From 9584dbc29410ca4bc1ac2102a50c910ea26ebd0d Mon Sep 17 00:00:00 2001
From: sosoba <slawomir.osoba@coig.pl>
Date: Mon, 24 Apr 2023 07:36:14 +0200
Subject: [PATCH 01/16] Null-proofing

---
 lib/internal/watch_mode/files_watcher.js | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/lib/internal/watch_mode/files_watcher.js b/lib/internal/watch_mode/files_watcher.js
index 3c756c4b5d77c9..1a622f856aee64 100644
--- a/lib/internal/watch_mode/files_watcher.js
+++ b/lib/internal/watch_mode/files_watcher.js
@@ -90,8 +90,11 @@ class FilesWatcher extends EventEmitter {
       return;
     }
     const watcher = watch(path, { recursive });
-    watcher.on('change', (eventType, fileName) => this
-      .#onChange(recursive ? resolve(path, fileName) : path));
+    watcher.on('change', (eventType, fileName) => {
+      if (fileName !== null) {
+        this.#onChange(recursive ? resolve(path, fileName) : path);
+      }
+   });
     this.#watchers.set(path, { handle: watcher, recursive });
     if (recursive) {
       this.#removeWatchedChildren(path);

From 2e1e2d205df8d2cc943868d9bf35365bbf9732f8 Mon Sep 17 00:00:00 2001
From: sosoba <slawomir.osoba@coig.pl>
Date: Mon, 24 Apr 2023 09:04:49 +0200
Subject: [PATCH 02/16] Update fs.md

Wath can pass null as filename
---
 doc/api/fs.md | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/doc/api/fs.md b/doc/api/fs.md
index 0623e1c5a9dacf..c82c18ca603f54 100644
--- a/doc/api/fs.md
+++ b/doc/api/fs.md
@@ -1667,7 +1667,7 @@ added:
     should stop.
 * Returns: {AsyncIterator} of objects with the properties:
   * `eventType` {string} The type of change
-  * `filename` {string|Buffer} The name of the file changed.
+  * `filename` {string|Buffer|null} The name of the file changed.
 
 Returns an async iterator that watches for changes on `filename`, where `filename`
 is either a file or a directory.
@@ -4282,8 +4282,8 @@ same directory:
 ```bash
 $ tree .
 .
-├── mew
-└── mewtwo -> ./mew
++¦¦ mew
+L¦¦ mewtwo -> ./mew
 ```
 
 ### `fs.truncate(path[, len], callback)`
@@ -4490,7 +4490,7 @@ changes:
   * `signal` {AbortSignal} allows closing the watcher with an AbortSignal.
 * `listener` {Function|undefined} **Default:** `undefined`
   * `eventType` {string}
-  * `filename` {string|Buffer}
+  * `filename` {string|Buffer|null}
 * Returns: {fs.FSWatcher}
 
 Watch for changes on `filename`, where `filename` is either a file or a

From 42980072e8b5881b4d60373ef6e81e587fedfe83 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Osoba=20S=C5=82awomir?= <slawomir.osoba@coig.pl>
Date: Mon, 24 Apr 2023 09:53:16 +0200
Subject: [PATCH 03/16] Resore unicode glyphs

---
 doc/api/fs.md | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/doc/api/fs.md b/doc/api/fs.md
index c82c18ca603f54..c8b5b02664381a 100644
--- a/doc/api/fs.md
+++ b/doc/api/fs.md
@@ -4282,8 +4282,8 @@ same directory:
 ```bash
 $ tree .
 .
-+¦¦ mew
-L¦¦ mewtwo -> ./mew
+├── mew
+└── mewtwo -> ./mew
 ```
 
 ### `fs.truncate(path[, len], callback)`

From 6ec3d05be1b28d277f4c425bcfa50f7d9c4dd26c Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Osoba=20S=C5=82awomir?= <slawomir.osoba@coig.pl>
Date: Mon, 24 Apr 2023 09:53:37 +0200
Subject: [PATCH 04/16] MoLow suggestion

