Reduce cognitive complexity (#911)

## Summary

1. Reduce cognitive complexity to 30
2. remove unnecessary nolint comments
3. Correct some comments
4. Remove unused `IsSymlink()`

## How was it tested?

Build and test.

Author: hezhizhen

.golangci.yml

@@ -41,7 +41,7 @@ linters-settings:
       - name: bool-literal-in-expr
       - name: cognitive-complexity
         arguments:
-          - 36 # TODO: gradually reduce it
+          - 30 # TODO: gradually reduce it
       - name: datarace
       - name: duplicated-imports
       - name: early-return

internal/boxcli/featureflag/feature.go

@@ -14,7 +14,6 @@ type feature struct {
 
 var features = map[string]*feature{}
 
-// nolint:unparam
 func disabled(name string) *feature {
 	if features[name] == nil {
 		features[name] = &feature{name: name}
@@ -23,7 +22,6 @@ func disabled(name string) *feature {
 	return features[name]
 }
 
-// nolint:unparam
 func enabled(name string) *feature {
 	if features[name] == nil {
 		features[name] = &feature{name: name}

internal/boxcli/generate/devcontainer_util.go

@@ -33,7 +33,7 @@ type vscode struct {
 	Extensions []string `json:"extensions"`
 }
 
-// Creates a Dockerfile in path and writes devcontainerDockerfile.tmpl's content into it
+// CreateDockerfile creates a Dockerfile in path and writes devcontainerDockerfile.tmpl's content into it
 func CreateDockerfile(tmplFS embed.FS, path string) error {
 	// create dockerfile
 	file, err := os.Create(filepath.Join(path, "Dockerfile"))

internal/fileutil/fileutil.go

@@ -38,21 +38,6 @@ func IsFile(path string) bool {
 	return info.Mode().IsRegular()
 }
 
-// IsSymlink returns true if the path exists *and* it is a symlink.
-//
-// It does *not* traverse symbolic links, and returns true even if the symlink
-// is broken.
-//
-// This is a convenience function that coerces errors to false. If it cannot
-// read the path for any reason (including a permission error) it returns false.
-func IsSymlink(path string) bool {
-	info, err := os.Lstat(path)
-	if err != nil {
-		return false
-	}
-	return (info.Mode().Type() & os.ModeSymlink) == os.ModeSymlink
-}
-
 func Exists(path string) bool {
 	err := TryExists(path)
 	return err == nil

internal/impl/devbox.go

@@ -441,21 +441,21 @@ func (d *Devbox) saveCfg() error {
 }
 
 func (d *Devbox) Services() (services.Services, error) {
-	result := services.Services{}
 	pluginSvcs, err := plugin.GetServices(d.mergedPackages(), d.projectDir)
 	if err != nil {
-		return result, err
+		return nil, err
 	}
 
 	userSvcs := services.FromProcessComposeYaml(d.projectDir)
 
-	svcSet, err := lo.Assign(pluginSvcs, userSvcs), nil
-
+	svcSet := lo.Assign(pluginSvcs, userSvcs)
 	keys := make([]string, 0, len(svcSet))
 	for k := range svcSet {
 		keys = append(keys, k)
 	}
 	slices.Sort(keys)
+
+	result := services.Services{}
 	for _, k := range keys {
 		result[k] = svcSet[k]
 	}

internal/impl/shell.go

@@ -16,6 +16,7 @@ import (
 
 	"github.com/alessio/shellescape"
 	"github.com/pkg/errors"
+
 	"go.jetpack.io/devbox/internal/debug"
 	"go.jetpack.io/devbox/internal/nix"
 	"go.jetpack.io/devbox/internal/xdg"
@@ -40,12 +41,11 @@ const (
 	shPosix   name = "posix"
 )
 
-var ErrNoRecognizableShellFound = errors.New(
-	"SHELL in undefined, and couldn't find any common shells in PATH")
+var ErrNoRecognizableShellFound = errors.New("SHELL in undefined, and couldn't find any common shells in PATH")
 
 // TODO consider splitting this struct's functionality so that there is a simpler
 // `nix.Shell` that can produce a raw nix shell once again.
-//
+
 // DevboxShell configures a user's shell to run in Devbox. Its zero value is a
 // fallback shell that launches a regular Nix shell.
 type DevboxShell struct {
@@ -179,8 +179,7 @@ func WithHooksFilePath(hooksFilePath string) ShellOption {
 	}
 }
 
