}
 
-		switch {
-		case dockerComposeURL.Scheme == "http" || dockerComposeURL.Scheme == "https":
+		switch dockerComposeURL.Scheme {
+		case "http", "https":
 			dockerComposeConfig, err := getDockerComposeViaHTTP(dockerComposeURL.String())
 			if err != nil {
 				return nil, err
 			}
 
 			dockerComposeConfigs = append(dockerComposeConfigs, dockerComposeConfig)
-		case dockerComposeURL.Scheme == "file":
+		case "file":
 			fallthrough
 		default:
 			dockerComposeConfig, err := readDockerComposeFromFile(dockerComposeURL.Path)
@@ -43,7 +43,7 @@ func Fetch(urls ...string) ([]*dockerCompose.Config, error) {
 	return dockerComposeConfigs, nil
 }
 
-var ErrorPathIsDir error = errors.New("Path is a directory")
+var ErrorPathIsDir error = errors.New("path is a directory")
 
 func getDockerComposeViaHTTP(url string) (*dockerCompose.Config, error) {
 	req, err := http.NewRequest(http.MethodGet, url, nil)
@@ -55,10 +55,10 @@ func getDockerComposeViaHTTP(url string) (*dockerCompose.Config, error) {
 	if err != nil {
 		return nil, err
 	}
-	defer resp.Body.Close()
+	defer func() { _ = resp.Body.Close() }()
 
 	if resp.StatusCode != http.StatusOK {
-		return nil, fmt.Errorf("Received unexpected HTTP-Statuscode %v", resp.StatusCode)
+		return nil, fmt.Errorf("received unexpected HTTP-Statuscode %v", resp.StatusCode)
 	}
 
 	dockerCompose := dockerCompose.NewConfig()
@@ -85,7 +85,7 @@ func readDockerComposeFromFile(name string) (*dockerCompose.Config, error) {
 	if err != nil {
 		return nil, err
 	}
-	defer file.Close()
+	defer func() { _ = file.Close() }()
 
 	dockerCompose := dockerCompose.NewConfig()