Polish codebase: fix panics, check errors, reduce duplication

Clean code analysis and refactoring across 31 files:

- Add bounds checking to prevent panics on unexpected system command output
- Check ignored errors from json.Unmarshal, os.WriteFile, cobra Execute()
- Extract shared utilities: pkg/jsonutil.Print, pkg/run.CaptureClean
- Unify component registry into single source of truth
- Consolidate duplicate code in link, spotify auth, and slack packages
- Replace os.Exit in cache.Log with bool return for testability
- Remove unused types, fix byte-vs-rune slicing, use const where appropriate

Co-Authored-By: Claude <noreply@anthropic.com>

Author: drn

cli/commands/docker.go

@@ -11,7 +11,7 @@ var cmdDocker = &cobra.Command{
 	Aliases: []string{"dock"},
 	Short:   "Docker command aliases",
 	Run: func(cmd *cobra.Command, _ []string) {
-		cmd.Help()
+		_ = cmd.Help()
 	},
 }
 

cli/commands/install.go

@@ -10,45 +10,21 @@ import (
 	"github.com/spf13/cobra"
 )
 
-type component struct {
-	Name        string
-	Description string
-	Alias       string
-}
-
-var components = []component{
-	{"bin", "Installs ~/bin/* commands", ""},
-	{"git", "Installs git extensions", ""},
-	{"home", "Installs ~/.* config files", ""},
-	{"zsh", "Installs zsh config files", ""},
-	{"fonts", "Installs fonts", ""},
-	{"homebrew", "Installs Homebrew dependencies", "brew"},
-	{"npm", "Installs npm packages", ""},
-	{"languages", "Installs asdf & languages", ""},
-	{"vim", "Installs vim config", ""},
-	{"hammerspoon", "Installs hammerspoon configuration", "hs"},
-	{"osx", "Installs OSX configuration", ""},
-	{"agents", "Installs agent skills (Claude Code + Codex)", ""},
-}
-
-func componentNames() []string {
-	names := make([]string, len(components))
-	for i, c := range components {
-		names[i] = c.Name
-	}
-	return names
-}
-
 var cmdInstall = &cobra.Command{
 	Use:   "install",
 	Short: "Installs configuration",
 	Run: func(cmd *cobra.Command, args []string) {
 		if len(args) > 0 {
-			cmd.Help()
+			_ = cmd.Help()
 			os.Exit(1)
 		}
 
-		items := append([]string{"all"}, componentNames()...)
+		components := install.Components()
+		names := make([]string, len(components))
+		for i, c := range components {
+			names[i] = c.Name
+		}
+		items := append([]string{"all"}, names...)
 
 		prompt := promptui.Select{
 			Label: "Select component to install",
@@ -79,7 +55,7 @@ func init() {
 		},
 	)
 
-	for _, c := range components {
+	for _, c := range install.Components() {
 		var aliases []string
 		if c.Alias != "" {
 			aliases = []string{c.Alias}
@@ -105,7 +81,7 @@ func installAll() {
 		os.Exit(1)
 	}
 
-	for _, name := range componentNames() {
-		install.Call(name)
+	for _, c := range install.Components() {
+		install.Call(c.Name)
 	}
 }

cli/commands/install/root.go

@@ -7,24 +7,40 @@ import (
 	"github.com/drn/dots/pkg/run"
 )
 
+// Component describes an installable component
+type Component struct {
+	Name        string
+	Description string
+	Alias       string
+	Fn          func()
+}
+
+// Components returns the ordered list of installable components.
+// This is the single source of truth for the component registry.
+func Components() []Component {
+	return []Component{
+		{"bin", "Installs ~/bin/* commands", "", Bin},
+		{"git", "Installs git extensions", "", Git},
+		{"home", "Installs ~/.* config files", "", Home},
+		{"zsh", "Installs zsh config files", "", Zsh},
+		{"fonts", "Installs fonts", "", Fonts},
+		{"homebrew", "Installs Homebrew dependencies", "brew", Homebrew},
+		{"npm", "Installs npm packages", "", Npm},
+		{"languages", "Installs asdf & languages", "", Languages},
+		{"vim", "Installs vim config", "", Vim},
+		{"hammerspoon", "Installs hammerspoon configuration", "hs", Hammerspoon},
+		{"osx", "Installs OSX configuration", "", Osx},
+		{"agents", "Installs agent skills (Claude Code + Codex)", "", Agents},
+	}
+}
+
 // Call - Call install command by name
 func Call(command string) {
-	installers := map[string]func(){
-		"agents":      Agents,
-		"bin":         Bin,
-		"fonts":       Fonts,
-		"git":         Git,
-		"hammerspoon": Hammerspoon,
-		"home":        Home,
-		"homebrew":    Homebrew,
-		"languages":   Languages,
-		"npm":         Npm,
-		"osx":         Osx,
-		"vim":         Vim,
-		"zsh":         Zsh,
-	}
-	if fn, ok := installers[command]; ok {
-		fn()
+	for _, c := range Components() {
+		if c.Name == command {
+			c.Fn()
+			return
+		}
 	}
 }
 

