fs: add runtime deprecate for file stream open()

WriteStream.open() and ReadStream.open() are undocumented internal
APIs that do not make sense to use in userland. File streams should
always be opened through their corresponding factory methods
(fs.createWriteStream() and fs.createReadStream()) or by passing a file
descriptor in options.

PR-URL: https://github.com/nodejs/node/pull/29061
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>
Reviewed-By: Jeremiah Senkpiel <fishrock123@rocketmail.com>
Reviewed-By: João Reis <reis@janeasystems.com>
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>

2 files changed, 49 insertions, 0 deletions

diff --git a/test/parallel/test-fs-read-stream-patch-open.js b/test/parallel/test-fs-read-stream-patch-open.js
new file mode 100644
index 0000000000..80f8888de3
--- /dev/null
+++ b/test/parallel/test-fs-read-stream-patch-open.js
@@ -0,0 +1,15 @@
+'use strict';
+const common = require('../common');
+const fs = require('fs');
+
+common.expectWarning(
+  'DeprecationWarning',
+  'ReadStream.prototype.open() is deprecated', 'DEP0XXX');
+const s = fs.createReadStream('asd')
+  // We don't care about errors in this test.
+  .on('error', () => {});
+s.open();
+
+// Allow overriding open().
+fs.ReadStream.prototype.open = common.mustCall();
+fs.createReadStream('asd');
diff --git a/test/parallel/test-fs-write-stream-patch-open.js b/test/parallel/test-fs-write-stream-patch-open.js
new file mode 100644
index 0000000000..1c82e80213
--- /dev/null
+++ b/test/parallel/test-fs-write-stream-patch-open.js
@@ -0,0 +1,34 @@
+'use strict';
+const common = require('../common');
+const fs = require('fs');
+
+const tmpdir = require('../common/tmpdir');
+
+// Run in a child process because 'out' is opened twice, blocking the tmpdir
+// and preventing cleanup.
+if (process.argv[2] !== 'child') {
+  // Parent
+  const assert = require('assert');
+  const { fork } = require('child_process');
+  tmpdir.refresh();
+
+  // Run test
+  const child = fork(__filename, ['child'], { stdio: 'inherit' });
+  child.on('exit', common.mustCall(function(code) {
+    assert.strictEqual(code, 0);
+  }));
+
+  return;
+}
+
+// Child
+
+common.expectWarning(
+  'DeprecationWarning',
+  'WriteStream.prototype.open() is deprecated', 'DEP0XXX');
+const s = fs.createWriteStream(`${tmpdir.path}/out`);
+s.open();
+
+// Allow overriding open().
+fs.WriteStream.prototype.open = common.mustCall();
+fs.createWriteStream('asd');