-// TODO: Consider removing this once plugins add env vars directly to binaries
-// via wrapper scripts.
+// TODO: Consider removing this once plugins add env vars directly to binaries via wrapper scripts.
 func WithEnvVariables(envVariables map[string]string) ShellOption {
 	return func(s *DevboxShell) {
 		s.env = envVariables

internal/services/config.go

@@ -7,28 +7,30 @@ import (
 
 	"github.com/f1bonacc1/process-compose/src/types"
 	"github.com/pkg/errors"
+
 	"go.jetpack.io/devbox/internal/cuecfg"
 )
 
 func FromProcessComposeYaml(projectDir string) Services {
 	// TODO need to handle if a filepath is passed in
-	if processComposeYaml := lookupProcessCompose(projectDir, ""); processComposeYaml != "" {
-		userSvcs, err := readProcessCompose(processComposeYaml)
-		if err != nil {
-			fmt.Fprintf(os.Stderr, "error reading process-compose.yaml: %s, skipping", err)
-			return nil
-		}
-		return userSvcs
+	processComposeYaml := lookupProcessCompose(projectDir, "")
+	if processComposeYaml == "" {
+		return nil
+	}
+	userSvcs, err := readProcessCompose(processComposeYaml)
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "error reading process-compose.yaml: %s, skipping", err)
+		return nil
 	}
-	return Services{}
+	return userSvcs
 }
 
 func readProcessCompose(path string) (Services, error) {
 	processCompose := &types.Project{}
 	services := Services{}
-	errors := errors.WithStack(cuecfg.ParseFile(path, processCompose))
-	if errors != nil {
-		return nil, errors
+	err := errors.WithStack(cuecfg.ParseFile(path, processCompose))
+	if err != nil {
+		return nil, err
 	}
 
 	for name := range processCompose.Processes {

internal/services/status.go

@@ -12,6 +12,7 @@ import (
 
 	"github.com/fsnotify/fsnotify"
 	"github.com/pkg/errors"
+
 	"go.jetpack.io/devbox/internal/cloud/envir"
 )
 
@@ -44,40 +45,42 @@ func ListenToChanges(ctx context.Context, opts *ListenerOpts) error {
 	}()
 
 	// Start listening for events.
-	go func() {
-		for {
-			select {
-			case event, ok := <-watcher.Events:
-				if !ok {
-					return
-				}
+	go listenToEvents(watcher, opts)
 
-				// mutagen sync changes show up as create events
-				if event.Has(fsnotify.Write) || event.Has(fsnotify.Create) {
-					status, err := readServiceStatus(event.Name)
-					if err != nil {
-						fmt.Fprintf(opts.Writer, "Error reading status file: %s\n", err)
-						continue
-					}
+	// We only want events for the specific host.
+	return errors.WithStack(watcher.Add(filepath.Join(cloudFilePath(opts.ProjectDir), opts.HostID)))
+}
 
-					status, saveChanges := opts.UpdateFunc(status)
-					if saveChanges {
-						if err := writeServiceStatusFile(event.Name, status); err != nil {
-							fmt.Fprintf(opts.Writer, "Error updating status file: %s\n", err)
-						}
-					}
+func listenToEvents(watcher *fsnotify.Watcher, opts *ListenerOpts) {
+	for {
+		select {
+		case event, ok := <-watcher.Events:
+			if !ok {
+				return
+			}
+
+			// mutagen sync changes show up as create events
+			if event.Has(fsnotify.Write) || event.Has(fsnotify.Create) {
+				status, err := readServiceStatus(event.Name)
+				if err != nil {
+					fmt.Fprintf(opts.Writer, "Error reading status file: %s\n", err)
+					continue
 				}
-			case err, ok := <-watcher.Errors:
-				if !ok {
-					return
+
+				status, saveChanges := opts.UpdateFunc(status)
+				if saveChanges {
+					if err := writeServiceStatusFile(event.Name, status); err != nil {
+						fmt.Fprintf(opts.Writer, "Error updating status file: %s\n", err)
+					}
 				}
-				fmt.Fprintf(opts.Writer, "error: %s\n", err)
 			}
+		case err, ok := <-watcher.Errors:
+			if !ok {
+				return
+			}
+			fmt.Fprintf(opts.Writer, "error: %s\n", err)
 		}
-	}()
-
-	// We only want events for the specific host.
-	return errors.WithStack(watcher.Add(filepath.Join(cloudFilePath(opts.ProjectDir), opts.HostID)))
+	}
 }
 
 func cloudFilePath(projectDir string) string {