vfs: unflag

Enable node:vfs by default. --no-experimental-vfs disables node:vfs
exposure and --vfs-load.

Assisted-by: pi
Signed-off-by: Matteo Collina <hello@matteocollina.com>
PR-URL: https://github.com/nodejs/node/pull/66318
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Paolo Insogna <paolo@cowtech.it>

doc/api/cli.md

@@ -330,7 +330,7 @@ so mounting one is gated on its own flag rather than on `--allow-fs-read` or
 `--allow-fs-write`.
 
 ```console
-$ node --experimental-vfs --permission --allow-fs-vfs app.js
+$ node --permission --allow-fs-vfs app.js
 ```
 
 ### `--allow-fs-write`
@@ -1711,16 +1711,6 @@ with AND, so a test must satisfy every expression to run.
 A malformed expression causes the test runner to exit with a non-zero status
 before running any tests.
 
-### `--experimental-vfs`
-
-<!-- YAML
-added: v26.4.0
--->
-
-> Stability: 1 - Experimental
-
-Enable the experimental [`node:vfs`][] module.
-
 ### `--experimental-vm-modules`
 
 <!-- YAML
@@ -2364,6 +2354,18 @@ changes:
 
 Disable the experimental [`node:sqlite`][] module.
 
+### `--no-experimental-vfs`
+
+<!-- YAML
+added: v26.4.0
+changes:
+  - version: REPLACEME
+    pr-url: https://github.com/nodejs/node/pull/66318
+    description: VFS is unflagged but still experimental.
+-->
+
+Disable the experimental [`node:vfs`][] module and `--vfs-load`.
+
 ### `--no-experimental-webstorage`
 
 <!-- YAML
@@ -3907,11 +3909,13 @@ added: v26.10.0
 
 * `source` {string} A directory or an archive file to mount and run.
 
-Requires [`--experimental-vfs`][]. May be given at most once.
+May be given at most once.
 
 Mounts `source` as a virtual file system ([`node:vfs`][]), and runs the entry
 point and all subsequent `require()`/`import` resolution against that mount
-rather than the real file system. The mount is placed at a reserved mount point
+rather than the real file system. This option is unavailable when
+`--no-experimental-vfs` disables [`node:vfs`][]. The mount is placed at a
+reserved mount point
 assigned by Node.js, so it never shadows real paths and no target can be
 chosen. The entry point is taken from the mount the same way `node <directory>`
 takes one: the mount's own `package.json` `"main"`, or `index.js`. Any
@@ -3942,18 +3946,17 @@ same thing in all of them.
 
 A worker created with its own `execArgv` inherits none of the parent's options,
 and so does not mount the source at all. To run a script from the mount, such a
-worker must be given the same options again, `--experimental-vfs` and
-`--vfs-load`; without them, that thread has no mount for the script to come
-from, and the worker fails to load it. `--experimental-vfs` is also what makes
-[`node:vfs`][] available to the worker's own code. A worker whose script comes
-from anywhere else, such as the real file system, needs nothing added.
+worker must be given `--vfs-load` again; without it, that thread has no mount
+for the script to come from, and the worker fails to load it. [`node:vfs`][] is
+available to worker code without an experimental flag. A worker whose script
+comes from anywhere else, such as the real file system, needs nothing added.
 
 `--vfs-load` is not permitted in [`NODE_OPTIONS`][]: which entry point runs is
 the command line's decision, and the environment must not be able to redirect
 it.
 
 ```console
-$ node --experimental-vfs --vfs-load=app.zip
+$ node --vfs-load=app.zip
 ```
 
 ### `--watch`
@@ -4280,7 +4283,6 @@ one is included in the list below.
 * `--experimental-stream-iter`
 * `--experimental-test-isolation`
 * `--experimental-top-level-await`
-* `--experimental-vfs`
 * `--experimental-vm-modules`
 * `--experimental-wasi-unstable-preview1`
 * `--experimental-web-worker`
@@ -4315,6 +4317,7 @@ one is included in the list below.
 * `--no-experimental-global-navigator`
 * `--no-experimental-sqlite`
 * `--no-experimental-strip-types`
+* `--no-experimental-vfs`
 * `--no-experimental-webstorage`
 * `--no-extra-info-on-fatal-exception`
 * `--no-force-async-hooks-checks`
@@ -4914,7 +4917,6 @@ node --stack-trace-limit=12 -p -e "Error.stackTraceLimit" # prints 12
 [`--env-file-if-exists`]: #--env-file-if-existsfile
 [`--env-file`]: #--env-filefile
 [`--experimental-sea-config`]: single-executable-applications.md#1-generating-single-executable-preparation-blobs
-[`--experimental-vfs`]: #--experimental-vfs
 [`--heap-prof-dir`]: #--heap-prof-dir
 [`--import`]: #--importmodule
 [`--no-require-module`]: #--no-require-module

doc/api/vfs.md

@@ -24,8 +24,8 @@ import vfs from 'node:vfs';
 const vfs = require('node:vfs');
 ```
 
-This module is only available under the `node:` scheme, and only when Node.js
-is started with the `--experimental-vfs` flag.
+This module is only available under the `node:` scheme. Loading it emits an
+`ExperimentalWarning`.
 
 ## Security
 
@@ -77,8 +77,9 @@ added: v26.4.0
 * `provider` {VirtualProvider} The provider to use. **Default:**
   `new MemoryProvider()`.
 * `options` {Object}
-  * `emitExperimentalWarning` {boolean} Whether to emit the experimental
-    warning when the instance is created. **Default:** `true`.
+  * `emitExperimentalWarning` {boolean} Whether to emit an experimental warning
+    when an instance is created. **Default:** `true`. Loading `node:vfs` emits
+    the warning regardless of this option.
 * Returns: {VirtualFileSystem}
 
 Convenience factory equivalent to `new VirtualFileSystem(provider, options)`.
@@ -148,7 +149,7 @@ vfs.registerProvider({
 ```
 
 ```console
-$ node --experimental-vfs --require ./provider.js \
+$ node --require ./provider.js \
        --vfs-load archive.customfmt
 ```
 
@@ -193,8 +194,9 @@ added: v26.4.0
 * `provider` {VirtualProvider} The provider to use. **Default:**
   `new MemoryProvider()`.
 * `options` {Object}
-  * `emitExperimentalWarning` {boolean} Whether to emit the experimental
-    warning. **Default:** `true`.
+  * `emitExperimentalWarning` {boolean} Whether to emit an experimental warning
+    when an instance is created. **Default:** `true`. Loading `node:vfs` emits
+    the warning regardless of this option.
 
