fix: dont use gulp streams for simple copying

scripts/copy-blockly.js

@@ -1,20 +1,7 @@
 #!/usr/bin/env node
 const fs = require('fs').promises;
 const path = require('path');
-
-async function copyDir(src, dest) {
-  await fs.mkdir(dest, {recursive: true});
-  const entries = await fs.readdir(src, {withFileTypes: true});
-  for (const entry of entries) {
-    const srcPath = path.join(src, entry.name);
-    const destPath = path.join(dest, entry.name);
-    if (entry.isDirectory()) {
-      await copyDir(srcPath, destPath);
-    } else if (entry.isFile()) {
-      await fs.copyFile(srcPath, destPath);
-    }
-  }
-}
+const {copyDirectoryContents} = require('./copy-helpers');
 
 (async () => {
   const destRoot = path.resolve(__dirname, '..', 'examples', 'lib');
@@ -54,7 +41,7 @@ async function copyDir(src, dest) {
 
     // Copy the entire blockly package into destRoot (preserves README, dist, msg, media, etc.)
     try {
-      await copyDir(blocklyDir, blocklyRoot);
+      await copyDirectoryContents(blocklyDir, blocklyRoot);
       console.log('Blockly copied to', blocklyRoot);
     } catch (e) {
       console.error('Failed to copy Blockly package:', e);
@@ -88,7 +75,7 @@ async function copyDir(src, dest) {
                 distExists = false;
               }
               if (distExists) {
-                await copyDir(srcDist, path.join(dest, 'dist'));
+                await copyDirectoryContents(srcDist, path.join(dest, 'dist'));
                 copiedLocal.push(shortName);
                 console.log(
                   `Copied local @blockly/${shortName}/dist to ${path.join(

scripts/copy-helpers.js

@@ -0,0 +1,112 @@
+/**
+ * @license
+ * Copyright 2026 Google LLC
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+/**
+ * @fileoverview Shared filesystem copy helpers (binary-safe, no gulp streams).
+ */
+
+const fs = require('fs');
+const path = require('path');
+
+/**
+ * True if the path looks like a glob pattern (not a literal file path).
+ * @param {string} filePath Absolute or normalized path.
+ * @returns {boolean} Whether the path contains glob metacharacters.
+ */
+function hasGlobPattern(filePath) {
+  return /[*?[\]]/.test(filePath);
+}
+
+/**
+ * Expand a glob pattern to matching paths. Prefer Node's `fs.globSync` (Node
+ * 22+); older Node uses the `glob` package (pulled in by gulp).
+ * @param {string} pattern Absolute path that may contain glob metacharacters.
+ * @returns {!Array<string>} Matching paths from the filesystem.
+ */
+function expandGlob(pattern) {
+  if (typeof fs.globSync === 'function') {
+    return fs.globSync(pattern);
+  }
+  return require('glob').sync(pattern);
+}
+
+/**
+ * Expand `blocklyDemoConfig.files`-style entries to concrete paths.
+ * @param {!Array<string>} sources Paths relative to cwd or absolute.
+ * @returns {!Array<string>} Absolute paths to files (directories skipped).
+ */
+function expandSourcePaths(sources) {
+  const out = [];
+  for (const src of sources) {
+    const resolved = path.resolve(src);
+    if (!hasGlobPattern(resolved)) {
+      out.push(resolved);
+      continue;
+    }
+    const matches = expandGlob(resolved);
+    for (const m of matches) {
+      if (fs.existsSync(m) && fs.statSync(m).isFile()) {
+        out.push(m);
+      }
+    }
+  }
+  return out;
+}
+
+/**
+ * Copy files under baseDir into destRoot, preserving directory structure
+ * relative to baseDir. Skips missing sources.
+ * Uses fs.copyFileSync so binary files are not corrupted.
+ * Glob patterns in `sources` are expanded.
+ * @param {!Array<string>} sources Source file paths (may include globs).
+ * @param {string} baseDir Base directory (e.g. 'examples' or 'plugins').
+ * @param {string} destRoot Destination root (e.g. 'gh-pages/examples').
+ */
+function copyFilesWithBase(sources, baseDir, destRoot) {
+  const baseResolved = path.resolve(baseDir);
+  const destRootResolved = path.resolve(destRoot);
+  const sourceFiles = expandSourcePaths(sources);
+  for (const srcPath of sourceFiles) {
+    if (!fs.existsSync(srcPath)) {
+      continue;
+    }
+    if (!fs.statSync(srcPath).isFile()) {
+      continue;
+    }
+    const rel = path.relative(baseResolved, path.resolve(srcPath));
+    if (rel.startsWith('..') || path.isAbsolute(rel)) {
+      throw new Error(
+        `Source ${srcPath} is not under base directory ${baseDir}`,
+      );
+    }
+    const destPath = path.join(destRootResolved, rel);
+    fs.mkdirSync(path.dirname(destPath), {recursive: true});
+    fs.copyFileSync(srcPath, destPath);
+  }
+}
+
+/**
+ * Copy a directory tree into dest. If dest already exists as a directory,
+ * the contents of src are merged/copied into it.
+ * No-op if src does not exist. Binary-safe.
+ * @param {string} src Source directory path.
+ * @param {string} dest Destination directory path.
+ * @returns {!Promise<void>} Resolves when the copy completes.
+ */
+async function copyDirectoryContents(src, dest) {
+  try {
+    await fs.promises.access(src);
+  } catch {
+    return;
+  }
+  await fs.promises.mkdir(dest, {recursive: true});
+  await fs.promises.cp(src, dest, {recursive: true});
+}
+
+module.exports = {
+  copyFilesWithBase,
+  copyDirectoryContents,
+};

scripts/gh-predeploy.js

@@ -15,6 +15,8 @@ const path = require('path');
 const showdown = require('showdown');
 gulp.header = require('gulp-header');
 
