fix: run checkout hooks when worktree already exists (#71) (#72)

Previously, `wt checkout` skipped pre/post checkout hooks when the
worktree already existed due to an early return. Now hooks run
regardless of whether the worktree is new or existing.

Author: timvw

docs/configuration.md

@@ -98,7 +98,7 @@ Hooks let you run custom commands before or after `wt` operations. Define them i
 | `pre_pr` / `post_pr` | Before/after `wt pr` |
 | `pre_mr` / `post_mr` | Before/after `wt mr` |
 
-Hooks only run when a **new worktree is actually created** (or removed). If a worktree already exists, the early-return path skips hooks entirely.
+Checkout hooks (`pre_checkout` / `post_checkout`) run both when a new worktree is created **and** when checking out an existing worktree. Create and remove hooks run only when a worktree is actually created or removed.
 
 **Environment variables** available in hook commands:
 

e2e/scenarios/hooks.yaml

@@ -51,6 +51,44 @@ scenarios:
         expect:
           output_contains: "HOOK_RAN"
 
+  - name: checkout_hooks_run_on_existing_worktree
+    description: Pre/post checkout hooks execute even when worktree already exists
+    skip_os: [windows]
+    skip_shellenv: true
+    setup:
+      - create_branch: existing-co-branch
+    steps:
+      # First checkout creates the worktree (no hook config yet)
+      - run: $WT_BIN checkout existing-co-branch
+        expect:
+          exit_code: 0
+      - cd: $REPO_DIR
+      # Second checkout with hooks configured — hooks should still run
+      - run: mkdir -p "$TEST_DIR/config" && printf '[hooks]\npost_checkout = ["touch $WT_PATH/.existing-hook-ran"]\n' > "$TEST_DIR/config/config.toml" && WT_CONFIG="$TEST_DIR/config/config.toml" $WT_BIN checkout existing-co-branch
+        expect:
+          exit_code: 0
+          output_contains: "already exists"
+      - run: test -f "$WORKTREE_ROOT/test-repo/existing-co-branch/.existing-hook-ran" && echo "HOOK_RAN" || echo "HOOK_MISSING"
+        expect:
+          output_contains: "HOOK_RAN"
+
+  - name: pre_checkout_hook_aborts_existing_worktree
+    description: Pre-checkout hook failure prevents checkout of existing worktree
+    skip_os: [windows]
+    skip_shellenv: true
+    setup:
+      - create_branch: abort-co-branch
+    steps:
+      # First checkout creates the worktree
+      - run: $WT_BIN checkout abort-co-branch
+        expect:
+          exit_code: 0
+      - cd: $REPO_DIR
+      # Second checkout with failing pre_checkout hook — should abort
+      - run: mkdir -p "$TEST_DIR/config" && printf '[hooks]\npre_checkout = ["false"]\n' > "$TEST_DIR/config/config.toml" && WT_CONFIG="$TEST_DIR/config/config.toml" $WT_BIN checkout abort-co-branch
+        expect:
+          exit_code: 1
+
   - name: pre_remove_hook_runs
     description: Pre-remove hook executes before worktree removal
     skip_os: [windows]

main.go

@@ -915,6 +915,16 @@ var checkoutCmd = &cobra.Command{
 
 		// Check if worktree already exists
 		if existingPath, exists := worktreeExists(branch); exists {
+			hookEnv := buildHookEnv(info, branch, existingPath)
+
+			// Run pre-checkout hooks
+			if err := runHooks("pre_checkout", getHooks("pre_checkout"), hookEnv); err != nil {
+				return fmt.Errorf("pre-checkout hook failed: %w", err)
+			}
+
+			// Run post-checkout hooks (warn only)
+			_ = runHooks("post_checkout", getHooks("post_checkout"), hookEnv)
+
 			if isJSONOutput() {
 				return emitJSONSuccess(cmd, map[string]any{
 					"status":      "exists",