 ### `vfs.mount()`
 

doc/node.1

@@ -210,7 +210,7 @@ A mounted VFS serves paths that the file system permissions do not describe,
 so mounting one is gated on its own flag rather than on \fB--allow-fs-read\fR or
 \fB--allow-fs-write\fR.
 .Bd -literal
-$ node --experimental-vfs --permission --allow-fs-vfs app.js
+$ node --permission --allow-fs-vfs app.js
 .Ed
 .
 .It Fl -allow-fs-write
@@ -930,9 +930,6 @@ with AND, so a test must satisfy every expression to run.
 A malformed expression causes the test runner to exit with a non-zero status
 before running any tests.
 .
-.It Fl -experimental-vfs
-Enable the experimental \fBnode:vfs\fR module.
-.
 .It Fl -experimental-vm-modules
 Enable experimental ES Module support in the \fBnode:vm\fR module.
 .
@@ -1233,6 +1230,9 @@ Legacy alias for \fB--no-require-module\fR.
 .It Fl -no-experimental-sqlite
 Disable the experimental \fBnode:sqlite\fR module.
 .
+.It Fl -no-experimental-vfs
+Disable the experimental \fBnode:vfs\fR module and \fB--vfs-load\fR.
+.
 .It Fl -no-experimental-webstorage
 Disable \fBWeb Storage\fR support.
 .
@@ -1973,10 +1973,12 @@ Print node's version.
 .It
 \fBsource\fR \fB{string}\fR A directory or an archive file to mount and run.
 .El
-Requires \fB--experimental-vfs\fR. May be given at most once.
+May be given at most once.
 Mounts \fBsource\fR as a virtual file system (\fBnode:vfs\fR), and runs the entry
 point and all subsequent \fBrequire()\fR/\fBimport\fR resolution against that mount
-rather than the real file system. The mount is placed at a reserved mount point
+rather than the real file system. This option is unavailable when
+\fB--no-experimental-vfs\fR disables \fBnode:vfs\fR. The mount is placed at a
+reserved mount point
 assigned by Node.js, so it never shadows real paths and no target can be
 chosen. The entry point is taken from the mount the same way \fBnode <directory>\fR
 takes one: the mount's own \fBpackage.json\fR \fB"main"\fR, or \fBindex.js\fR. Any
@@ -2004,16 +2006,15 @@ mounts it, whatever else that thread mounts, so a path into the mount means the
 same thing in all of them.
 A worker created with its own \fBexecArgv\fR inherits none of the parent's options,
 and so does not mount the source at all. To run a script from the mount, such a
-worker must be given the same options again, \fB--experimental-vfs\fR and
-\fB--vfs-load\fR; without them, that thread has no mount for the script to come
-from, and the worker fails to load it. \fB--experimental-vfs\fR is also what makes
-\fBnode:vfs\fR available to the worker's own code. A worker whose script comes
-from anywhere else, such as the real file system, needs nothing added.
+worker must be given \fB--vfs-load\fR again; without it, that thread has no mount
+for the script to come from, and the worker fails to load it. \fBnode:vfs\fR is
+available to worker code without an experimental flag. A worker whose script
+comes from anywhere else, such as the real file system, needs nothing added.
 \fB--vfs-load\fR is not permitted in \fBNODE_OPTIONS\fR: which entry point runs is
 the command line's decision, and the environment must not be able to redirect
 it.
 .Bd -literal
-$ node --experimental-vfs --vfs-load=app.zip
+$ node --vfs-load=app.zip
 .Ed
 .
 .It Fl -watch
@@ -2271,8 +2272,6 @@ one is included in the list below.
 .It
 \fB--experimental-top-level-await\fR
 .It
-\fB--experimental-vfs\fR
-.It
 \fB--experimental-vm-modules\fR
 .It
 \fB--experimental-wasi-unstable-preview1\fR
@@ -2341,6 +2340,8 @@ one is included in the list below.
 .It
 \fB--no-experimental-strip-types\fR
 .It
+\fB--no-experimental-vfs\fR
+.It
 \fB--no-experimental-webstorage\fR
 .It
 \fB--no-extra-info-on-fatal-exception\fR

lib/internal/vfs/file_system.js

@@ -15,7 +15,6 @@ const {
     ERR_INVALID_STATE,
   },
 } = require('internal/errors');
-const { validateBoolean } = require('internal/validators');
 const { MemoryProvider } = require('internal/vfs/providers/memory');
 const path = require('path');
 const { posix: pathPosix, resolve: resolvePath, sep, toNamespacedPath } = path;
@@ -39,6 +38,7 @@ const {
 const { VirtualReadStream, VirtualWriteStream } = require('internal/vfs/streams');
 const { VirtualDir } = require('internal/vfs/dir');
 const { emitExperimentalWarning, kEmptyObject } = require('internal/util');
+const { validateBoolean } = require('internal/validators');
 let debug = require('internal/util/debuglog').debuglog('vfs', (fn) => {
   debug = fn;
 });
@@ -111,7 +111,6 @@ class VirtualFileSystem {
   /**
    * @param {VirtualProvider|object} [providerOrOptions] The provider to use, or options
    * @param {object} [options] Configuration options
-   * @param {boolean} [options.emitExperimentalWarning] Emit the experimental warning (default: true)
    */
   constructor(providerOrOptions, options = kEmptyObject) {
     let provider = null;

lib/vfs.js

@@ -4,6 +4,9 @@ const {
   FunctionPrototypeSymbolHasInstance,
 } = primordials;
 
