feat(switch): add command to quickly switch between worktrees

cmd/root.go

@@ -85,6 +85,7 @@ func init() {
 	rootCmd.AddCommand(configCmd)
 	rootCmd.AddCommand(upCmd)
 	rootCmd.AddCommand(downCmd)
+	rootCmd.AddCommand(switchCmd)
 }
 
 // Execute runs the root command

cmd/switch.go

@@ -0,0 +1,258 @@
+package cmd
+
+import (
+	"bufio"
+	"fmt"
+	"os"
+	"path/filepath"
+	"sort"
+	"strconv"
+	"strings"
+
+	"github.com/javoire/stackinator/internal/git"
+	"github.com/javoire/stackinator/internal/stack"
+	"github.com/spf13/cobra"
+)
+
+var switchInit bool
+var switchInstall bool
+
+var switchCmd = &cobra.Command{
+	Use:   "switch [branch]",
+	Short: "Print cd command to switch to a branch's worktree",
+	Long: `Print a cd command to switch to the worktree for a given branch.
+
+With no arguments, shows an interactive picker of all worktrees.
+Use --init to output a shell function that wraps this command with actual cd.
+Use --install to add the shell function to your shell config.`,
+	Example: `  # Switch to a branch's worktree
+  eval "$(stack switch my-feature)"
+
+  # Interactive picker
+  eval "$(stack switch)"
+
+  # Output shell function
+  stack switch --init
+
+  # Install shell function to ~/.zshrc
+  stack switch --install`,
+	Annotations: map[string]string{"skipGitValidation": "true"},
+	Args:        cobra.MaximumNArgs(1),
+	Run: func(cmd *cobra.Command, args []string) {
+		if switchInit {
+			runSwitchInit()
+			return
+		}
+
+		if switchInstall {
+			if err := runSwitchInstall(); err != nil {
+				fmt.Fprintf(os.Stderr, "Error: %v\n", err)
+				os.Exit(1)
+			}
+			return
+		}
+
+		// Run root's PersistentPreRun for git validation
+		rootCmd.PersistentPreRun(cmd, args)
+
+		gitClient := git.NewGitClient()
+
+		var err error
+		if len(args) == 1 {
+			err = runSwitch(gitClient, args[0])
+		} else {
+			err = runSwitchInteractive(gitClient)
+		}
+		if err != nil {
+			fmt.Fprintf(os.Stderr, "Error: %v\n", err)
+			os.Exit(1)
+		}
+	},
+}
+
+func init() {
+	switchCmd.Flags().BoolVar(&switchInit, "init", false, "Output shell function for wrapping switch with cd")
+	switchCmd.Flags().BoolVar(&switchInstall, "install", false, "Add shell function to shell config")
+}
+
+func runSwitchInit() {
+	fmt.Print(`ss() {
+  local dir
+  dir=$(command stack switch "$@" 2>/dev/null)
+  if [ $? -eq 0 ] && [ -n "$dir" ]; then
+    eval "$dir"
+  else
+    command stack switch "$@"
+  fi
+}
+`)
+}
+
+func runSwitch(gitClient git.GitClient, branchName string) error {
+	path, err := resolveWorktreePath(gitClient, branchName)
+	if err != nil {
+		return err
+	}
+	fmt.Printf("cd '%s'\n", path)
+	return nil
+}
+
+func resolveWorktreePath(gitClient git.GitClient, branchName string) (string, error) {
+	// Check if it's the base branch
+	baseBranch := stack.GetBaseBranch(gitClient)
+	if branchName == baseBranch {
+		repoRoot, err := gitClient.GetRepoRoot()
+		if err != nil {
+			return "", fmt.Errorf("failed to get repo root: %w", err)
+		}
+		return repoRoot, nil
+	}
+
+	// Look up in worktree branches
+	worktreeBranches, err := gitClient.GetWorktreeBranches()
+	if err != nil {
+		return "", fmt.Errorf("failed to get worktree branches: %w", err)
+	}
+
+	if path, ok := worktreeBranches[branchName]; ok {
+		return path, nil
+	}
+
+	return "", fmt.Errorf("no worktree found for branch %s", branchName)
+}
+
+func runSwitchInteractive(gitClient git.GitClient) error {
+	worktreesBaseDir, err := getWorktreesBaseDir(gitClient)
+	if err != nil {
+		return err
+	}
+
+	repoName, err := gitClient.GetRepoName()
