test: add cpSync error handling test

Add test to ensure fs.cpSync properly handles directory iteration errors
without causing process abort.

Author: gushiaoke

test/parallel/test-fs-cpsync-error-handling.js

@@ -0,0 +1,86 @@
+'use strict';
+
+// Test that fs.cpSync properly handles directory iteration errors
+// instead of causing process abort.
+//
+// This test ensures that when directory_iterator construction fails
+// (e.g., due to permission issues or malformed paths), the error
+// is properly converted to a JavaScript exception rather than
+// triggering std::terminate or __libcpp_verbose_abort.
+
+const common = require('../common');
+const { cpSync, mkdirSync, writeFileSync } = require('fs');
+const { join } = require('path');
+const assert = require('assert');
+const tmpdir = require('../common/tmpdir');
+
+tmpdir.refresh();
+
+// Test 1: Copying from non-existent directory should throw, not abort
+{
+  const nonExistent = join(tmpdir.path, 'does-not-exist');
+  const dest = join(tmpdir.path, 'dest1');
+  
+  assert.throws(
+    () => cpSync(nonExistent, dest, { recursive: true }),
+    {
+      code: 'ENOENT',
+      message: /ENOENT/
+    },
+    'cpSync should throw ENOENT for non-existent source directory'
+  );
+}
+
+// Test 2: Copying directory with unreadable subdirectory
+// (This test is platform-specific and may be skipped on Windows)
+if (!common.isWindows) {
+  const srcDir = join(tmpdir.path, 'src-unreadable');
+  const unreadableSubdir = join(srcDir, 'unreadable');
+  const dest = join(tmpdir.path, 'dest2');
+  
+  mkdirSync(srcDir);
+  mkdirSync(unreadableSubdir);
+  writeFileSync(join(unreadableSubdir, 'file.txt'), 'content');
+  
+  try {
+    require('fs').chmodSync(unreadableSubdir, 0o000);
+    
+    // Should throw error, not abort
+    assert.throws(
+      () => cpSync(srcDir, dest, { recursive: true }),
+      {
+        code: 'EACCES',
+      },
+      'cpSync should throw EACCES for unreadable directory'
+    );
+  } finally {
+    // Restore permissions for cleanup
+    require('fs').chmodSync(unreadableSubdir, 0o755);
+  }
+}
+
+// Test 3: Basic successful copy to ensure fix doesn't break normal operation
+{
+  const srcDir = join(tmpdir.path, 'src-normal');
+  const dest = join(tmpdir.path, 'dest-normal');
+  
+  mkdirSync(srcDir);
+  writeFileSync(join(srcDir, 'file1.txt'), 'content1');
+  mkdirSync(join(srcDir, 'subdir'));
+  writeFileSync(join(srcDir, 'subdir', 'file2.txt'), 'content2');
+  
+  // Should not throw
+  cpSync(srcDir, dest, { recursive: true });
+  
+  const fs = require('fs');
+  assert.ok(fs.existsSync(join(dest, 'file1.txt')));
+  assert.ok(fs.existsSync(join(dest, 'subdir', 'file2.txt')));
+  assert.strictEqual(
+    fs.readFileSync(join(dest, 'file1.txt'), 'utf8'),
+    'content1'
+  );
+  assert.strictEqual(
+    fs.readFileSync(join(dest, 'subdir', 'file2.txt'), 'utf8'),
+    'content2'
+  );
+}