+const { emitExperimentalWarning } = require('internal/util');
+emitExperimentalWarning('VirtualFileSystem');
+
 const { VirtualFileSystem } = require('internal/vfs/file_system');
 const { VirtualProvider } = require('internal/vfs/provider');
 const { MemoryProvider } = require('internal/vfs/providers/memory');

src/node.cc

@@ -1119,7 +1119,7 @@ static ExitCode InitializeNodeWithArgsInternal(
   {
     auto* env_options = per_process::cli_options->per_isolate->per_env.get();
     if (!env_options->experimental_vfs && env_options->vfs_load) {
-      errors->push_back("--vfs-load requires --experimental-vfs");
+      errors->push_back("--vfs-load requires node:vfs to be enabled");
     }
     // A second --vfs-load would silently replace the first, and the option
     // itself cannot say how often it was given; count it in the node options

src/node_options.cc

@@ -801,7 +801,8 @@ EnvironmentOptionsParser::EnvironmentOptionsParser() {
   AddOption("--experimental-vfs",
             "experimental node:vfs module",
             BOOL_FIELD(experimental_vfs),
-            kAllowedInEnvvar);
+            kAllowedInEnvvar,
+            true);
   // Choosing the entry point is the command line's alone: an environment
   // variable must not be able to redirect what a `node <args>` invocation runs,
   // so this is rejected in NODE_OPTIONS. The source and whether to run from it
@@ -810,7 +811,7 @@ EnvironmentOptionsParser::EnvironmentOptionsParser() {
   AddOption("--vfs-load",
             "mount a directory or archive as a virtual file system and run the "
             "entry point and module resolution against it instead of the real "
-            "file system (may be given once; requires --experimental-vfs)",
+            "file system (may be given once)",
             &EnvironmentOptions::vfs_load_source,
             kDisallowedInEnvvar);
   AddOption("[vfs_load_set]", "", BOOL_FIELD(vfs_load));

src/node_options.h

@@ -215,7 +215,7 @@ class EnvironmentOptions : public Options {
   DEFINE_BOOL_FIELD(experimental_websocket) = true;
   DEFINE_BOOL_FIELD(experimental_sqlite) = HAVE_SQLITE;
   DEFINE_BOOL_FIELD(experimental_stream_iter) = EXPERIMENTALS_DEFAULT_VALUE;
-  DEFINE_BOOL_FIELD(experimental_vfs) = EXPERIMENTALS_DEFAULT_VALUE;
+  DEFINE_BOOL_FIELD(experimental_vfs) = true;
   DEFINE_BOOL_FIELD(vfs_load) = false;
   DEFINE_BOOL_FIELD(webstorage) = HAVE_SQLITE;
   DEFINE_BOOL_FIELD(experimental_dtls) = EXPERIMENTALS_DEFAULT_VALUE;

test/ffi/test-ffi-vfs.js

@@ -1,4 +1,4 @@
-// Flags: --experimental-vfs
+// Flags: --disable-warning=ExperimentalWarning
 'use strict';
 const common = require('../common');
 common.skipIfFFIMissing();

test/parallel/test-module-builtin-experimental.js

@@ -1,3 +1,4 @@
+// Flags: --disable-warning=ExperimentalWarning
 'use strict';
 
 const common = require('../common');
@@ -8,7 +9,6 @@ const experimentalBuiltins = [
   ['bench/reporters', '--experimental-bench', true],
   ['dtls', '--experimental-dtls', common.hasDtls],
   ['quic', '--experimental-quic', common.hasQuic],
-  ['vfs', '--experimental-vfs', true],
 ].filter(([, , available]) => available);
 
 for (const [id, flag] of experimentalBuiltins) {
@@ -51,7 +51,14 @@ if (common.hasFFI) {
   ], { status: 0 });
 }
 
-const schemeOnlyBuiltins = ['node:test', 'node:sea'];
+// node:vfs is enabled by default and can be disabled with
+// --no-experimental-vfs.
+spawnSyncAndAssert(process.execPath, [
+  '--no-experimental-vfs',
+  '-e', `const m = require('node:module'); if (m.builtinModules.includes('node:vfs')) process.exit(1); try { require('node:vfs'); } catch (e) { if (e.code === 'ERR_UNKNOWN_BUILTIN_MODULE') process.exit(0); } process.exit(1);`,
+], { status: 0 });
+
+const schemeOnlyBuiltins = ['node:test', 'node:sea', 'node:vfs'];
 if (common.hasFFI) {
   schemeOnlyBuiltins.push('node:ffi');
 }

test/parallel/test-permission-dlopen-binary.js

@@ -92,7 +92,7 @@ function run(...permissions) {
   `;
   const vfsRun = (...permissions) => spawnSync(
     process.execPath,
-    ['--experimental-vfs', '--permission', '--allow-fs-read=*',
+    ['--permission', '--allow-fs-read=*',
      ...permissions, '-e', mounted],
     { encoding: 'utf8' });
 

test/parallel/test-require-resolve.js

@@ -62,8 +62,6 @@ require(fixtures.path('resolve-paths', 'default', 'verify-paths.js'));
   builtinModules.forEach((mod) => {
     // TODO(@jasnell): Remove once node:quic is no longer flagged
     if (mod === 'node:quic') return;
-    // Remove once node:vfs is no longer flagged
-    if (mod === 'node:vfs') return;
     if (mod === 'node:sqlite' && !common.hasSQLite) return;
     assert.strictEqual(require.resolve.paths(mod), null);
     if (!mod.startsWith('node:')) {

test/parallel/test-vfs-access-modes.js

@@ -1,4 +1,4 @@
-// Flags: --experimental-vfs
+// Flags: --disable-warning=ExperimentalWarning
 'use strict';
 
 // access / accessSync honour the R_OK / W_OK / X_OK / F_OK mode bits and

test/parallel/test-vfs-addon.js

@@ -1,4 +1,4 @@
-// Flags: --experimental-vfs
+// Flags: --disable-warning=ExperimentalWarning
 'use strict';
 const common = require('../common');
 const assert = require('assert');

test/parallel/test-vfs-append-write.js

@@ -1,4 +1,4 @@
-// Flags: --experimental-vfs
+// Flags: --disable-warning=ExperimentalWarning
 'use strict';
 
 // writeSync in append mode must append, not overwrite.

test/parallel/test-vfs-bigint-position.js

@@ -1,4 +1,4 @@
-// Flags: --experimental-vfs
+// Flags: --disable-warning=ExperimentalWarning
 'use strict';
 
 // VFS readSync should accept a BigInt position parameter.

test/parallel/test-vfs-callback-api.js

@@ -1,4 +1,4 @@
-// Flags: --experimental-vfs
+// Flags: --disable-warning=ExperimentalWarning
 'use strict';
 
 // Exercise the VFS callback-style async API on every method.

