feat: consolidate reparent into parent command

cmd/parent.go

@@ -5,30 +5,54 @@ import (
 	"os"
 
 	"github.com/javoire/stackinator/internal/git"
+	"github.com/javoire/stackinator/internal/github"
 	"github.com/javoire/stackinator/internal/ui"
 	"github.com/spf13/cobra"
 )
 
 var parentCmd = &cobra.Command{
-	Use:   "parent",
-	Short: "Show the parent of the current branch",
-	Long: `Display the parent branch of the current branch in the stack.
+	Use:   "parent [new-parent]",
+	Short: "Show or change the parent of the current branch",
+	Long: `Show or change the parent branch of the current branch in the stack.
 
-If the current branch has no parent set, it will show that the branch
-is not part of a stack.`,
+Without arguments, displays the current parent branch.
+
+With a branch argument, changes the parent to the specified branch. This updates
+the stack parent relationship in git config and, if a PR exists for the current
+branch, automatically updates the PR base to match the new parent.`,
 	Example: `  # Show parent of current branch
-  stack parent`,
+  stack parent
+
+  # Change current branch to be based on a different parent
+  stack parent feature-auth
+
+  # Preview what would happen
+  stack parent main --dry-run`,
+	Args: cobra.MaximumNArgs(1),
 	Run: func(cmd *cobra.Command, args []string) {
 		gitClient := git.NewGitClient()
 
-		if err := runParent(gitClient); err != nil {
-			fmt.Fprintf(os.Stderr, "Error: %v\n", err)
-			os.Exit(1)
+		if len(args) == 0 {
+			// Show parent
+			if err := runShowParent(gitClient); err != nil {
+				fmt.Fprintf(os.Stderr, "Error: %v\n", err)
+				os.Exit(1)
+			}
+		} else {
+			// Reparent
+			newParent := args[0]
+			repo := github.ParseRepoFromURL(gitClient.GetRemoteURL("origin"))
+			githubClient := github.NewGitHubClient(repo)
+
+			if err := runReparent(gitClient, githubClient, newParent); err != nil {
+				fmt.Fprintf(os.Stderr, "Error: %v\n", err)
+				os.Exit(1)
+			}
 		}
 	},
 }
 
-func runParent(gitClient git.GitClient) error {
+func runShowParent(gitClient git.GitClient) error {
 	// Get current branch
 	currentBranch, err := gitClient.GetCurrentBranch()
 	if err != nil {
@@ -47,3 +71,111 @@ func runParent(gitClient git.GitClient) error {
 	return nil
 }
 
