feat(ai): run postCd hooks before launching AI process (#144)

When users configure postCd hooks (e.g., source ./vars.sh), gtr cd runs
them but gtr ai did not. This meant AI tools launched via gtr ai didn't
get the worktree's environment setup.

Add run_hooks_export to lib/hooks.sh — a variant of run_hooks that evals
hooks without subshell isolation so exported env vars persist. Call sites
wrap it in an explicit subshell for safety with set -e.

Closes #144

Author: helizaga

lib/commands/ai.sh

@@ -39,5 +39,13 @@ cmd_ai() {
   log_info "Directory: $worktree_path"
   log_info "Branch: $branch"
 
-  ai_start "$worktree_path" "${ai_args[@]}"
+  # Run postCd hooks + AI in a subshell so hook env vars propagate to AI
+  (
+    cd "$worktree_path" || exit 1
+    run_hooks_export "postCd" \
+      REPO_ROOT="$repo_root" \
+      WORKTREE_PATH="$worktree_path" \
+      BRANCH="$branch"
+    ai_start "$worktree_path" "${ai_args[@]}"
+  )
 }

lib/commands/create.sh

@@ -192,7 +192,7 @@ cmd_create() {
 
   # Auto-launch editor/AI or show next steps
   [ "$open_editor" -eq 1 ] && { _auto_launch_editor "$worktree_path" || true; }
-  [ "$start_ai" -eq 1 ] && { _auto_launch_ai "$worktree_path" || true; }
+  [ "$start_ai" -eq 1 ] && { _auto_launch_ai "$worktree_path" "$repo_root" "$branch_name" || true; }
   if [ "$open_editor" -eq 0 ] && [ "$start_ai" -eq 0 ]; then
     _post_create_next_steps "$branch_name" "$folder_name" "$folder_override" "$repo_root" "$base_dir" "$prefix"
   fi

lib/hooks.sh

@@ -84,3 +84,42 @@ run_hooks_in() {
 
   return $result
 }
+
+# Run hooks in current shell without subshell isolation
+# Env vars set by hooks (e.g., source ./vars.sh) persist in the calling shell.
+# IMPORTANT: Call from within a subshell to avoid polluting the main script.
+# Usage: run_hooks_export phase [env_vars...]
+# Example: ( cd "$dir" && run_hooks_export postCd REPO_ROOT="$root" )
+run_hooks_export() {
+  local phase="$1"
+  shift
+
+  local hooks
+  hooks=$(cfg_get_all "gtr.hook.$phase" "hooks.$phase")
+
+  if [ -z "$hooks" ]; then
+    return 0
+  fi
+
+  log_step "Running $phase hooks..."
+
+  # Export env vars so hooks and child processes can see them
+  local kv
+  for kv in "$@"; do
+    # shellcheck disable=SC2163
+    export "$kv"
+  done
+
+  local hook_count=0
+  while IFS= read -r hook; do
+    [ -z "$hook" ] && continue
+
+    hook_count=$((hook_count + 1))
+    log_info "Hook $hook_count: $hook"
+
+    # eval directly (no subshell) so exports persist
+    eval "$hook" || log_warn "Hook $hook_count failed (continuing)"
+  done <<EOF
+$hooks
+EOF
+}

lib/launch.sh

@@ -41,15 +41,29 @@ _auto_launch_editor() {
 }
 
 # Auto-launch AI tool for a worktree
+# Usage: _auto_launch_ai <worktree_path> [repo_root] [branch]
+# When repo_root and branch are provided, runs postCd hooks before launch.
 _auto_launch_ai() {
   local worktree_path="$1"
+  local repo_root="${2:-}" branch="${3:-}"
   local ai_tool
   ai_tool=$(_cfg_ai_default)
   if [ "$ai_tool" = "none" ]; then
     log_warn "No AI tool configured. Set with: git gtr config set gtr.ai.default claude"
   else
     load_ai_adapter "$ai_tool" || return 1
     log_step "Starting $ai_tool..."
-    ai_start "$worktree_path" || log_warn "Failed to start AI tool"
+    if [ -n "$repo_root" ] && [ -n "$branch" ]; then
+      (
+        cd "$worktree_path" || exit 1
+        run_hooks_export "postCd" \
+          REPO_ROOT="$repo_root" \
+          WORKTREE_PATH="$worktree_path" \
+          BRANCH="$branch"
+        ai_start "$worktree_path"
+      ) || log_warn "Failed to start AI tool"
+    else
+      ai_start "$worktree_path" || log_warn "Failed to start AI tool"
+    fi
   fi
 }

tests/hooks.bats

@@ -88,3 +88,49 @@ teardown() {
   run_hooks postCreate REPO_ROOT="$TEST_REPO" BRANCH="test-branch"
   [ "$(cat "$TEST_REPO/vars")" = "$TEST_REPO|test-branch" ]
 }
+
+# ── run_hooks_export tests ───────────────────────────────────────────────────
+
+@test "run_hooks_export returns 0 when no hooks configured" {
+  run run_hooks_export postCd REPO_ROOT="$TEST_REPO"
+  [ "$status" -eq 0 ]
+}
+
+@test "run_hooks_export executes hook" {
+  git config --add gtr.hook.postCd 'touch "$REPO_ROOT/hook-ran"'
+  (cd "$TEST_REPO" && run_hooks_export postCd REPO_ROOT="$TEST_REPO")
+  [ -f "$TEST_REPO/hook-ran" ]
+}
+
+@test "run_hooks_export env vars propagate to child processes" {
+  git config --add gtr.hook.postCd 'export MY_CUSTOM_VAR="from-hook"'
+  # Run hook then check env in same subshell — simulates ai_start inheriting env
+  result=$(
+    cd "$TEST_REPO"
+    run_hooks_export postCd REPO_ROOT="$TEST_REPO"
+    echo "$MY_CUSTOM_VAR"
+  )
+  [ "$result" = "from-hook" ]
+}
+
+@test "run_hooks_export continues after hook failure" {
+  git config --add gtr.hook.postCd "false"
+  git config --add gtr.hook.postCd 'touch "$REPO_ROOT/second-ran"'
+  (cd "$TEST_REPO" && run_hooks_export postCd REPO_ROOT="$TEST_REPO") || true
+  [ -f "$TEST_REPO/second-ran" ]
+}
+
+@test "run_hooks_export passes REPO_ROOT WORKTREE_PATH BRANCH" {
+  git config --add gtr.hook.postCd 'echo "$REPO_ROOT|$WORKTREE_PATH|$BRANCH" > "$REPO_ROOT/env-check"'
+  (cd "$TEST_REPO" && run_hooks_export postCd \
+    REPO_ROOT="$TEST_REPO" \
+    WORKTREE_PATH="/tmp/wt" \
+    BRANCH="my-branch")
+  [ "$(cat "$TEST_REPO/env-check")" = "$TEST_REPO|/tmp/wt|my-branch" ]
+}
+
+@test "run_hooks_export does not leak env to parent shell" {
+  git config --add gtr.hook.postCd 'export LEAK_TEST="leaked"'
+  (cd "$TEST_REPO" && run_hooks_export postCd REPO_ROOT="$TEST_REPO")
+  [ -z "${LEAK_TEST:-}" ]
+}