test/parallel/test-vfs-copyfile-mode.js

@@ -1,4 +1,4 @@
-// Flags: --experimental-vfs
+// Flags: --disable-warning=ExperimentalWarning
 'use strict';
 
 // Tests for VFS copyFile mode support:

test/parallel/test-vfs-create.js

@@ -1,7 +1,7 @@
-// Flags: --experimental-vfs
+// Flags: --disable-warning=ExperimentalWarning
 'use strict';
 
-// Constructor variants and option validation for vfs.create() and
+// Constructor variants for vfs.create() and
 // `new VirtualFileSystem(...)`.
 
 require('../common');
@@ -14,10 +14,9 @@ const vfs = require('node:vfs');
   assert.ok(myVfs.provider instanceof vfs.MemoryProvider);
 }
 
-// vfs.create with first arg as options object (no provider)
+// vfs.create with the options object as its first argument
 {
   const myVfs = vfs.create({ emitExperimentalWarning: false });
-  assert.ok(myVfs);
   assert.ok(myVfs.provider instanceof vfs.MemoryProvider);
 }
 
@@ -28,7 +27,7 @@ const vfs = require('node:vfs');
   assert.strictEqual(myVfs.provider, provider);
 }
 
-// new VirtualFileSystem(options) directly
+// new VirtualFileSystem() directly
 {
   const myVfs = new vfs.VirtualFileSystem({ emitExperimentalWarning: false });
   assert.ok(myVfs);

test/parallel/test-vfs-ctime-update.js

@@ -1,4 +1,4 @@
-// Flags: --experimental-vfs
+// Flags: --disable-warning=ExperimentalWarning
 'use strict';
 
 require('../common');

test/parallel/test-vfs-destructuring.js

@@ -1,4 +1,4 @@
-// Flags: --experimental-vfs
+// Flags: --disable-warning=ExperimentalWarning
 'use strict';
 
 const common = require('../common');

test/parallel/test-vfs-dir-handle.js

@@ -1,4 +1,4 @@
-// Flags: --experimental-vfs
+// Flags: --disable-warning=ExperimentalWarning
 'use strict';
 
 // Exercise the VirtualDir handle returned by opendirSync.

test/parallel/test-vfs-fd.js

@@ -1,4 +1,4 @@
-// Flags: --experimental-vfs
+// Flags: --disable-warning=ExperimentalWarning
 'use strict';
 
 const common = require('../common');

test/parallel/test-vfs-file-handle.js

@@ -1,4 +1,4 @@
-// Flags: --experimental-vfs
+// Flags: --disable-warning=ExperimentalWarning
 'use strict';
 
 // Exercise VirtualFileHandle / MemoryFileHandle methods directly via

test/parallel/test-vfs-flag.js

@@ -1,59 +1,54 @@
 'use strict';
 
-// node:vfs is gated behind --experimental-vfs. Without the flag the
-// module is not exposed; bare `vfs` (without the node: scheme) is also
-// blocked.
+// node:vfs is available without an experimental flag. The old positive flag
+// remains accepted for compatibility, and --no-experimental-vfs disables it.
 
 require('../common');
 const { spawnSyncAndAssert } = require('../common/child_process');
 
-// Without the flag, requiring node:vfs throws ERR_UNKNOWN_BUILTIN_MODULE.
-{
-  spawnSyncAndAssert(process.execPath, [
-    '-e', 'require("node:vfs")',
-  ], { status: 1, stderr: /ERR_UNKNOWN_BUILTIN_MODULE/ });
-}
-
-// Without the flag, importing node:vfs throws ERR_UNKNOWN_BUILTIN_MODULE.
-{
-  spawnSyncAndAssert(process.execPath, [
-    '--input-type=module',
-    '-e', 'import("node:vfs").catch((e) => { console.error(e.code); process.exit(1); });',
-  ], {
-    status: 1,
-    stderr: /ERR_UNKNOWN_BUILTIN_MODULE/,
-  });
-}
-
-// With the flag, node:vfs loads and works.
+// CommonJS and ESM can load node:vfs without a flag.
 {
   const script =
     'const v = require("node:vfs");' +
     'const x = v.create();' +
     'x.writeFileSync("/x", "hi");' +
     'console.log(x.readFileSync("/x", "utf8"));';
-  spawnSyncAndAssert(process.execPath, ['--experimental-vfs', '-e', script], {
+  spawnSyncAndAssert(process.execPath, ['-e', script], {
     stdout: 'hi',
+    stderr: /ExperimentalWarning: VirtualFileSystem is an experimental feature/,
     trim: true,
   });
+
+  spawnSyncAndAssert(process.execPath, [
+    '--input-type=module',
+    '-e', 'import("node:vfs").then(({ default: v }) => console.log(typeof v.create));',
+  ], {
+    stdout: 'function\n',
+    stderr: /ExperimentalWarning: VirtualFileSystem is an experimental feature/,
+  });
 }
 
-// Bare `vfs` (no node: scheme) is always blocked.
-{
-  spawnSyncAndAssert(process.execPath, [
-    '--experimental-vfs',
-    '-e', "require('vfs')",
-  ], { status: 1, stderr: /Cannot find module 'vfs'/ });
-}
+// The old positive flag is accepted for compatibility but no longer gates the
+// module.
+spawnSyncAndAssert(process.execPath, [
+  '--experimental-vfs',
+  '-p',
+  'require("node:module").builtinModules.includes("node:vfs")',
+], { stdout: 'true\n', stderr: '' });
 
-// Module.builtinModules reflects whether --experimental-vfs is active.
-for (const [flag, expected] of [
-  ['--experimental-vfs', 'true\n'],
-  ['--no-experimental-vfs', 'false\n'],
-]) {
-  spawnSyncAndAssert(process.execPath, [
-    flag,
-    '-p',
-    'require("node:module").builtinModules.includes("node:vfs")',
-  ], { stdout: expected, stderr: '' });
-}
+// --no-experimental-vfs disables node:vfs.
+spawnSyncAndAssert(process.execPath, [
+  '--no-experimental-vfs',
+  '-p',
+  'require("node:module").builtinModules.includes("node:vfs")',
+], { stdout: 'false\n', stderr: '' });
+
+spawnSyncAndAssert(process.execPath, [
+  '--no-experimental-vfs',
+  '-e', 'require("node:vfs")',
+], { status: 1, stderr: /ERR_UNKNOWN_BUILTIN_MODULE/ });
+
+// Bare `vfs` (no node: scheme) remains unavailable.
+spawnSyncAndAssert(process.execPath, [
+  '-e', "require('vfs')",
+], { status: 1, stderr: /Cannot find module 'vfs'/ });

test/parallel/test-vfs-fs-accessSync.js

@@ -1,4 +1,4 @@
-// Flags: --experimental-vfs
+// Flags: --disable-warning=ExperimentalWarning
 'use strict';
 
