fs: don't alter user provided `options` object

This patch makes a copy of the `options` object before the fs module
functions alter it.

PR-URL: https://github.com/nodejs/node/pull/7831
Fixes: https://github.com/nodejs/node/pull/7655
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Nicu Micleușanu <micnic90@gmail.com>
Reviewed-By: Rod Vagg <rod@vagg.org>

1 files changed, 98 insertions, 0 deletions

diff --git a/test/parallel/test-fs-options-immutable.js b/test/parallel/test-fs-options-immutable.js
new file mode 100644
index 0000000000..47796a94a5
--- /dev/null
+++ b/test/parallel/test-fs-options-immutable.js
@@ -0,0 +1,98 @@
+'use strict';
+
+/*
+ * These tests make sure that the `options` object passed to these functions are
+ * never altered.
+ *
+ * Refer: https://github.com/nodejs/node/issues/7655
+ */
+
+const common = require('../common');
+const assert = require('assert');
+const path = require('path');
+const fs = require('fs');
+const errHandler = (e) => assert.ifError(e);
+const options = Object.freeze({});
+common.refreshTmpDir();
+
+{
+  assert.doesNotThrow(() =>
+    fs.readFile(__filename, options, common.mustCall(errHandler))
+  );
+  assert.doesNotThrow(() => fs.readFileSync(__filename, options));
+}
+
+{
+  assert.doesNotThrow(() =>
+    fs.readdir(__dirname, options, common.mustCall(errHandler))
+  );
+  assert.doesNotThrow(() => fs.readdirSync(__dirname, options));
+}
+
+{
+  const sourceFile = path.resolve(common.tmpDir, 'test-readlink');
+  const linkFile = path.resolve(common.tmpDir, 'test-readlink-link');
+
+  fs.writeFileSync(sourceFile, '');
+  fs.symlinkSync(sourceFile, linkFile);
+
+  assert.doesNotThrow(() =>
+    fs.readlink(linkFile, options, common.mustCall(errHandler))
+  );
+  assert.doesNotThrow(() => fs.readlinkSync(linkFile, options));
+}
+
+{
+  const fileName = path.resolve(common.tmpDir, 'writeFile');
+  assert.doesNotThrow(() => fs.writeFileSync(fileName, 'ABCD', options));
+  assert.doesNotThrow(() =>
+    fs.writeFile(fileName, 'ABCD', options, common.mustCall(errHandler))
+  );
+}
+
+{
+  const fileName = path.resolve(common.tmpDir, 'appendFile');
+  assert.doesNotThrow(() => fs.appendFileSync(fileName, 'ABCD', options));
+  assert.doesNotThrow(() =>
+    fs.appendFile(fileName, 'ABCD', options, common.mustCall(errHandler))
+  );
+}
+
+if (!common.isAix) {
+  // TODO(thefourtheye) Remove this guard once
+  // https://github.com/nodejs/node/issues/5085 is fixed
+  {
+    let watch;
+    assert.doesNotThrow(() => watch = fs.watch(__filename, options, () => {}));
+    watch.close();
+  }
+
+  {
+    assert.doesNotThrow(() => fs.watchFile(__filename, options, () => {}));
+    fs.unwatchFile(__filename);
+  }
+}
+
+{
+  assert.doesNotThrow(() => fs.realpathSync(__filename, options));
+  assert.doesNotThrow(() =>
+    fs.realpath(__filename, options, common.mustCall(errHandler))
+  );
+}
+
+{
+  const tempFileName = path.resolve(common.tmpDir, 'mkdtemp-');
+  assert.doesNotThrow(() => fs.mkdtempSync(tempFileName, options));
+  assert.doesNotThrow(() =>
+    fs.mkdtemp(tempFileName, options, common.mustCall(errHandler))
+  );
+}
+
+{
+  const fileName = path.resolve(common.tmpDir, 'streams');
+  assert.doesNotThrow(() => {
+    fs.WriteStream(fileName, options).once('open', () => {
+      assert.doesNotThrow(() => fs.ReadStream(fileName, options));
+    });
+  });
+}