Dual packaging, without breaking existing consumers (#628)

Co-authored-by: Yasumasa Ashida <ys.ashida@gmail.com>

test/package/smoke.cjs

@@ -0,0 +1,100 @@
+/* eslint-disable */
+/**
+ * Verifies the *packed* bowser package against the surface real consumers use.
+ *
+ *   node test/package/smoke.cjs <path-to-bowser-x.y.z.tgz>
+ *
+ * The tarball is extracted into a throwaway directory as ./node_modules/bowser
+ * and `assertions.cjs` is run next to it, so bare specifiers such as
+ * `require('bowser')` and `require('bowser/es5.js')` resolve exactly as they
+ * would after `npm install bowser`.
+ *
+ * Run this on every Node version bowser supports — that is the point of it.
+ * See `.github/workflows/pull-request.yml`.
+ *
+ * Deliberately ES5-compatible CommonJS so it runs on Node 12.16.3.
+ */
+var cp = require('child_process');
+var fs = require('fs');
+var os = require('os');
+var path = require('path');
+var zlib = require('zlib');
+
+var tarball = process.argv[2];
+
+if (!tarball) {
+  console.error('usage: node test/package/smoke.cjs <path-to-tarball.tgz>');
+  console.error('');
+  console.error('Create one with:');
+  console.error('  npm version 0.0.0-ci --no-git-tag-version --allow-same-version');
+  console.error('  npm pack');
+  process.exit(1);
+}
+
+tarball = path.resolve(tarball);
+if (!fs.existsSync(tarball)) {
+  console.error('no such tarball: ' + tarball);
+  process.exit(1);
+}
+
+var tmp = fs.mkdtempSync(path.join(os.tmpdir(), 'bowser-smoke-'));
+var modules = path.join(tmp, 'node_modules');
+fs.mkdirSync(modules);
+
+/**
+ * Extracts an npm tarball using only Node built-ins, so the test needs no
+ * external `tar`/`npm` process and runs identically on every OS and every
+ * Node version in the support matrix.
+ *
+ * npm tarballs are gzipped ustar archives of regular files (npm rejects
+ * anything else at publish time), which is the only shape handled here:
+ * pax/global extended headers and directory entries are skipped, and parent
+ * directories are created per file instead.
+ */
+function extractNpmTarball(tgz, dest) {
+  var buf = zlib.gunzipSync(fs.readFileSync(tgz));
+  var offset = 0;
+  while (offset + 512 <= buf.length) {
+    var header = buf.slice(offset, offset + 512);
+    offset += 512;
+    if (header[0] === 0) break; // zero block: end of archive
+    var name = header.slice(0, 100).toString('utf8').replace(/\0[\s\S]*$/, '');
+    var prefix = header.slice(345, 500).toString('utf8').replace(/\0[\s\S]*$/, '');
+    if (prefix) name = prefix + '/' + name;
+    var size = parseInt(header.slice(124, 136).toString('utf8'), 8) || 0;
+    var type = header[156];
+    if (type === 48 /* '0' */ || type === 0) {
+      var target = path.join(dest, name);
+      if (target.indexOf(dest + path.sep) !== 0) {
+        throw new Error('tarball entry escapes destination: ' + name);
+      }
+      fs.mkdirSync(path.dirname(target), { recursive: true });
+      fs.writeFileSync(target, buf.slice(offset, offset + size));
+    }
+    offset += Math.ceil(size / 512) * 512;
+  }
+}
+
+// npm tarballs always unpack to a single top-level `package/` directory.
+extractNpmTarball(tarball, modules);
+fs.renameSync(path.join(modules, 'package'), path.join(modules, 'bowser'));
+
+var runner = path.join(tmp, 'assertions.cjs');
+fs.writeFileSync(runner, fs.readFileSync(path.join(__dirname, 'assertions.cjs')));
+
+var result = cp.spawnSync(process.execPath, [runner], { cwd: tmp, stdio: 'inherit' });
+
+try {
+  // fs.rmSync landed in Node 14.14; recursive fs.rmdirSync (12.10+) covers the
+  // bottom of the matrix. Both work on Windows, unlike shelling out to `rm`.
+  if (fs.rmSync) {
+    fs.rmSync(tmp, { recursive: true, force: true });
+  } else {
+    fs.rmdirSync(tmp, { recursive: true });
+  }
+} catch (e) { /* best effort */ }
+
+if (result.status !== 0) {
+  console.error('\npackage smoke test FAILED on Node ' + process.versions.node);
+  process.exit(result.status || 1);
+}