+func runReparent(gitClient git.GitClient, githubClient github.GitHubClient, newParent string) error {
+	// Get current branch
+	currentBranch, err := gitClient.GetCurrentBranch()
+	if err != nil {
+		return fmt.Errorf("failed to get current branch: %w", err)
+	}
+
+	// Get current parent (may be empty if not in a stack)
+	currentParent := gitClient.GetConfig(fmt.Sprintf("branch.%s.stackparent", currentBranch))
+
+	// Check if new parent is the same as current parent
+	if currentParent != "" && newParent == currentParent {
+		fmt.Printf("Branch %s is already parented to %s\n", ui.Branch(currentBranch), ui.Branch(newParent))
+		return nil
+	}
+
+	// Verify new parent branch exists
+	if !gitClient.BranchExists(newParent) {
+		return fmt.Errorf("new parent branch %s does not exist", newParent)
+	}
+
+	// Check if this would create a cycle
+	if newParent == currentBranch {
+		return fmt.Errorf("cannot set branch as its own parent")
+	}
+
+	// Check if new parent is a descendant of current branch (would create cycle)
+	if isDescendant(gitClient, currentBranch, newParent) {
+		return fmt.Errorf("cannot reparent to %s: it is a descendant of %s (would create a cycle)", newParent, currentBranch)
+	}
+
+	// Print appropriate message based on whether we're adding to stack or reparenting
+	if currentParent == "" {
+		fmt.Printf("Adding %s to stack with parent %s\n", ui.Branch(currentBranch), ui.Branch(newParent))
+	} else {
+		fmt.Printf("Reparenting %s: %s -> %s\n", ui.Branch(currentBranch), ui.Branch(currentParent), ui.Branch(newParent))
+	}
+
+	// Update git config
+	configKey := fmt.Sprintf("branch.%s.stackparent", currentBranch)
+	if err := gitClient.SetConfig(configKey, newParent); err != nil {
+		return fmt.Errorf("failed to update parent config: %w", err)
+	}
+
+	// Check if there's a PR for this branch
+	pr, err := githubClient.GetPRForBranch(currentBranch)
+	if err != nil {
+		// Error fetching PR info, but config was updated successfully
+		fmt.Println(ui.Success(fmt.Sprintf("Updated parent to %s", ui.Branch(newParent))))
+		fmt.Printf("Warning: failed to check for PR: %v\n", err)
+		return nil
+	}
+
+	if pr != nil {
+		// PR exists, update its base
+		fmt.Printf("Updating PR #%d base: %s -> %s\n", pr.Number, ui.Branch(pr.Base), ui.Branch(newParent))
+
+		if err := githubClient.UpdatePRBase(pr.Number, newParent); err != nil {
+			// Config was updated but PR base update failed
+			fmt.Println(ui.Success(fmt.Sprintf("Updated parent to %s", ui.Branch(newParent))))
+			return fmt.Errorf("failed to update PR base: %w", err)
+		}
+
+		if !dryRun {
+			fmt.Println(ui.Success(fmt.Sprintf("Updated parent to %s", ui.Branch(newParent))))
+			fmt.Println(ui.Success(fmt.Sprintf("Updated PR #%d base to %s", pr.Number, ui.Branch(newParent))))
+		}
+	} else {
+		// No PR exists
+		if !dryRun {
+			fmt.Println(ui.Success(fmt.Sprintf("Updated parent to %s", ui.Branch(newParent))))
+			fmt.Println("  (no PR found for this branch)")
+		}
+	}
+
+	return nil
+}
+
+// isDescendant checks if possibleDescendant is a descendant of ancestor in the stack
+func isDescendant(gitClient git.GitClient, ancestor, possibleDescendant string) bool {
+	// Walk up from possibleDescendant to see if we reach ancestor
+	current := possibleDescendant
+	visited := make(map[string]bool)
+
+	for current != "" {
+		// Prevent infinite loops
+		if visited[current] {
+			return false
+		}
+		visited[current] = true
+
+		// Get parent of current
+		parent := gitClient.GetConfig(fmt.Sprintf("branch.%s.stackparent", current))
+		if parent == "" {
+			// Reached the top of the stack without finding ancestor
+			return false
+		}
+
+		if parent == ancestor {
+			// Found ancestor in the chain
+			return true
+		}
+
+		current = parent
+	}
+
+	return false
+}

cmd/root.go

@@ -76,7 +76,6 @@ func init() {
 	rootCmd.AddCommand(pruneCmd)
 	rootCmd.AddCommand(parentCmd)
 	rootCmd.AddCommand(renameCmd)
-	rootCmd.AddCommand(reparentCmd)
 	rootCmd.AddCommand(worktreeCmd)
 	rootCmd.AddCommand(configCmd)
 	rootCmd.AddCommand(upCmd)

docs/commands.md

@@ -55,12 +55,21 @@ Flags:
 
 - `--force`, `-f` - Use `--force` instead of `--force-with-lease` for push (bypasses safety checks)
 
-## `stack parent`
+## `stack parent [new-parent]`
 
-Display the parent branch of the current branch in the stack.
+Show or change the parent branch of the current branch in the stack.
+
+Without arguments, displays the current parent. With a branch argument, changes the parent to the specified branch and updates the PR base if a PR exists.
 
 ```bash
+# Show parent of current branch
 stack parent
+
+# Change current branch to be based on a different parent
+stack parent feature-auth
+
+# Preview what would happen
+stack parent main --dry-run
 ```
 
 ## `stack prune`
@@ -100,20 +109,6 @@ stack rename feature-improved-name
 stack rename feature-improved-name --dry-run
 ```
 
-## `stack reparent <new-parent>`
-
-Change the parent branch of the current branch in the stack.
-
-Updates the stack parent relationship and, if a PR exists, automatically updates the PR base to match the new parent.
-
-```bash
-# Change current branch to be based on a different parent
-stack reparent feature-auth
-
-# Preview what would happen
-stack reparent main --dry-run
-```
-
 ## `stack worktree <branch-name> [base-branch]`
 
 Create a git worktree in the configured worktrees directory for the specified branch.