+const {copyFilesWithBase, copyDirectoryContents} = require('./copy-helpers');
+
 const appDirectory = fs.realpathSync(process.cwd());
 const resolveApp = (relativePath) => path.resolve(appDirectory, relativePath);
 
@@ -288,18 +290,16 @@ function createReadmePage(pluginDir, isLocal) {
  * @param {string} pluginDir The directory with the plugin source files.
  * @param {boolean} isLocal True if building for a local test. False if
  *     building for gh-pages.
- * @returns {*} gulp stream
  */
 function preparePlugin(pluginDir, isLocal) {
   console.log(`Preparing ${pluginDir} plugin for deployment.`);
   createPluginPage(pluginDir, isLocal);
   createReadmePage(pluginDir, isLocal);
-  return gulp
-    .src(['./plugins/' + pluginDir + '/build/test_bundle.js'], {
-      base: './plugins/',
-      allowEmpty: true,
-    })
-    .pipe(gulp.dest('./gh-pages/plugins/'));
+  copyFilesWithBase(
+    [path.join('plugins', pluginDir, 'build', 'test_bundle.js')],
+    'plugins',
+    path.join('gh-pages', 'plugins'),
+  );
 }
 
 /**
@@ -328,8 +328,9 @@ function prepareToDeployPlugins(done) {
   const folders = getPluginFolders();
   return gulp.parallel(
     folders.map(function (folder) {
-      return function preDeployPlugin() {
-        return preparePlugin(folder, false);
+      return function preDeployPlugin(done) {
+        preparePlugin(folder, false);
+        done();
       };
     }),
   )(done);
@@ -344,8 +345,9 @@ function prepareLocalPlugins(done) {
   const folders = getPluginFolders();
   return gulp.parallel(
     folders.map(function (folder) {
-      return function preDeployPlugin() {
-        return preparePlugin(folder, true);
+      return function preDeployPlugin(done) {
+        preparePlugin(folder, true);
+        done();
       };
     }),
   )(done);
@@ -445,7 +447,6 @@ function createExamplePage(pageRoot, pagePath, demoConfig, isLocal) {
  * @param {boolean} isLocal True if building for a local test. False if
  *     building for gh-pages.
  * @param {Function} done Completed callback.
- * @returns {Function | undefined} Gulp task.
  */
 function prepareExample(exampleDir, isLocal, done) {
   const baseDir = 'examples';
@@ -468,12 +469,13 @@ function prepareExample(exampleDir, isLocal, done) {
 
   // Special case: do a straight copy for the devsite demo, with no wrappers.
   if (packageJson.name == 'blockly-devsite-demo') {
-    return gulp
-      .src(
-        fileList.map((f) => path.join(baseDir, exampleDir, f)),
-        {base: baseDir, allowEmpty: true},
-      )
-      .pipe(gulp.dest('./gh-pages/examples/'));
+    copyFilesWithBase(
+      fileList.map((f) => path.join(baseDir, exampleDir, f)),
+      baseDir,
+      path.join('gh-pages', 'examples'),
+    );
+    done();
+    return;
   }
 
   // All other examples.
@@ -487,14 +489,14 @@ function prepareExample(exampleDir, isLocal, done) {
   // Copy over all other files mentioned in the demoConfig to the
   // correct directory.
   const assets = fileList.filter((f) => !pageRegex.test(f));
-  let stream;
   if (assets.length) {
-    stream = gulp.src(
+    copyFilesWithBase(
       assets.map((f) => path.join(baseDir, exampleDir, f)),
-      {base: baseDir, allowEmpty: true},
+      baseDir,
+      path.join('gh-pages', 'examples'),
     );
   }
-  return stream.pipe(gulp.dest('./gh-pages/examples/'));
+  done();
 }
 
 /**
@@ -517,20 +519,17 @@ function getExampleFolders() {
  *
  * This is treated separately from other examples because it doesn't
  * get the same page chrome added to it.
- * @returns {Function | undefined} Gulp task.
  */
-function prepareDeveloperTools() {
+async function prepareDeveloperTools() {
   const baseDir = 'examples';
   const devToolsDir = 'developer-tools';
   console.log(`Preparing developer-tools for deployment.`);
 
-  // Create target folder, if it doesn't exist.
-  fs.mkdirSync(path.join('gh-pages', baseDir, devToolsDir), {recursive: true});
-
-  // Copy all files from `dist/` subdirectory into the corresponding gh-pages directory
-  return gulp
-    .src('./examples/developer-tools/dist/*')
-    .pipe(gulp.dest('./gh-pages/examples/developer-tools'));
+  // Copy all files from `dist/` into the gh-pages developer-tools directory
+  await copyDirectoryContents(
+    path.join(baseDir, devToolsDir, 'dist'),
+    path.join('gh-pages', baseDir, devToolsDir),
+  );
 }
 
 /**