 // fs.accessSync dispatches to VFS; missing paths throw ENOENT.

test/parallel/test-vfs-fs-callback-error-paths.js

@@ -1,4 +1,4 @@
-// Flags: --experimental-vfs
+// Flags: --disable-warning=ExperimentalWarning
 'use strict';
 
 // VFS dispatch on the async callback fs methods must surface provider errors

test/parallel/test-vfs-fs-chmod-callback.js

@@ -1,4 +1,4 @@
-// Flags: --experimental-vfs
+// Flags: --disable-warning=ExperimentalWarning
 'use strict';
 
 // fs.chmod, fs.chown, fs.lchown, fs.utimes, and fs.lutimes callbacks dispatch

test/parallel/test-vfs-fs-chmodSync.js

@@ -1,4 +1,4 @@
-// Flags: --experimental-vfs
+// Flags: --disable-warning=ExperimentalWarning
 'use strict';
 
 // fs.chmodSync, fs.chownSync, fs.lchownSync, fs.utimesSync, and

test/parallel/test-vfs-fs-copyFileSync.js

@@ -1,4 +1,4 @@
-// Flags: --experimental-vfs
+// Flags: --disable-warning=ExperimentalWarning
 'use strict';
 
 // fs.copyFileSync dispatches to VFS when both paths are within the same mount.

test/parallel/test-vfs-fs-createReadStream.js

@@ -1,4 +1,4 @@
-// Flags: --experimental-vfs
+// Flags: --disable-warning=ExperimentalWarning
 'use strict';
 
 // fs.createReadStream dispatches through VFS, including the emitted 'open'

test/parallel/test-vfs-fs-createWriteStream.js

@@ -1,4 +1,4 @@
-// Flags: --experimental-vfs
+// Flags: --disable-warning=ExperimentalWarning
 'use strict';
 
 // fs.createWriteStream dispatches through VFS, exposes a `path` property and

test/parallel/test-vfs-fs-existsSync.js

@@ -1,4 +1,4 @@
-// Flags: --experimental-vfs
+// Flags: --disable-warning=ExperimentalWarning
 'use strict';
 
 // fs.existsSync dispatches to VFS for paths under a mount.

test/parallel/test-vfs-fs-fchmod-callback.js

@@ -1,4 +1,4 @@
-// Flags: --experimental-vfs
+// Flags: --disable-warning=ExperimentalWarning
 'use strict';
 
 // fs.fchmod, fs.fchown, fs.futimes, fs.fdatasync, and fs.fsync callbacks

test/parallel/test-vfs-fs-linkSync.js

@@ -1,4 +1,4 @@
-// Flags: --experimental-vfs
+// Flags: --disable-warning=ExperimentalWarning
 'use strict';
 
 // fs.linkSync dispatches to VFS for hard links within the same mount.

test/parallel/test-vfs-fs-matches-real-fs.js

@@ -1,4 +1,4 @@
-// Flags: --experimental-vfs
+// Flags: --disable-warning=ExperimentalWarning
 'use strict';
 
 // `node:fs` entry points route mounted paths through the VFS hooks. Where a

test/parallel/test-vfs-fs-mkdir-callback.js

@@ -1,4 +1,4 @@
-// Flags: --experimental-vfs
+// Flags: --disable-warning=ExperimentalWarning
 'use strict';
 
 // fs.mkdir, fs.rmdir, fs.rm, and fs.unlink callbacks dispatch through VFS.

test/parallel/test-vfs-fs-mkdirSync.js

@@ -1,4 +1,4 @@
-// Flags: --experimental-vfs
+// Flags: --disable-warning=ExperimentalWarning
 'use strict';
 
 // fs.mkdirSync dispatches to VFS, including the `recursive: true` form.

test/parallel/test-vfs-fs-mkdtempSync.js

@@ -1,4 +1,4 @@
-// Flags: --experimental-vfs
+// Flags: --disable-warning=ExperimentalWarning
 'use strict';
 
 // fs.mkdtempSync dispatches to VFS and returns a mount-rooted path, including

test/parallel/test-vfs-fs-open-callback.js

@@ -1,4 +1,4 @@
-// Flags: --experimental-vfs
+// Flags: --disable-warning=ExperimentalWarning
 'use strict';
 
 // fs.open / fs.fstat / fs.read / fs.write / fs.close / fs.ftruncate callbacks

test/parallel/test-vfs-fs-openAsBlob.js

@@ -1,4 +1,4 @@
-// Flags: --experimental-vfs
+// Flags: --disable-warning=ExperimentalWarning
 'use strict';
 
 // fs.openAsBlob and fs.openAsBlobSync dispatch to VFS and return Blobs over the virtual file.

test/parallel/test-vfs-fs-openSync.js

@@ -1,4 +1,4 @@
-// Flags: --experimental-vfs
+// Flags: --disable-warning=ExperimentalWarning
 'use strict';
 
 // fs.openSync / fs.readSync / fs.writeSync / fs.fstatSync / fs.closeSync /

test/parallel/test-vfs-fs-opendir-callback.js

@@ -1,4 +1,4 @@
-// Flags: --experimental-vfs
+// Flags: --disable-warning=ExperimentalWarning
 'use strict';
 
 // fs.opendir callback dispatches through VFS, both via readSync() iteration

test/parallel/test-vfs-fs-opendirSync.js

@@ -1,4 +1,4 @@
-// Flags: --experimental-vfs
+// Flags: --disable-warning=ExperimentalWarning
 'use strict';
 
 // fs.opendirSync dispatches to VFS and returns a Dir-like iterable.

test/parallel/test-vfs-fs-promises-buffer-encoding.js

@@ -1,4 +1,4 @@
-// Flags: --experimental-vfs
+// Flags: --disable-warning=ExperimentalWarning
 'use strict';
 