---
 lib/internal/watch_mode/files_watcher.js | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/internal/watch_mode/files_watcher.js b/lib/internal/watch_mode/files_watcher.js
index 1a622f856aee64..90d2ffd33a9c7b 100644
--- a/lib/internal/watch_mode/files_watcher.js
+++ b/lib/internal/watch_mode/files_watcher.js
@@ -91,7 +91,7 @@ class FilesWatcher extends EventEmitter {
     }
     const watcher = watch(path, { recursive });
     watcher.on('change', (eventType, fileName) => {
-      if (fileName !== null) {
+      if (fileName != null) {
         this.#onChange(recursive ? resolve(path, fileName) : path);
       }
    });

From 6b40a22fdf2053ced2fe38becb22ea95fc1d7299 Mon Sep 17 00:00:00 2001
From: sosoba <slawomir.osoba@coig.pl>
Date: Mon, 24 Apr 2023 07:36:14 +0200
Subject: [PATCH 05/16] Null-proofing

---
 lib/internal/watch_mode/files_watcher.js | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/lib/internal/watch_mode/files_watcher.js b/lib/internal/watch_mode/files_watcher.js
index 3c756c4b5d77c9..1a622f856aee64 100644
--- a/lib/internal/watch_mode/files_watcher.js
+++ b/lib/internal/watch_mode/files_watcher.js
@@ -90,8 +90,11 @@ class FilesWatcher extends EventEmitter {
       return;
     }
     const watcher = watch(path, { recursive });
-    watcher.on('change', (eventType, fileName) => this
-      .#onChange(recursive ? resolve(path, fileName) : path));
+    watcher.on('change', (eventType, fileName) => {
+      if (fileName !== null) {
+        this.#onChange(recursive ? resolve(path, fileName) : path);
+      }
+   });
     this.#watchers.set(path, { handle: watcher, recursive });
     if (recursive) {
       this.#removeWatchedChildren(path);

From 3e91cf2538fa47a5d8150d51bc7fb9625d5c27b6 Mon Sep 17 00:00:00 2001
From: sosoba <slawomir.osoba@coig.pl>
Date: Mon, 24 Apr 2023 09:04:49 +0200
Subject: [PATCH 06/16] Update fs.md

Wath can pass null as filename
---
 doc/api/fs.md | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/doc/api/fs.md b/doc/api/fs.md
index a4efd37018c413..68e4b7fa5d44b2 100644
--- a/doc/api/fs.md
+++ b/doc/api/fs.md
@@ -1667,7 +1667,7 @@ added:
     should stop.
 * Returns: {AsyncIterator} of objects with the properties:
   * `eventType` {string} The type of change
-  * `filename` {string|Buffer} The name of the file changed.
+  * `filename` {string|Buffer|null} The name of the file changed.
 
 Returns an async iterator that watches for changes on `filename`, where `filename`
 is either a file or a directory.
@@ -4281,8 +4281,8 @@ same directory:
 ```bash
 $ tree .
 .
-├── mew
-└── mewtwo -> ./mew
++¦¦ mew
+L¦¦ mewtwo -> ./mew
 ```
 
 ### `fs.truncate(path[, len], callback)`
@@ -4489,7 +4489,7 @@ changes:
   * `signal` {AbortSignal} allows closing the watcher with an AbortSignal.
 * `listener` {Function|undefined} **Default:** `undefined`
   * `eventType` {string}
-  * `filename` {string|Buffer}
+  * `filename` {string|Buffer|null}
 * Returns: {fs.FSWatcher}
 
 Watch for changes on `filename`, where `filename` is either a file or a

From 006abee7e7c95d32968c01d3b03d97a0eb9d4da9 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Osoba=20S=C5=82awomir?= <slawomir.osoba@coig.pl>
Date: Mon, 24 Apr 2023 09:53:16 +0200
Subject: [PATCH 07/16] Resore unicode glyphs

---
 doc/api/fs.md | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/doc/api/fs.md b/doc/api/fs.md
index 68e4b7fa5d44b2..7dd926f18eecaa 100644
--- a/doc/api/fs.md
+++ b/doc/api/fs.md
@@ -4281,8 +4281,8 @@ same directory:
 ```bash
 $ tree .
 .
-+¦¦ mew
-L¦¦ mewtwo -> ./mew
+├── mew
+└── mewtwo -> ./mew
 ```
 
