feat(cmd): improve adopt command ergonomics

Change signature from 'adopt [branch] --parent <parent>' to
'adopt <parent> [--branch <branch>]'. The parent is now the
required positional argument, and the branch to adopt defaults
to the current branch.

This better matches the typical workflow where you're already
on the branch you want to adopt.

Author: boneskull

cmd/adopt.go

@@ -12,17 +12,19 @@ import (
 )
 
 var adoptCmd = &cobra.Command{
-	Use:   "adopt [branch]",
+	Use:   "adopt <parent>",
 	Short: "Start tracking an existing branch",
-	Long:  `Start tracking an existing branch by setting its parent.`,
-	Args:  cobra.MaximumNArgs(1),
-	RunE:  runAdopt,
+	Long: `Start tracking an existing branch by setting its parent.
+
+By default, adopts the current branch. Use --branch to specify a different branch.`,
+	Args: cobra.ExactArgs(1),
+	RunE: runAdopt,
 }
 
-var adoptParentFlag string
+var adoptBranchFlag string
 
 func init() {
-	adoptCmd.Flags().StringVar(&adoptParentFlag, "parent", "", "parent branch")
+	adoptCmd.Flags().StringVar(&adoptBranchFlag, "branch", "", "branch to adopt (default: current branch)")
 	rootCmd.AddCommand(adoptCmd)
 }
 
@@ -39,10 +41,13 @@ func runAdopt(cmd *cobra.Command, args []string) error {
 
 	g := git.New(cwd)
 
-	// Determine branch to adopt
+	// Parent is the required positional argument
+	parent := args[0]
+
+	// Determine branch to adopt (from flag or current branch)
 	var branchName string
-	if len(args) > 0 {
-		branchName = args[0]
+	if adoptBranchFlag != "" {
+		branchName = adoptBranchFlag
 	} else {
 		branchName, err = g.CurrentBranch()
 		if err != nil {
@@ -60,12 +65,6 @@ func runAdopt(cmd *cobra.Command, args []string) error {
 		return fmt.Errorf("branch %q is already tracked", branchName)
 	}
 
-	// Determine parent
-	parent := adoptParentFlag
-	if parent == "" {
-		return fmt.Errorf("--parent is required")
-	}
-
 	// Validate parent is trunk or tracked
 	trunk, err := cfg.GetTrunk()
 	if err != nil {

e2e/adopt_orphan_test.go

@@ -11,8 +11,8 @@ func TestAdoptExistingBranch(t *testing.T) {
 	env.Git("checkout", "-b", "external-branch")
 	env.CreateCommit("external work")
 
-	// Adopt it with explicit parent
-	env.MustRun("adopt", "external-branch", "--parent", "main")
+	// Adopt it (current branch with main as parent)
+	env.MustRun("adopt", "main")
 
 	env.AssertStackParent("external-branch", "main")
 }