 // The promise-based fs methods that accept `encoding: 'buffer'` must convert

test/parallel/test-vfs-fs-promises-stat-no-throw.js

@@ -1,4 +1,4 @@
-// Flags: --experimental-vfs
+// Flags: --disable-warning=ExperimentalWarning
 'use strict';
 
 // fsp.stat() with throwIfNoEntry: false on a missing path within a mount

test/parallel/test-vfs-fs-promises.js

@@ -1,4 +1,4 @@
-// Flags: --experimental-vfs
+// Flags: --disable-warning=ExperimentalWarning
 'use strict';
 
 // fs/promises dispatches through VFS for each supported path-based and

test/parallel/test-vfs-fs-readFile-callback.js

@@ -1,4 +1,4 @@
-// Flags: --experimental-vfs
+// Flags: --disable-warning=ExperimentalWarning
 'use strict';
 
 // fs.readFile, fs.readdir, fs.realpath, fs.access, and fs.exists callbacks

test/parallel/test-vfs-fs-readFileSync.js

@@ -1,4 +1,4 @@
-// Flags: --experimental-vfs
+// Flags: --disable-warning=ExperimentalWarning
 'use strict';
 
 // fs.readFileSync dispatches to VFS for both string paths and VFS-owned fds.

test/parallel/test-vfs-fs-readdirSync.js

@@ -1,4 +1,4 @@
-// Flags: --experimental-vfs
+// Flags: --disable-warning=ExperimentalWarning
 'use strict';
 
 // fs.readdirSync dispatches to VFS, including the buffer-encoding and

test/parallel/test-vfs-fs-realpathSync.js

@@ -1,4 +1,4 @@
-// Flags: --experimental-vfs
+// Flags: --disable-warning=ExperimentalWarning
 'use strict';
 
 // fs.realpathSync dispatches to VFS and returns a mount-rooted absolute path.

test/parallel/test-vfs-fs-rename-callback.js

@@ -1,4 +1,4 @@
-// Flags: --experimental-vfs
+// Flags: --disable-warning=ExperimentalWarning
 'use strict';
 
 // fs.rename and fs.copyFile callbacks dispatch through VFS.

test/parallel/test-vfs-fs-renameSync.js

@@ -1,4 +1,4 @@
-// Flags: --experimental-vfs
+// Flags: --disable-warning=ExperimentalWarning
 'use strict';
 
 // fs.renameSync dispatches to VFS when both paths are within the same mount.

test/parallel/test-vfs-fs-rmSync.js

@@ -1,4 +1,4 @@
-// Flags: --experimental-vfs
+// Flags: --disable-warning=ExperimentalWarning
 'use strict';
 
 // fs.rmSync, fs.rmdirSync, and fs.unlinkSync dispatch to VFS.

test/parallel/test-vfs-fs-stat-callback.js

@@ -1,4 +1,4 @@
-// Flags: --experimental-vfs
+// Flags: --disable-warning=ExperimentalWarning
 'use strict';
 
 // fs.stat and fs.lstat callbacks dispatch through VFS.

test/parallel/test-vfs-fs-statSync.js

@@ -1,4 +1,4 @@
-// Flags: --experimental-vfs
+// Flags: --disable-warning=ExperimentalWarning
 'use strict';
 
 // fs.statSync / fs.lstatSync / fs.statfsSync dispatch through the VFS layer,

test/parallel/test-vfs-fs-symlink-callback.js

@@ -1,4 +1,4 @@
-// Flags: --experimental-vfs
+// Flags: --disable-warning=ExperimentalWarning
 'use strict';
 
 // fs.symlink and fs.readlink callbacks dispatch through VFS.

test/parallel/test-vfs-fs-symlinkSync.js

@@ -1,4 +1,4 @@
-// Flags: --experimental-vfs
+// Flags: --disable-warning=ExperimentalWarning
 'use strict';
 
 // fs.symlinkSync and fs.readlinkSync dispatch through VFS, including the

test/parallel/test-vfs-fs-truncate-callback.js

@@ -1,4 +1,4 @@
-// Flags: --experimental-vfs
+// Flags: --disable-warning=ExperimentalWarning
 'use strict';
 
 // fs.truncate, fs.link, and fs.mkdtemp callbacks dispatch through VFS.

test/parallel/test-vfs-fs-truncateSync.js

@@ -1,4 +1,4 @@
-// Flags: --experimental-vfs
+// Flags: --disable-warning=ExperimentalWarning
 'use strict';
 
 // fs.truncateSync dispatches to VFS and shrinks the file content.

test/parallel/test-vfs-fs-watch-dispatch.js

@@ -1,4 +1,4 @@
-// Flags: --experimental-vfs
+// Flags: --disable-warning=ExperimentalWarning
 'use strict';
 
 // fs.watch on a path under a mount returns the provider's watcher object

test/parallel/test-vfs-fs-writeFile-callback.js

@@ -1,4 +1,4 @@
-// Flags: --experimental-vfs
+// Flags: --disable-warning=ExperimentalWarning
 'use strict';
 
 // fs.writeFile and fs.appendFile callbacks dispatch through VFS.

test/parallel/test-vfs-fs-writeFileSync.js

@@ -1,4 +1,4 @@
-// Flags: --experimental-vfs
+// Flags: --disable-warning=ExperimentalWarning
 'use strict';
 
 // fs.writeFileSync and fs.appendFileSync dispatch to VFS.

test/parallel/test-vfs-handle-semantics.js

@@ -1,4 +1,4 @@
-// Flags: --experimental-vfs
+// Flags: --disable-warning=ExperimentalWarning
 'use strict';
 
 // A file handle on a mounted path must answer the same `node:fs` calls the

test/parallel/test-vfs-hardlink-nlink.js

@@ -1,4 +1,4 @@
-// Flags: --experimental-vfs
+// Flags: --disable-warning=ExperimentalWarning
 'use strict';
 
 // Test that nlink count is updated correctly when creating/removing hard links.

test/parallel/test-vfs-import.mjs

@@ -1,4 +1,4 @@
-// Flags: --experimental-vfs
+// Flags: --disable-warning=ExperimentalWarning
 import '../common/index.mjs';
 import assert from 'assert';
 import { pathToFileURL } from 'node:url';

test/parallel/test-vfs-invalid-package-json.js

@@ -1,4 +1,4 @@
-// Flags: --experimental-vfs --expose-internals
+// Flags: --disable-warning=ExperimentalWarning --expose-internals
 'use strict';
 
 const common = require('../common');

test/parallel/test-vfs-layer-tag-prefix.mjs

@@ -1,4 +1,4 @@
-// Flags: --experimental-vfs
+// Flags: --disable-warning=ExperimentalWarning
 