 ### `fs.truncate(path[, len], callback)`

From 267daf5ffb4a2d617501c29fce976d6860c063aa Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Osoba=20S=C5=82awomir?= <slawomir.osoba@coig.pl>
Date: Mon, 24 Apr 2023 09:53:37 +0200
Subject: [PATCH 08/16] MoLow suggestion

---
 lib/internal/watch_mode/files_watcher.js | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/internal/watch_mode/files_watcher.js b/lib/internal/watch_mode/files_watcher.js
index 1a622f856aee64..90d2ffd33a9c7b 100644
--- a/lib/internal/watch_mode/files_watcher.js
+++ b/lib/internal/watch_mode/files_watcher.js
@@ -91,7 +91,7 @@ class FilesWatcher extends EventEmitter {
     }
     const watcher = watch(path, { recursive });
     watcher.on('change', (eventType, fileName) => {
-      if (fileName !== null) {
+      if (fileName != null) {
         this.#onChange(recursive ? resolve(path, fileName) : path);
       }
    });

From 13a6c679fbe3b59673c51f2ab98f35c3ed8e672f Mon Sep 17 00:00:00 2001
From: sosoba <slawomir.osoba@coig.pl>
Date: Mon, 24 Apr 2023 09:04:49 +0200
Subject: [PATCH 09/16] Update fs.md

Wath can pass null as filename
---
 doc/api/fs.md | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/doc/api/fs.md b/doc/api/fs.md
index 7dd926f18eecaa..68e4b7fa5d44b2 100644
--- a/doc/api/fs.md
+++ b/doc/api/fs.md
@@ -4281,8 +4281,8 @@ same directory:
 ```bash
 $ tree .
 .
-├── mew
-└── mewtwo -> ./mew
++¦¦ mew
+L¦¦ mewtwo -> ./mew
 ```
 
 ### `fs.truncate(path[, len], callback)`

From 0c5e9b20a83f9933118ac269e2bb8d8f97b6a6df Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Osoba=20S=C5=82awomir?= <slawomir.osoba@coig.pl>
Date: Mon, 24 Apr 2023 09:53:16 +0200
Subject: [PATCH 10/16] Resore unicode glyphs

---
 doc/api/fs.md | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/doc/api/fs.md b/doc/api/fs.md
index 68e4b7fa5d44b2..7dd926f18eecaa 100644
--- a/doc/api/fs.md
+++ b/doc/api/fs.md
@@ -4281,8 +4281,8 @@ same directory:
 ```bash
 $ tree .
 .
-+¦¦ mew
-L¦¦ mewtwo -> ./mew
+├── mew
+└── mewtwo -> ./mew
 ```
 
 ### `fs.truncate(path[, len], callback)`

From 4ef5a100556aa262e1cbdd83d96c5b00152c1e2e Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Osoba=20S=C5=82awomir?= <slawomir.osoba@coig.pl>
Date: Mon, 24 Apr 2023 12:08:40 +0200
Subject: [PATCH 11/16] fix indent

---
 lib/internal/watch_mode/files_watcher.js | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/internal/watch_mode/files_watcher.js b/lib/internal/watch_mode/files_watcher.js
index 90d2ffd33a9c7b..51d6ebe6154b64 100644
--- a/lib/internal/watch_mode/files_watcher.js
+++ b/lib/internal/watch_mode/files_watcher.js
@@ -94,7 +94,7 @@ class FilesWatcher extends EventEmitter {
       if (fileName != null) {
         this.#onChange(recursive ? resolve(path, fileName) : path);
       }
-   });
+    });
     this.#watchers.set(path, { handle: watcher, recursive });
     if (recursive) {
       this.#removeWatchedChildren(path);

From eb4ddbb36419de6bd4fad3f3a0723b815cfaa6d9 Mon Sep 17 00:00:00 2001
From: sosoba <slawomir.osoba@coig.pl>
Date: Mon, 24 Apr 2023 07:36:14 +0200
Subject: [PATCH 12/16] Null-proofing