+	if err != nil {
+		return fmt.Errorf("failed to get repo name: %w", err)
+	}
+
+	worktreesDir := filepath.Join(worktreesBaseDir, repoName)
+
+	// Get worktree branches
+	worktreeBranches, err := gitClient.GetWorktreeBranches()
+	if err != nil {
+		return fmt.Errorf("failed to get worktree branches: %w", err)
+	}
+
+	// Get current worktree path for marking
+	currentPath, _ := gitClient.GetCurrentWorktreePath()
+
+	// Collect options: worktrees in the worktrees dir + main repo
+	type option struct {
+		branch string
+		path   string
+	}
+	var options []option
+
+	// Add main repo
+	baseBranch := stack.GetBaseBranch(gitClient)
+	repoRoot, err := gitClient.GetRepoRoot()
+	if err != nil {
+		return fmt.Errorf("failed to get repo root: %w", err)
+	}
+	options = append(options, option{branch: baseBranch, path: repoRoot})
+
+	// Add worktrees filtered to this repo's worktrees dir
+	var sortedBranches []string
+	for branch, path := range worktreeBranches {
+		if pathWithinDir(path, worktreesDir) {
+			sortedBranches = append(sortedBranches, branch)
+		}
+	}
+	sort.Strings(sortedBranches)
+	for _, branch := range sortedBranches {
+		options = append(options, option{branch: branch, path: worktreeBranches[branch]})
+	}
+
+	if len(options) <= 1 {
+		return fmt.Errorf("no worktrees found")
+	}
+
+	// Display options
+	fmt.Fprintf(os.Stderr, "Select a worktree:\n\n")
+	for i, opt := range options {
+		marker := " "
+		if opt.path == currentPath {
+			marker = "*"
+		}
+		fmt.Fprintf(os.Stderr, "  %s %d) %s\n", marker, i+1, opt.branch)
+		fmt.Fprintf(os.Stderr, "       %s\n", opt.path)
+	}
+	fmt.Fprintf(os.Stderr, "\n> ")
+
+	// Read selection
+	reader := bufio.NewReader(os.Stdin)
+	input, err := reader.ReadString('\n')
+	if err != nil {
+		return fmt.Errorf("failed to read input: %w", err)
+	}
+	input = strings.TrimSpace(input)
+
+	idx, err := strconv.Atoi(input)
+	if err != nil || idx < 1 || idx > len(options) {
+		return fmt.Errorf("invalid selection: %s", input)
+	}
+
+	selected := options[idx-1]
+	fmt.Printf("cd '%s'\n", selected.path)
+	return nil
+}
+
+func runSwitchInstall() error {
+	homeDir, err := getHomeDir()
+	if err != nil {
+		return err
+	}
+
+	// Detect shell
+	shell := os.Getenv("SHELL")
+	var rcFile string
+	switch {
+	case strings.HasSuffix(shell, "/bash"):
+		rcFile = filepath.Join(homeDir, ".bashrc")
+	default:
+		// Default to zsh
+		rcFile = filepath.Join(homeDir, ".zshrc")
+	}
+
+	// Read existing file
+	content, err := os.ReadFile(rcFile)
+	if err != nil && !os.IsNotExist(err) {
+		return fmt.Errorf("failed to read %s: %w", rcFile, err)
+	}
+
+	// Check if already installed
+	initLine := `eval "$(stack switch --init)"`
+	if strings.Contains(string(content), initLine) {
+		fmt.Fprintf(os.Stderr, "Already installed in %s\n", rcFile)
+		return nil
+	}
+
+	// Dry-run: show what would be appended
+	if dryRun {
+		fmt.Fprintf(os.Stderr, "Would append to %s:\n%s\n", rcFile, initLine)
+		return nil
+	}
+
+	// Append
+	f, err := os.OpenFile(rcFile, os.O_APPEND|os.O_CREATE|os.O_WRONLY, 0644)
+	if err != nil {
+		return fmt.Errorf("failed to open %s: %w", rcFile, err)
+	}
+	defer f.Close()
+
+	entry := fmt.Sprintf("\n# stackinator: ss() function for quick worktree switching\n%s\n", initLine)
+	if _, err := f.WriteString(entry); err != nil {
+		return fmt.Errorf("failed to write to %s: %w", rcFile, err)
+	}
+
+	fmt.Fprintf(os.Stderr, "Added ss() function to %s\n", rcFile)
+	fmt.Fprintf(os.Stderr, "Run 'source %s' or start a new shell to use it.\n", rcFile)
+	return nil
+}

