feat: ez checkout auto-cd into worktree

When checking out a branch that lives in a worktree, ez now prints the
worktree path to stdout instead of attempting `git checkout` (which would
fail). The shell wrapper (from `ez shell-init`) intercepts this and
cd's into the worktree automatically.

- `ez checkout feat/auth` → cd's to .worktrees/feat-auth if it's there
- `ez checkout 42` → same, by PR number
- Interactive selector also works with worktrees
- Non-worktree branches still use regular git checkout
- Agents: `cd $(ez checkout feat/auth)` works without the shell wrapper

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: rohoswagger

CLAUDE.md

@@ -133,6 +133,7 @@ These features exist specifically to make ez useable by AI agents:
 | 0.1.16 | (skipped) |
 | 0.1.17 | `ez shell-init` — shell integration for auto-cd on worktree create/delete (zoxide pattern); remove redundant sync summary |
 | 0.1.18 | `ez setup` — one-command shell configuration (PATH + shell-init); first-run hint prompts users to run it; `ez setup --yes` for agents |
+| 0.1.19 | `ez checkout` auto-cd's into worktree if branch is checked out there; shell wrapper intercepts checkout for cd |
 
 ---
 

Cargo.lock

@@ -1,6 +1,6 @@
 [package]
 name = "ez-stack"
-version = "0.1.18"
+version = "0.1.19"
 edition = "2024"
 rust-version = "1.85"
 description = "A CLI tool for managing stacked PRs with GitHub"

Cargo.toml

@@ -1,29 +1,58 @@
 use anyhow::Result;
 use dialoguer::Select;
+use std::collections::HashMap;
 
 use crate::git;
 use crate::github;
 use crate::stack::StackState;
 use crate::ui;
 
+/// Build a map of branch name → worktree path for branches in worktrees.
+fn worktree_map() -> HashMap<String, String> {
+    git::worktree_list()
+        .unwrap_or_default()
+        .into_iter()
+        .filter(|wt| wt.path.contains("/.worktrees/"))
+        .filter_map(|wt| wt.branch.map(|b| (b, wt.path)))
+        .collect()
+}
+
+/// Switch to a branch. If it's in a worktree, print the path to stdout for cd.
+fn switch_to(target: &str, wt_map: &HashMap<String, String>) -> Result<()> {
+    if let Some(wt_path) = wt_map.get(target) {
+        // Branch is in a worktree — print path to stdout for shell wrapper to cd.
+        ui::success(&format!("Switching to `{target}` in worktree `{wt_path}`"));
+        println!("{wt_path}");
+    } else {
+        git::checkout(target)?;
+        ui::success(&format!("Switched to `{target}`"));
+    }
+    Ok(())
+}
+
 pub fn run(name: Option<&str>) -> Result<()> {
     let state = StackState::load()?;
     let current = git::current_branch()?;
+    let wt_map = worktree_map();
 
     // Direct checkout by name or PR number.
     if let Some(arg) = name {
         let target = if let Ok(pr_num) = arg.parse::<u64>() {
-            // Look up branch by PR number.
             state
                 .branches
                 .values()
                 .find(|m| m.pr_number == Some(pr_num))
                 .map(|m| m.name.clone())
-                .ok_or_else(|| anyhow::anyhow!("No branch found with PR #{pr_num}"))?
+                .ok_or_else(|| {
+                    anyhow::anyhow!(
+                        "No branch found with PR #{pr_num}\n  → Run `ez branch` to see all branches"
+                    )
+                })?
         } else {
-            // Direct branch name — must be managed or trunk.
             if !state.is_trunk(arg) && !state.is_managed(arg) {
-                anyhow::bail!("Branch `{arg}` is not tracked by ez");
+                anyhow::bail!(
+                    "Branch `{arg}` is not tracked by ez\n  → Run `ez branch` to see all branches"
+                );
             }
             arg.to_string()
         };
@@ -33,8 +62,7 @@ pub fn run(name: Option<&str>) -> Result<()> {
             return Ok(());
         }
 
-        git::checkout(&target)?;
-        ui::success(&format!("Switched to `{target}`"));
+        switch_to(&target, &wt_map)?;
         return Ok(());
     }
 
@@ -87,8 +115,7 @@ pub fn run(name: Option<&str>) -> Result<()> {
         return Ok(());
     }
 
-    git::checkout(selected)?;
-    ui::success(&format!("Switched to `{selected}`"));
+    switch_to(selected, &wt_map)?;
 
     Ok(())
 }

src/cmd/checkout.rs

@@ -2,22 +2,36 @@ use anyhow::Result;
 
 pub fn run() -> Result<()> {
     // Print a shell function that wraps the ez binary.
-    // The function intercepts `ez worktree create` and `ez worktree delete` to auto-cd.
-    // All other commands pass through to the binary unchanged.
+    // Intercepts commands that output a path to stdout for auto-cd:
+    //   ez worktree create/delete — prints worktree path or repo root
+    //   ez checkout — prints worktree path if branch is in a worktree
     print!(
         r#"# ez shell integration — generated by `ez shell-init`
 # Add to your .bashrc/.zshrc:  eval "$(ez shell-init)"
 
 ez() {{
-    if [ "$1" = "worktree" ] && {{ [ "$2" = "create" ] || [ "$2" = "delete" ]; }}; then
-        local _ez_path
-        _ez_path=$(command ez "$@")
-        local _ez_exit=$?
-        if [ $_ez_exit -eq 0 ] && [ -n "$_ez_path" ] && [ -d "$_ez_path" ]; then
-            cd "$_ez_path" || true
-        fi
-        return $_ez_exit
-    fi
+    case "$1" in
+        worktree)
+            if [ "$2" = "create" ] || [ "$2" = "delete" ]; then
+                local _ez_path
+                _ez_path=$(command ez "$@")
+                local _ez_exit=$?
+                if [ $_ez_exit -eq 0 ] && [ -n "$_ez_path" ] && [ -d "$_ez_path" ]; then
+                    cd "$_ez_path" || true
+                fi
+                return $_ez_exit
+            fi
+            ;;
+        checkout|co)
+            local _ez_path
+            _ez_path=$(command ez "$@")
+            local _ez_exit=$?
+            if [ $_ez_exit -eq 0 ] && [ -n "$_ez_path" ] && [ -d "$_ez_path" ]; then
+                cd "$_ez_path" || true
+            fi
+            return $_ez_exit
+            ;;
+    esac
     command ez "$@"
 }}
 "#