feat: add force flag to stack branch rename

cmd/av/pr.go

@@ -5,13 +5,12 @@ import (
 )
 
 var prCmd = &cobra.Command{
-	Use: "pr",
+	Use:   "pr",
 	Short: "manage pull requests",
 }
 
 func init() {
 	prCmd.AddCommand(
 		prCreateCmd,
-
 	)
 }

cmd/av/stack_branch.go

@@ -15,8 +15,11 @@ var stackBranchFlags struct {
 	Parent string
 	// If true, rename the current branch ("move" in Git parlance, though we
 	// avoid that language here since we're not changing the branch's position
-	// within the stack).
+	// within the stack). The branch can only be renamed if a pull request does
+	// not exist.
 	Rename bool
+	// If true, rename the current branch even if a pull request exists.
+	Force bool
 }
 var stackBranchCmd = &cobra.Command{
 	Use:   "branch [flags] <branch-name>",
@@ -46,7 +49,7 @@ internal tracking metadata that defines the order of branches within a stack.`,
 		}
 
 		if stackBranchFlags.Rename {
-			return stackBranchMove(repo, db, branchName)
+			return stackBranchMove(repo, db, branchName, stackBranchFlags.Force)
 		}
 
 		tx := db.WriteTx()
@@ -159,12 +162,15 @@ func init() {
 	// See the comment on stackBranchFlags.Rename.
 	stackBranchCmd.Flags().
 		BoolVarP(&stackBranchFlags.Rename, "rename", "m", false, "rename the current branch")
+	stackBranchCmd.Flags().
+		BoolVar(&stackBranchFlags.Force, "force", false, "force rename the current branch")
 }
 
 func stackBranchMove(
 	repo *git.Repo,
 	db meta.DB,
 	newBranch string,
+	force bool,
 ) (reterr error) {
 	oldBranch, err := repo.CurrentBranchName()
 	if err != nil {
@@ -193,9 +199,18 @@ func stackBranchMove(
 			Trunk: true,
 		}
 	}
+	currentMeta.PullRequest = nil
 	currentMeta.Name = newBranch
 	tx.SetBranch(currentMeta)
 
+	if !force {
+		if currentMeta.PullRequest != nil {
+			return errors.New(
+				"cannot rename branch because a pull request already exists (bypass with the `--force` flag, but this will require closing this pull request and opening a new one using `av pr create`)",
+			)
+		}
+	}
+
 	// Update all child branches to refer to the correct (renamed) parent.
 	children := meta.Children(tx, oldBranch)
 	for _, child := range children {

docs/av-stack-branch.1.md

@@ -6,7 +6,7 @@ av-stack-branch - Create or rename a branch in the stack
 
 # SYNOPSIS
 
-`av stack branch [-m | --rename] [--parent <parent_branch>] <branch-name>`
+`av stack branch [-m | --rename] [--force] [--parent <parent_branch>] <branch-name>`
 
 # DESCRIPTION
 
@@ -25,4 +25,7 @@ internal tracking metadata that defines the order of branches within a stack.
 
 `-m, --rename`
 : Rename the current branch to the provided `<branch_name>` instead of
-  creating a new one.
+  creating a new one, only if a pull request does not exist.
+
+`--force`
+: Force rename the branch, even if a pull request exists.