cmd/switch_test.go

@@ -0,0 +1,101 @@
+package cmd
+
+import (
+	"bytes"
+	"io"
+	"os"
+	"testing"
+
+	"github.com/javoire/stackinator/internal/testutil"
+	"github.com/stretchr/testify/assert"
+)
+
+func TestRunSwitch(t *testing.T) {
+	testutil.SetupTest()
+	defer testutil.TeardownTest()
+
+	t.Run("resolves worktree branch to path", func(t *testing.T) {
+		mockGit := new(testutil.MockGitClient)
+
+		mockGit.On("GetConfig", "stack.baseBranch").Return("")
+		mockGit.On("GetDefaultBranch").Return("main")
+		mockGit.On("GetWorktreeBranches").Return(map[string]string{
+			"feature-a": "/home/user/.stack/worktrees/repo/feature-a",
+			"feature-b": "/home/user/.stack/worktrees/repo/feature-b",
+		}, nil)
+
+		// Capture stdout
+		old := os.Stdout
+		r, w, _ := os.Pipe()
+		os.Stdout = w
+
+		err := runSwitch(mockGit, "feature-a")
+
+		w.Close()
+		os.Stdout = old
+		var buf bytes.Buffer
+		io.Copy(&buf, r)
+
+		assert.NoError(t, err)
+		assert.Equal(t, "cd '/home/user/.stack/worktrees/repo/feature-a'\n", buf.String())
+		mockGit.AssertExpectations(t)
+	})
+
+	t.Run("resolves base branch to repo root", func(t *testing.T) {
+		mockGit := new(testutil.MockGitClient)
+
+		mockGit.On("GetConfig", "stack.baseBranch").Return("")
+		mockGit.On("GetDefaultBranch").Return("main")
+		mockGit.On("GetRepoRoot").Return("/home/user/code/repo", nil)
+
+		old := os.Stdout
+		r, w, _ := os.Pipe()
+		os.Stdout = w
+
+		err := runSwitch(mockGit, "main")
+
+		w.Close()
+		os.Stdout = old
+		var buf bytes.Buffer
+		io.Copy(&buf, r)
+
+		assert.NoError(t, err)
+		assert.Equal(t, "cd '/home/user/code/repo'\n", buf.String())
+		mockGit.AssertExpectations(t)
+	})
+
+	t.Run("errors for unknown branch", func(t *testing.T) {
+		mockGit := new(testutil.MockGitClient)
+
+		mockGit.On("GetConfig", "stack.baseBranch").Return("")
+		mockGit.On("GetDefaultBranch").Return("main")
+		mockGit.On("GetWorktreeBranches").Return(map[string]string{}, nil)
+
+		err := runSwitch(mockGit, "nonexistent")
+
+		assert.Error(t, err)
+		assert.Contains(t, err.Error(), "no worktree found")
+		mockGit.AssertExpectations(t)
+	})
+}
+
+func TestRunSwitchInit(t *testing.T) {
+	testutil.SetupTest()
+	defer testutil.TeardownTest()
+
+	old := os.Stdout
+	r, w, _ := os.Pipe()
+	os.Stdout = w
+
+	runSwitchInit()
+
+	w.Close()
+	os.Stdout = old
+	var buf bytes.Buffer
+	io.Copy(&buf, r)
+
+	output := buf.String()
+	assert.Contains(t, output, "ss()")
+	assert.Contains(t, output, "command stack switch")
+	assert.Contains(t, output, "eval")
+}

decision-log.md

@@ -2,6 +2,14 @@
 
 Architectural and design decisions for Stackinator.
 
+## 2026-03-10 — Add `stack switch` command for worktree navigation
+
+**Decision**: Add a `switch` command that outputs `cd <path>` for quick worktree navigation.
+
+**Context**: Users work across multiple worktrees and the main repo. `stack worktree --list` shows paths but requires manual copy-paste. A faster way to jump between worktrees was needed.
+
+**Resolution**: `stack switch <branch>` resolves a branch to its worktree path and prints `cd <path>`. No-args mode shows an interactive picker. `--init` outputs a shell function `ss()` that wraps the command with actual `cd`. `--install` appends the init line to the shell config. The command reuses existing helpers (`getWorktreesBaseDir`, `pathWithinDir`, `GetWorktreeBranches`).
+
 ## 2026-03-06 — Add merged-parent detection to `stack status`
 
 **Decision**: Add merged-parent detection to `stack status`.