 // Regression: unmounting a layer whose id is a decimal prefix of another
 // (e.g. layer 1 vs layer 10) must not purge the other's ESM cache entries.

test/parallel/test-vfs-lchown-symlink.js

@@ -1,4 +1,4 @@
-// Flags: --experimental-vfs
+// Flags: --disable-warning=ExperimentalWarning
 'use strict';
 
 const common = require('../common');

test/parallel/test-vfs-link.js

@@ -1,4 +1,4 @@
-// Flags: --experimental-vfs
+// Flags: --disable-warning=ExperimentalWarning
 'use strict';
 
 // Hard-link error cases: creating a link to a directory or to an

test/parallel/test-vfs-load.js

@@ -22,7 +22,7 @@ let id = 0;
 function fixture(name) { return path.join(tmpdir.path, `${id++}-${name}`); }
 
 function run(args) {
-  return spawnSync(process.execPath, ['--experimental-vfs', ...args], { encoding: 'utf8' });
+  return spawnSync(process.execPath, args, { encoding: 'utf8' });
 }
 
 // Node.js can be built without NODE_OPTIONS support, in which case the
@@ -49,6 +49,15 @@ function envArg(flag, value) {
   assert.match(res.stdout, /hello from inside the mount/);
 }
 
+// --no-experimental-vfs disables --vfs-load.
+{
+  const dir = fixture('disabled');
+  fs.mkdirSync(dir, { recursive: true });
+  const res = run(['--no-experimental-vfs', `--vfs-load=${dir}`]);
+  assert.notStrictEqual(res.status, 0);
+  assert.match(res.stderr, /--vfs-load requires node:vfs to be enabled/);
+}
+
 // A provider registered by a -r (CommonJS) preload backs a custom file format.
 {
   const providerModule = fixture('provider.js');
@@ -198,7 +207,7 @@ parentPort.postMessage('hello from esm worker in mount');
 const path = require('path');
 const { Worker } = require('worker_threads');
 const w = new Worker(path.join(__dirname, 'worker.js'), {
-  execArgv: ['--experimental-vfs', '--vfs-load=' + process.argv[1]],
+  execArgv: ['--vfs-load=' + process.argv[1]],
 });
 w.on('message', (m) => { console.log(m); process.exit(0); });
 w.on('error', (e) => { console.error(e); process.exit(1); });
@@ -308,8 +317,7 @@ if (hasNodeOptions) {
 
   // On its own, and alongside a --vfs-load the command line legitimately gave:
   // the environment is refused either way rather than merged.
-  for (const args of [['--experimental-vfs'],
-                      ['--experimental-vfs', `--vfs-load=${dir}`]]) {
+  for (const args of [[], [`--vfs-load=${dir}`]]) {
     const res = spawnSync(process.execPath, args, {
       encoding: 'utf8',
       env: { ...process.env, NODE_OPTIONS: envArg('--vfs-load', dir) },
@@ -319,10 +327,8 @@ if (hasNodeOptions) {
   }
 }
 
-// --experimental-vfs and --vfs-load may arrive from different places: the
-// options are validated once every source has been parsed, so a --vfs-load on
-// the command line is not rejected for an --experimental-vfs that only
-// NODE_OPTIONS carries.
+// The old --experimental-vfs option remains accepted in NODE_OPTIONS. Its
+// positive form no longer gates --vfs-load, and its negated form disables it.
 if (hasNodeOptions) {
   const dir = fixture('env-flag-cli-load');
   fs.mkdirSync(dir, { recursive: true });
@@ -334,6 +340,13 @@ if (hasNodeOptions) {
   });
   assert.strictEqual(res.status, 0, res.stderr);
   assert.match(res.stdout, /ran/);
+
+  const disabled = spawnSync(process.execPath, [`--vfs-load=${dir}`], {
+    encoding: 'utf8',
+    env: { ...process.env, NODE_OPTIONS: '--no-experimental-vfs' },
+  });
+  assert.notStrictEqual(disabled.status, 0);
+  assert.match(disabled.stderr, /--vfs-load requires node:vfs to be enabled/);
 }
 
 // Under --vfs-load the entry point comes from the mount, so no positional

test/parallel/test-vfs-memory-file-handle.js

@@ -1,4 +1,4 @@
-// Flags: --experimental-vfs --expose-internals
+// Flags: --disable-warning=ExperimentalWarning --expose-internals
 'use strict';
 
 // MemoryFileHandle internals: the "stats not available" path when there

test/parallel/test-vfs-memory-provider-dynamic.js

@@ -1,4 +1,4 @@
-// Flags: --experimental-vfs --expose-internals
+// Flags: --disable-warning=ExperimentalWarning --expose-internals
 'use strict';
 
 // MemoryProvider supports dynamic content providers and lazily-populated

test/parallel/test-vfs-memory-provider-flags.js

@@ -1,4 +1,4 @@
-// Flags: --experimental-vfs
+// Flags: --disable-warning=ExperimentalWarning
 'use strict';
 
 // MemoryProvider: numeric open flags (mirroring fs.constants.O_*) must be

test/parallel/test-vfs-memory-provider.js

@@ -1,4 +1,4 @@
-// Flags: --experimental-vfs --expose-internals
+// Flags: --disable-warning=ExperimentalWarning --expose-internals
 'use strict';
 
 const common = require('../common');

test/parallel/test-vfs-mkdir.js

@@ -1,4 +1,4 @@
-// Flags: --experimental-vfs
+// Flags: --disable-warning=ExperimentalWarning
 'use strict';
 
 // mkdirSync / rmdirSync behaviour: return value, recursive option, mode

test/parallel/test-vfs-mkdtemp.js

@@ -1,4 +1,4 @@
-// Flags: --experimental-vfs
+// Flags: --disable-warning=ExperimentalWarning
 'use strict';
 
 // mkdtemp / mkdtempSync behaviour.

