Prompt step by step for the missing base image, ISO, npm deps and Chromium

Offer to build the base QCOW2, download the ISO, run npm ci and install
Chromium (from the npmmirror mirror by default). Let Playwright locate its
own Chromium so macOS works.

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

build-windows-base.sh

@@ -31,6 +31,8 @@ set -euo pipefail
 
 images_dir="$(cd -- "$(dirname -- "${BASH_SOURCE[0]}")" && pwd)"
 downloader="${images_dir}/download-images.sh"
+# Path lookups below must not offer to run this script again.
+export VM_IMAGE_NO_PROMPT=1
 win_dir="${images_dir}/windows11"
 
 usage() {
@@ -116,6 +118,17 @@ if ((!from_img)); then
     || die "install socat or nc (it presses a key at the boot prompt of the ISO)."
 fi
 
+# Without the ISO, offer to download it (needs a terminal).
+if [[ -z "${WIN11_VM_INSTALL_ISO:-}" ]] && ! "$downloader" --print-path windows11 --iso >/dev/null 2>&1; then
+  "$downloader" --print-path windows11 --iso >&2 || true
+  if { : </dev/tty >/dev/tty; } 2>/dev/null; then
+    printf 'Download the Windows 11 ISO now? [y/N] ' >/dev/tty
+    read -r answer </dev/tty || answer=
+    [[ "$answer" == [yY] || "$answer" == [yY][eE][sS] ]] || exit 1
+    "$downloader" windows11 || exit 1
+  fi
+fi
+
 output="${output:-$("$downloader" --print-path windows11)}"
 if [[ -e "$output" && $force -eq 0 ]]; then
   die "${output} exists (it may be the backing file of existing VM disks); use --force or another OUTPUT."

download-images.sh

@@ -156,6 +156,36 @@ The Windows ISO is found automatically in install-iso/ by matching
 EOF
 }
 
+# Ask a yes/no question on the terminal; fails when there is none or the answer
+# is not yes. stdout carries the printed path, so all dialogue goes to /dev/tty.
+ask_yes_no() {
+  local answer
+  { : </dev/tty >/dev/tty; } 2>/dev/null || return 1
+  printf '%s [y/N] ' "$1" >/dev/tty
+  read -r answer </dev/tty || return 1
+  [[ "$answer" == [yY] || "$answer" == [yY][eE][sS] ]]
+}
+
+# Print the base QCOW2 path. When the image does not exist and a terminal is
+# attached, offer to run build-windows-base.sh, which in turn offers to download
+# the ISO. The builder sets VM_IMAGE_NO_PROMPT so its own lookups never ask.
+windows_base_path() {
+  local qcow2 builder="${images_dir}/build-windows-base.sh"
+  if qcow2="$(windows_qcow2_path 2>/dev/null)" && [[ -f "$qcow2" ]]; then
+    printf '%s\n' "$qcow2"
+    return 0
+  fi
+  windows_qcow2_path >/dev/null || true
+  if [[ -z "${VM_IMAGE_NO_PROMPT:-}" && -x "$builder" ]] && ask_yes_no "Build the Windows 11 base image now with build-windows-base.sh?"; then
+    # stdout carries the path, so the build's output goes to the terminal.
+    "$builder" >/dev/tty 2>&1 </dev/tty || return 1
+    windows_qcow2_path
+    return
+  fi
+  # Name the expected path if the ISO fixes it; the caller reports it missing.
+  windows_qcow2_path 2>/dev/null
+}
+
 print_image_path() {
   local target="$1"
   local media="${2:-qcow2}"
@@ -171,7 +201,7 @@ print_image_path() {
       if [[ "$media" == iso ]]; then
         windows_iso_path
       else
-        windows_qcow2_path
+        windows_base_path
       fi
       ;;
     *)
@@ -416,7 +446,27 @@ download_windows_iso() {
     printf 'Error: node is required to get the Windows 11 ISO URL.\n' >&2
     exit 1
   fi
-  url="$(node "${images_dir}/nodejs/get-windows-iso-url.js" --arch "$windows_arch")"
+  if [[ ! -d "${images_dir}/nodejs/node_modules/playwright-core" ]]; then
+    printf 'Error: the Node.js dependencies are not installed (npm ci has not been run in %s/nodejs).\n' \
+      "$images_dir" >&2
+    command -v npm >/dev/null 2>&1 || { printf 'Error: npm is required; install Node.js with npm.\n' >&2; exit 1; }
+    ask_yes_no "Run npm ci in ${images_dir}/nodejs now?" || exit 1
+    (cd "${images_dir}/nodejs" && npm ci) || exit 1
+  fi
+  local status=0
+  url="$(node "${images_dir}/nodejs/get-windows-iso-url.js" --arch "$windows_arch")" || status=$?
+  if ((status == 2)) && [[ -z "${CHROME_PATH:-}" ]]; then
+    # Exit status 2 means Chromium was not found (the script has said so).
+    ask_yes_no "Install Chromium with playwright-core now?" || exit 1
+    # Default to the npmmirror mirror (the official CDN is slow in China); set
+    # PLAYWRIGHT_DOWNLOAD_HOST to override it.
+    (cd "${images_dir}/nodejs" \
+      && PLAYWRIGHT_DOWNLOAD_HOST="${PLAYWRIGHT_DOWNLOAD_HOST:-https://cdn.npmmirror.com/binaries/playwright}" \
+        npx playwright-core install chromium) || exit 1
+    url="$(node "${images_dir}/nodejs/get-windows-iso-url.js" --arch "$windows_arch")" || exit 1
+  elif ((status != 0)); then
+    exit "$status"
+  fi
   [[ -n "$url" ]] || { printf 'Error: no Windows 11 ISO URL.\n' >&2; exit 1; }
   name="${url%%\?*}"
   name="${name##*/}"

