fs: do not crash if the watched file is removed while setting up watch

Signed-off-by: Matteo Collina <hello@matteocollina.com>
PR-URL: #53452
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Moshe Atlow <moshe@atlow.co.il>
Reviewed-By: Marco Ippolito <marcoippolito54@gmail.com>
Reviewed-By: Chemi Atlow <chemi@atlow.co.il>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Yagiz Nizipli <yagiz.nizipli@sentry.io>

Author: mcollina

lib/internal/fs/recursive_watch.js

@@ -83,7 +83,7 @@ class FSWatcher extends EventEmitter {
 this.#closed =true;
 
 for(constfileofthis.#files.keys()){
-this.#watchers.get(file).close();
+this.#watchers.get(file)?.close();
 this.#watchers.delete(file);
 }
 
@@ -98,7 +98,7 @@ class FSWatcher extends EventEmitter {
 for(constfilenameofthis.#files.keys()){
 if(StringPrototypeStartsWith(filename,file)){
 this.#files.delete(filename);
-this.#watchers.get(filename).close();
+this.#watchers.get(filename)?.close();
 this.#watchers.delete(filename);
 }
 }
@@ -126,9 +126,16 @@ class FSWatcher extends EventEmitter {
 this.#symbolicFiles.add(f);
 }
 
-this.#watchFile(f);
-if(file.isDirectory()&&!file.isSymbolicLink()){
-this.#watchFolder(f);
+try{
+this.#watchFile(f);
+if(file.isDirectory()&&!file.isSymbolicLink()){
+this.#watchFolder(f);
+}
+}catch(err){
+// Ignore ENOENT
+if(err.code!=='ENOENT'){
+throwerr;
+}
 }
 }
 }

test/parallel/test-fs-watch-recursive-linux-parallel-remove.js

@@ -0,0 +1,33 @@
+'use strict';
+
+constcommon=require('../common');
+
+if(!common.isLinux)
+common.skip('This test can run only on Linux');
+
+// Test that the watcher do not crash if the file "disappears" while
+// watch is being set up.
+
+constpath=require('node:path');
+constfs=require('node:fs');
+const{ spawn }=require('node:child_process');
+
+consttmpdir=require('../common/tmpdir');
+consttestDir=tmpdir.path;
+tmpdir.refresh();
+
+constwatcher=fs.watch(testDir,{recursive: true});
+watcher.on('change',function(event,filename){
+// This console.log makes the error happen
+// do not remove
+console.log(filename,event);
+});
+
+consttestFile=path.join(testDir,'a');
+constchild=spawn(process.argv[0],['-e',`const fs = require('node:fs'); for (let i = 0; i < 10000; i++) { const fd = fs.openSync('${testFile}', 'w'); fs.writeSync(fd, Buffer.from('hello')); fs.rmSync('${testFile}') }`],{
+stdio: 'inherit'
+});
+
+child.on('exit',function(){
+watcher.close();
+});