---
 lib/internal/watch_mode/files_watcher.js | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/internal/watch_mode/files_watcher.js b/lib/internal/watch_mode/files_watcher.js
index 90d2ffd33a9c7b..51d6ebe6154b64 100644
--- a/lib/internal/watch_mode/files_watcher.js
+++ b/lib/internal/watch_mode/files_watcher.js
@@ -94,7 +94,7 @@ class FilesWatcher extends EventEmitter {
       if (fileName != null) {
         this.#onChange(recursive ? resolve(path, fileName) : path);
       }
-   });
+    });
     this.#watchers.set(path, { handle: watcher, recursive });
     if (recursive) {
       this.#removeWatchedChildren(path);

From a065a3b0dc20cb27b878c1c7f8ab33430658d47f Mon Sep 17 00:00:00 2001
From: sosoba <slawomir.osoba@coig.pl>
Date: Mon, 24 Apr 2023 09:04:49 +0200
Subject: [PATCH 13/16] Update fs.md

Wath can pass null as filename
---
 doc/api/fs.md | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/doc/api/fs.md b/doc/api/fs.md
index 7dd926f18eecaa..68e4b7fa5d44b2 100644
--- a/doc/api/fs.md
+++ b/doc/api/fs.md
@@ -4281,8 +4281,8 @@ same directory:
 ```bash
 $ tree .
 .
-├── mew
-└── mewtwo -> ./mew
++¦¦ mew
+L¦¦ mewtwo -> ./mew
 ```
 
 ### `fs.truncate(path[, len], callback)`

From 8a5862f6fb49a3c68cefa3705708195e8406d7b7 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Osoba=20S=C5=82awomir?= <slawomir.osoba@coig.pl>
Date: Mon, 24 Apr 2023 09:53:16 +0200
Subject: [PATCH 14/16] Resore unicode glyphs

---
 doc/api/fs.md | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/doc/api/fs.md b/doc/api/fs.md
index 68e4b7fa5d44b2..7dd926f18eecaa 100644
--- a/doc/api/fs.md
+++ b/doc/api/fs.md
@@ -4281,8 +4281,8 @@ same directory:
 ```bash
 $ tree .
 .
-+¦¦ mew
-L¦¦ mewtwo -> ./mew
+├── mew
+└── mewtwo -> ./mew
 ```
 
 ### `fs.truncate(path[, len], callback)`

From 5c013dbc2395198f4c46b0fba29cedf1bdf0f1ea Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Osoba=20S=C5=82awomir?= <slawomir.osoba@coig.pl>
Date: Mon, 24 Apr 2023 14:10:44 +0200
Subject: [PATCH 15/16] Add test

---
 lib/internal/watch_mode/files_watcher.js        | 4 ++++
 test/parallel/test-watch-mode-files_watcher.mjs | 8 ++++++++
 2 files changed, 12 insertions(+)

diff --git a/lib/internal/watch_mode/files_watcher.js b/lib/internal/watch_mode/files_watcher.js
index 51d6ebe6154b64..c465668c9821b4 100644
--- a/lib/internal/watch_mode/files_watcher.js
+++ b/lib/internal/watch_mode/files_watcher.js
@@ -85,6 +85,10 @@ class FilesWatcher extends EventEmitter {
     return [...this.#watchers.keys()];
   }
 
+  [Symbol.for('emitChangeEventWithoutFilename')]() {
+    this.#watchers.values().forEach(watcher => watcher.emit('change', 'change', null));
+  }
+
   watchPath(path, recursive = true) {
     if (this.#isPathWatched(path)) {
       return;
diff --git a/test/parallel/test-watch-mode-files_watcher.mjs b/test/parallel/test-watch-mode-files_watcher.mjs
index 19f71a04e40df8..94a88f87a3eeda 100644
--- a/test/parallel/test-watch-mode-files_watcher.mjs
+++ b/test/parallel/test-watch-mode-files_watcher.mjs
@@ -159,4 +159,12 @@ describe('watch mode file watcher', () => {
     }
     assert.deepStrictEqual(watcher.watchedPaths, expected);
   });
+
+  it('should ignore watch event without filename', async () => {
+    watcher.on('changed', common.mustNotCall());
+    watcher.watchPath(tmpdir.path);
+    watcher[Symbol.for('emitChangeEventWithoutFilename')]();
+    // Wait for this long to make sure changes are not triggered
+    await setTimeout(1000);
+  });  
 });