nodejs/get-windows-iso-url.js

@@ -5,12 +5,11 @@
 // Usage: node get-windows-iso-url.js [--arch x64|arm64] [--lang NAME]
 // Environment:
 //   PLAYWRIGHT_CORE  playwright-core directory (default: node_modules here)
-//   CHROME_PATH      Chromium executable (default: newest one in ~/.cache/ms-playwright)
+//   CHROME_PATH      Chromium executable (default: the one Playwright installed)
 // The URL expires after about 24 hours and may be bound to the IP that
 // requested it. Only the URL goes to stdout; logs go to stderr.
 
 const fs = require('fs');
-const os = require('os');
 const path = require('path');
 
 const args = process.argv.slice(2);
@@ -28,8 +27,7 @@ Options:
 
 Environment:
   PLAYWRIGHT_CORE      playwright-core directory (default: node_modules here)
-  CHROME_PATH          Chromium executable (default: newest one in
+  CHROME_PATH          Chromium executable (default: the one Playwright installed)
-                       ~/.cache/ms-playwright)
 
 Examples:
   node get-windows-iso-url.js --arch x64 --lang "Chinese Simplified"
@@ -60,17 +58,20 @@ function findPlaywright() {
   process.exit(2);
 }
 
-function findChrome() {
+// CHROME_PATH wins; otherwise Playwright picks the Chromium it installed (in
-  if (process.env.CHROME_PATH) return process.env.CHROME_PATH;
+// its own per-OS cache, PLAYWRIGHT_BROWSERS_PATH if set).
-  const root = path.join(os.homedir(), '.cache/ms-playwright');
+function launchOptions(chromium) {
-  const dirs = fs.existsSync(root) ? fs.readdirSync(root).filter(d => /^chromium-\d+$/.test(d)).sort() : [];
+  if (process.env.CHROME_PATH) return { executablePath: process.env.CHROME_PATH, headless: true };
-  if (!dirs.length) { console.error('Chromium not found: set CHROME_PATH or run npx playwright-core install chromium'); process.exit(2); }
+  if (!fs.existsSync(chromium.executablePath())) {
-  return path.join(root, dirs.pop(), 'chrome-linux64/chrome');
+    console.error('Chromium not found: set CHROME_PATH or run npx playwright-core install chromium');
+    process.exit(2);
+  }
+  return { headless: true };
 }
 
 (async () => {
   const { chromium } = require(findPlaywright());
-  const browser = await chromium.launch({ executablePath: findChrome(), headless: true });
+  const browser = await chromium.launch(launchOptions(chromium));
   try {
     const ctx = await browser.newContext({
       locale: 'en-US',