cli/commands/install/vim.go

@@ -67,7 +67,7 @@ func vimUpdatePlug() {
 func vimUpdatePlugins() {
 	log.Info("Updating vim plugins:")
 	tempPath := "/tmp/vim-update-result"
-	os.Remove(tempPath)
+	_ = os.Remove(tempPath)
 	run.Silent(
 		"nvim -c \"%s\"",
 		strings.Join(

cli/commands/root.go

@@ -12,7 +12,7 @@ var root = &cobra.Command{
 	Use:   "dots",
 	Short: "The dots CLI manages your development environment dependencies",
 	Run: func(cmd *cobra.Command, _ []string) {
-		cmd.Help()
+		_ = cmd.Help()
 	},
 }
 

cli/commands/spinner.go

@@ -14,7 +14,7 @@ var cmdSpinner = &cobra.Command{
 	Use:   "spinner",
 	Short: "Runs simple CLI spinners",
 	Run: func(cmd *cobra.Command, _ []string) {
-		cmd.Help()
+		_ = cmd.Help()
 	},
 }
 

cli/config/root.go

@@ -132,7 +132,9 @@ func save(cfg *ini.File) {
 		log.Warning("Failed to create config directory: %s", err.Error())
 		return
 	}
-	cfg.SaveTo(configPath())
+	if err := cfg.SaveTo(configPath()); err != nil {
+		log.Warning("Failed to save config: %s", err.Error())
+	}
 }
 
 func config() *ini.File {

cli/git/root.go

@@ -102,8 +102,8 @@ func Create(branch string) bool {
 }
 
 // ResetHard - Hard resets to the specified address
-func ResetHard(address string) {
-	run.Verbose("git reset --hard %s", address)
+func ResetHard(address string) bool {
+	return run.Verbose("git reset --hard %s", address) == nil
 }
 
 // Delete - Deletes the specified branch

cli/link/root.go

@@ -10,30 +10,18 @@ import (
 
 // Soft - Creates a soft link between input from and to arguments
 func Soft(from string, to string) {
-	log.Info("Soft link: '%s' -> '%s'", path.Pretty(to), path.Pretty(from))
-
-	removeExisting(to)
-
-	// create soft link
-	err := os.Symlink(from, to)
-
-	// log errors
-	if err != nil {
-		log.Error(err.Error())
-	}
+	create("Soft", from, to, os.Symlink)
 }
 
 // Hard - Creates a hard link between input from and to arguments
 func Hard(from string, to string) {
-	log.Info("Hard link: '%s' -> '%s'", path.Pretty(to), path.Pretty(from))
+	create("Hard", from, to, os.Link)
+}
 
+func create(label, from, to string, linkFn func(string, string) error) {
+	log.Info("%s link: '%s' -> '%s'", label, path.Pretty(to), path.Pretty(from))
 	removeExisting(to)
-
-	// create hard link
-	err := os.Link(from, to)
-
-	// log errors
-	if err != nil {
+	if err := linkFn(from, to); err != nil {
 		log.Error(err.Error())
 	}
 }

cmd/battery-percent/root.go

@@ -9,11 +9,19 @@ import (
 )
 
 func main() {
-	info := run.Capture("pmset -g ps")
-	info = strings.Split(info, "\n")[1]
-	// extract percent from pmset metadata
-	percent := strings.Fields(info)[2]
-	// remove trailing ;
-	percent = percent[:len(percent)-1]
+	lines := strings.Split(run.Capture("pmset -g ps"), "\n")
+	if len(lines) < 2 {
+		fmt.Println("0%")
+		return
+	}
+	fields := strings.Fields(lines[1])
+	if len(fields) < 3 {
+		fmt.Println("0%")
+		return
+	}
+	percent := fields[2]
+	if len(percent) > 0 {
+		percent = strings.TrimRight(percent, ";")
+	}
 	fmt.Println(percent)
 }