From ad8329479a465c7c7254a6e3509ac20d3135996f Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Osoba=20S=C5=82awomir?= <slawomir.osoba@coig.pl>
Date: Tue, 25 Apr 2023 07:35:55 +0200
Subject: [PATCH 16/16]  Remove a specific method used only by tests

---
 lib/internal/watch_mode/files_watcher.js      | 10 ++++-----
 .../test-watch-mode-files_watcher.mjs         | 22 ++++++++++++++-----
 2 files changed, 20 insertions(+), 12 deletions(-)

diff --git a/lib/internal/watch_mode/files_watcher.js b/lib/internal/watch_mode/files_watcher.js
index c465668c9821b4..015b50d54a948c 100644
--- a/lib/internal/watch_mode/files_watcher.js
+++ b/lib/internal/watch_mode/files_watcher.js
@@ -30,14 +30,16 @@ class FilesWatcher extends EventEmitter {
   #ownerDependencies = new SafeMap();
   #throttle;
   #mode;
+  #createWatcher;
 
-  constructor({ throttle = 500, mode = 'filter' } = kEmptyObject) {
+  constructor({ throttle = 500, mode = 'filter', createWatcher = watch } = kEmptyObject) {
     super();
 
     validateNumber(throttle, 'options.throttle', 0, TIMEOUT_MAX);
     validateOneOf(mode, 'options.mode', ['filter', 'all']);
     this.#throttle = throttle;
     this.#mode = mode;
+    this.#createWatcher = createWatcher;
   }
 
   #isPathWatched(path) {
@@ -85,15 +87,11 @@ class FilesWatcher extends EventEmitter {
     return [...this.#watchers.keys()];
   }
 
-  [Symbol.for('emitChangeEventWithoutFilename')]() {
-    this.#watchers.values().forEach(watcher => watcher.emit('change', 'change', null));
-  }
-
   watchPath(path, recursive = true) {
     if (this.#isPathWatched(path)) {
       return;
     }
-    const watcher = watch(path, { recursive });
+    const watcher = this.#createWatcher(path, { recursive });
     watcher.on('change', (eventType, fileName) => {
       if (fileName != null) {
         this.#onChange(recursive ? resolve(path, fileName) : path);
diff --git a/test/parallel/test-watch-mode-files_watcher.mjs b/test/parallel/test-watch-mode-files_watcher.mjs
index 94a88f87a3eeda..47a142d38f84c0 100644
--- a/test/parallel/test-watch-mode-files_watcher.mjs
+++ b/test/parallel/test-watch-mode-files_watcher.mjs
@@ -6,7 +6,7 @@ import path from 'node:path';
 import assert from 'node:assert';
 import process from 'node:process';
 import { describe, it, beforeEach, afterEach } from 'node:test';
-import { writeFileSync, mkdirSync } from 'node:fs';
+import { writeFileSync, mkdirSync, watch } from 'node:fs';
 import { setTimeout } from 'node:timers/promises';
 import { once } from 'node:events';
 import { spawn } from 'node:child_process';
@@ -161,10 +161,20 @@ describe('watch mode file watcher', () => {
   });
 
   it('should ignore watch event without filename', async () => {
-    watcher.on('changed', common.mustNotCall());
-    watcher.watchPath(tmpdir.path);
-    watcher[Symbol.for('emitChangeEventWithoutFilename')]();
-    // Wait for this long to make sure changes are not triggered
-    await setTimeout(1000);
+    let watcher;
+    const createWatcher = (filename, options, listener) => {
+      watcher = watch(filename, options, listener);
+      return watcher;
+    };
+    const filesWatcher = new FilesWatcher({ throttle: 100, createWatcher });
+    try {
+      filesWatcher.on('changed', common.mustNotCall());
+      filesWatcher.watchPath(tmpdir.path);
+      watcher.emit('change', 'change', null);
+      // Wait for this long to make sure changes are not triggered
+      await setTimeout(1000);
+    } finally {
+      filesWatcher.clear();
+    }
   });  
 });