process: fix call process.reallyExit, vs., binding

Some user-land modules, e.g., nyc, mocha, currently rely on patching
process.reallyExit.
PR-URL: #25655Fixes: #25650
Reviewed-By: Gus Caplan <me@gus.host>
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Joyee Cheung <joyeec9h3@gmail.com>
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>

Author: bcoe

lib/internal/process/per_thread.js

@@ -149,7 +149,10 @@ function wrapProcessMethods(binding) {
 process._exiting=true;
 process.emit('exit',process.exitCode||0);
 }
-binding.reallyExit(process.exitCode||0);
+// FIXME(joyeecheung): This is an undocumented API that gets monkey-patched
+// in the user land. Either document it, or deprecate it in favor of a
+// better public alternative.
+process.reallyExit(process.exitCode||0);
 }
 
 functionkill(pid,sig){

test/parallel/test-process-really-exit.js

@@ -0,0 +1,17 @@
+'use strict';
+require('../common');
+constassert=require('assert');
+
+// ensure that the reallyExit hook is executed.
+// see: https://github.com/nodejs/node/issues/25650
+if(process.argv[2]==='subprocess'){
+process.reallyExit=function(){
+console.info('really exited');
+};
+process.exit();
+}else{
+const{ spawnSync }=require('child_process');
+constout=spawnSync(process.execPath,[__filename,'subprocess']);
+constobserved=out.output[1].toString('utf8').trim();
+assert.strictEqual(observed,'really exited');
+}