process: fix finalization cleanup ref tracking

lib/internal/process/finalization.js

@@ -2,11 +2,8 @@
 // This file is a modified version of the on-exit-leak-free module on npm.
 
 const {
-  ArrayPrototypeFilter,
-  ArrayPrototypeIndexOf,
-  ArrayPrototypePush,
-  ArrayPrototypeSplice,
   SafeFinalizationRegistry,
+  SafeSet,
   SafeWeakRef,
 } = primordials;
 const { validateObject, kValidateObjectAllowFunction } = require('internal/validators');
@@ -20,8 +17,8 @@ function createFinalization() {
 
   const refs = {
     __proto__: null,
-    exit: [],
-    beforeExit: [],
+    exit: new SafeSet(),
+    beforeExit: new SafeSet(),
   };
 
   const functions = {
@@ -31,21 +28,21 @@ function createFinalization() {
   };
 
   function install(event) {
-    if (refs[event].length > 0) {
+    if (refs[event].size > 0) {
       return;
     }
 
     process.on(event, functions[event]);
   }
 
   function uninstall(event) {
-    if (refs[event].length > 0) {
+    if (refs[event].size > 0) {
       return;
     }
 
     process.removeListener(event, functions[event]);
 
-    if (refs.exit.length === 0 && refs.beforeExit.length === 0) {
+    if (refs.exit.size === 0 && refs.beforeExit.size === 0) {
       registry = null;
     }
   }
@@ -70,14 +67,14 @@ function createFinalization() {
         fn(obj, event);
       }
     }
-    refs[event] = [];
+    refs[event].clear();
   }
 
   function clear(ref) {
     for (const event of ['exit', 'beforeExit']) {
-      const index = ArrayPrototypeIndexOf(refs[event], ref);
-      ArrayPrototypeSplice(refs[event], index, index + 1);
-      uninstall(event);
+      if (refs[event].delete(ref)) {
+        uninstall(event);
+      }
     }
   }
 
@@ -90,7 +87,7 @@ function createFinalization() {
     registry ||= new SafeFinalizationRegistry(clear);
     registry.register(obj, ref);
 
-    ArrayPrototypePush(refs[event], ref);
+    refs[event].add(ref);
   }
 
   /**
@@ -130,10 +127,12 @@ function createFinalization() {
     }
     registry.unregister(obj);
     for (const event of ['exit', 'beforeExit']) {
-      refs[event] = ArrayPrototypeFilter(refs[event], (ref) => {
+      for (const ref of refs[event]) {
         const _obj = ref.deref();
-        return _obj && _obj !== obj;
-      });
+        if (!_obj || _obj === obj) {
+          refs[event].delete(ref);
+        }
+      }
       uninstall(event);
     }
   }

test/fixtures/process/finalization-cleanup.mjs

@@ -0,0 +1,34 @@
+import { deepStrictEqual } from 'assert'
+import { setImmediate } from 'timers/promises'
+
+const keptAlive = []
+const finalized = []
+
+function onFinalize(obj) {
+  finalized.push(obj.name)
+}
+
+{
+  const first = { name: 'first' }
+  let collected = { name: 'collected' }
+  const third = { name: 'third' }
+
+  keptAlive.push(first, third)
+
+  process.finalization.register(first, onFinalize)
+  process.finalization.register(collected, onFinalize)
+  process.finalization.register(third, onFinalize)
+
+  collected = null
+}
+
+// Give V8 a few chances to collect `collected` and run the
+// FinalizationRegistry cleanup before process exit.
+for (let i = 0; i < 10; i++) {
+  gc()
+  await setImmediate()
+}
+
+process.on('exit', function () {
+  deepStrictEqual(finalized, ['first', 'third'])
+})

test/parallel/test-process-finalization.mjs

@@ -9,6 +9,7 @@ import assert from 'assert';
 const files = [
   'close.mjs',
   'before-exit.mjs',
+  'finalization-cleanup.mjs',
   'gc-not-close.mjs',
   'unregister.mjs',
   'different-registry-per-thread.mjs',