test/parallel/test-vfs-module-hooks-cleanup.js

@@ -1,4 +1,4 @@
-// Flags: --experimental-vfs
+// Flags: --disable-warning=ExperimentalWarning
 'use strict';
 
 const common = require('../common');

test/parallel/test-vfs-module-hooks.mjs

@@ -1,4 +1,4 @@
-// Flags: --experimental-vfs
+// Flags: --disable-warning=ExperimentalWarning
 import '../common/index.mjs';
 import assert from 'assert';
 import { createRequire } from 'module';

test/parallel/test-vfs-module-paths.js

@@ -1,4 +1,4 @@
-// Flags: --experimental-vfs
+// Flags: --disable-warning=ExperimentalWarning
 'use strict';
 
 // The `node_modules` lookup for modules inside a mounted VFS stops at the
@@ -91,7 +91,7 @@ const tmpdir = require('../common/tmpdir');
   fs.writeFileSync(path.join(globalDir, 'gdep', 'index.js'),
                    'module.exports = "from-node-path";');
 
-  const out = execFileSync(process.execPath, ['--experimental-vfs', '-e', `
+  const out = execFileSync(process.execPath, ['-e', `
     const vfs = require('node:vfs');
     const path = require('path');
     const myVfs = vfs.create();

test/parallel/test-vfs-mount-errors.js

@@ -1,4 +1,4 @@
-// Flags: --experimental-vfs --expose-internals
+// Flags: --disable-warning=ExperimentalWarning --expose-internals
 'use strict';
 
 // Error paths in the VFS mount layer:

test/parallel/test-vfs-mount-point-url.js

@@ -1,4 +1,4 @@
-// Flags: --experimental-vfs
+// Flags: --disable-warning=ExperimentalWarning
 'use strict';
 
 require('../common');

test/parallel/test-vfs-mount.js

@@ -1,4 +1,4 @@
-// Flags: --experimental-vfs
+// Flags: --disable-warning=ExperimentalWarning
 'use strict';
 
 const common = require('../common');

test/parallel/test-vfs-multi-mount.js

@@ -1,4 +1,4 @@
-// Flags: --experimental-vfs
+// Flags: --disable-warning=ExperimentalWarning
 'use strict';
 
 // Two concurrent mounts must each route to its own VFS without

test/parallel/test-vfs-package-json-cache.js

@@ -1,4 +1,4 @@
-// Flags: --experimental-vfs
+// Flags: --disable-warning=ExperimentalWarning
 'use strict';
 
 // Package.json caches must be cleared on VFS unmount.

test/parallel/test-vfs-package-json.js

@@ -1,4 +1,4 @@
-// Flags: --experimental-vfs --expose-internals
+// Flags: --disable-warning=ExperimentalWarning --expose-internals
 'use strict';
 
 require('../common');

test/parallel/test-vfs-parent-timestamps.js

@@ -1,4 +1,4 @@
-// Flags: --experimental-vfs
+// Flags: --disable-warning=ExperimentalWarning
 'use strict';
 
 // Operations that modify a directory should bump its mtime/ctime.

test/parallel/test-vfs-promises-open.js

@@ -1,4 +1,4 @@
-// Flags: --experimental-vfs
+// Flags: --disable-warning=ExperimentalWarning
 'use strict';
 
 // VFS promises.open returns a usable handle.

test/parallel/test-vfs-promises.js

@@ -1,4 +1,4 @@
-// Flags: --experimental-vfs --expose-internals
+// Flags: --disable-warning=ExperimentalWarning --expose-internals
 'use strict';
 
 const common = require('../common');

test/parallel/test-vfs-readdir-symlink-recursive.js

@@ -1,4 +1,4 @@
-// Flags: --experimental-vfs
+// Flags: --disable-warning=ExperimentalWarning
 'use strict';
 
 // Recursive readdir must follow symlinks to directories.

test/parallel/test-vfs-readfile-async.js

@@ -1,4 +1,4 @@
-// Flags: --experimental-vfs
+// Flags: --disable-warning=ExperimentalWarning
 'use strict';
 
 // VFS readFile callback API.

test/parallel/test-vfs-readfile-encoding.js

@@ -1,4 +1,4 @@
-// Flags: --experimental-vfs
+// Flags: --disable-warning=ExperimentalWarning
 'use strict';
 
 // readFileSync with invalid encoding must throw.

test/parallel/test-vfs-readfile-flag.js

@@ -1,4 +1,4 @@
-// Flags: --experimental-vfs
+// Flags: --disable-warning=ExperimentalWarning
 'use strict';
 
 const common = require('../common');

test/parallel/test-vfs-real-provider-handle.js

@@ -1,4 +1,4 @@
-// Flags: --experimental-vfs --expose-internals
+// Flags: --disable-warning=ExperimentalWarning --expose-internals
 'use strict';
 
 // RealFileHandle: sync and async file-handle operations, plus EBADF

test/parallel/test-vfs-real-provider-promises.js

@@ -1,4 +1,4 @@
-// Flags: --experimental-vfs
+// Flags: --disable-warning=ExperimentalWarning
 'use strict';
 
 // Promises API for RealFSProvider: every async/promises method,

test/parallel/test-vfs-real-provider-symlinks.js

@@ -1,4 +1,4 @@
-// Flags: --experimental-vfs
+// Flags: --disable-warning=ExperimentalWarning
 'use strict';
 
 // Symlink and path-escape behaviour for RealFSProvider.

test/parallel/test-vfs-real-provider-watch.js

@@ -1,4 +1,4 @@
-// Flags: --experimental-vfs
+// Flags: --disable-warning=ExperimentalWarning
 'use strict';
 
 // watch / promises.watch / watchFile through RealFSProvider.

test/parallel/test-vfs-real-provider.js

@@ -1,4 +1,4 @@
-// Flags: --experimental-vfs
+// Flags: --disable-warning=ExperimentalWarning
 'use strict';
 
 // Synchronous API for RealFSProvider: construction, basic file ops,

test/parallel/test-vfs-rename-symlink-descendant.js

@@ -1,4 +1,4 @@
-// Flags: --experimental-vfs
+// Flags: --disable-warning=ExperimentalWarning
 'use strict';
 
 const common = require('../common');

test/parallel/test-vfs-rename.js

@@ -1,4 +1,4 @@
-// Flags: --experimental-vfs
+// Flags: --disable-warning=ExperimentalWarning
 'use strict';
 
 // Rename behaviour: overwrite, type mismatches, same-parent rename.