process: remove process.exit(), process.exitCode coercion to integer

doc/api/deprecations.md

@@ -3178,6 +3178,9 @@ thing instead.
 
 <!-- YAML
 changes:
+  - version: REPLACEME
+    pr-url: https://github.com/nodejs/node/pull/43716
+    description: End-of-Life.
   - version: v19.0.0
     pr-url: https://github.com/nodejs/node/pull/44711
     description: Runtime deprecation.
@@ -3195,7 +3198,7 @@ changes:
                  coercion.
 -->
 
-Type: Runtime
+Type: End-of-Life
 
 Values other than `undefined`, `null`, integer numbers, and integer strings
 (e.g., `'1'`) are deprecated as value for the `code` parameter in

doc/api/process.md

@@ -1708,9 +1708,15 @@ that started the Node.js process. Symbolic links, if any, are resolved.
 
 <!-- YAML
 added: v0.1.13
+changes:
+  - version: REPLACEME
+    pr-url: https://github.com/nodejs/node/pull/43716
+    description: Only accepts a code of type number, or of type string if it
+                 represents an integer.
 -->
 
-* `code` {integer} The exit code. **Default:** `0`.
+* `code` {integer|string|null|undefined} The exit code. For string type, only
+  integer strings (e.g.,'1') are allowed. **Default:** `0`.
 
 The `process.exit()` method instructs Node.js to terminate the process
 synchronously with an exit status of `code`. If `code` is omitted, exit uses
@@ -1810,9 +1816,15 @@ than the current process.
 
 <!-- YAML
 added: v0.11.8
+changes:
+  - version: REPLACEME
+    pr-url: https://github.com/nodejs/node/pull/43716
+    description: Only accepts a code of type number, or of type string if it
+                 represents an integer.
 -->
 
-* {integer}
+* {integer|string|null|undefined} The exit code. For string type, only
+  integer strings (e.g.,'1') are allowed. **Default:** `undefined`.
 
 A number which will be the process exit code, when the process either
 exits gracefully, or is exited via [`process.exit()`][] without specifying

lib/internal/bootstrap/node.js

@@ -60,6 +60,8 @@ const {
   ArrayPrototypeFill,
   FunctionPrototypeCall,
   JSONParse,
+  Number,
+  NumberIsNaN,
   ObjectDefineProperty,
   ObjectGetPrototypeOf,
   ObjectSetPrototypeOf,
@@ -74,6 +76,9 @@ const {
   deprecate,
   exposeInterface,
 } = require('internal/util');
+const {
+  validateInteger,
+} = require('internal/validators');
 const {
   exiting_aliased_Uint32Array,
   getHiddenValue,
@@ -103,12 +108,6 @@ process.domain = null;
 process._exiting = false;
 
 {
-  const warnIntegerCoercionDeprecation = deprecate(
-    () => {},
-    'Implicit coercion to integer for exit code is deprecated.',
-    'DEP0164'
-  );
-
   let exitCode;
 
   ObjectDefineProperty(process, 'exitCode', {
@@ -117,8 +116,13 @@ process._exiting = false;
       return exitCode;
     },
     set(code) {
-      if (perThreadSetup.isDeprecatedExitCode(code)) {
-        warnIntegerCoercionDeprecation();
+      if (code !== null && code !== undefined) {
+        let value = code;
+        if (typeof code === 'string' && code !== '' &&
+          NumberIsNaN((value = Number(code)))) {
+          value = code;
+        }
+        validateInteger(value, 'code');
       }
       exitCode = code;
     },

lib/internal/process/per_thread.js

@@ -13,10 +13,7 @@ const {
   ArrayPrototypeSplice,
   BigUint64Array,
   Float64Array,
-  Number,
-  NumberIsInteger,
   NumberMAX_SAFE_INTEGER,
-  NumberMIN_SAFE_INTEGER,
   ObjectFreeze,
   ObjectDefineProperty,
   ReflectApply,
@@ -183,25 +180,12 @@ function wrapProcessMethods(binding) {
 
   memoryUsage.rss = rss;
 
-  const { deprecate } = require('internal/util');
-  const warnIntegerCoercionDeprecationSync = deprecate(
-    () => {},
-    'Implicit coercion to integer for exit code is deprecated.',
-    'DEP0164',
-    true
-  );
-
   function exit(code) {
     process.off('exit', handleProcessExit);
 
-    if (isDeprecatedExitCode(code)) {
-      // Emit the deprecation warning synchronously since deprecation warning is
-      // generally emitted in a next tick but we have no next tick timing here.
-      warnIntegerCoercionDeprecationSync();
-    }
-
-    if (code || code === 0)
+    if (arguments.length !== 0) {
       process.exitCode = code;
+    }
 
     if (!process._exiting) {
       process._exiting = true;
@@ -424,23 +408,6 @@ function toggleTraceCategoryState(asyncHooksEnabled) {
   }
 }
 
-function isDeprecatedExitCode(code) {
-  if (code !== null && code !== undefined) {
-    const value =
-      typeof code === 'string' && code !== '' ? Number(code) : code;
-    // Check if the value is an integer.
-    if (
-      typeof value !== 'number' ||
-      !NumberIsInteger(value) ||
-      value < NumberMIN_SAFE_INTEGER ||
-      value > NumberMAX_SAFE_INTEGER
-    ) {
-      return true;
-    }
-  }
-  return false;
-}
-
 module.exports = {
   toggleTraceCategoryState,
   assert,
@@ -449,5 +416,4 @@ module.exports = {
   hrtime,
   hrtimeBigInt,
   refreshHrtimeBuffer,
-  isDeprecatedExitCode,
 };