bootstrap: run preload prior to --frozen-intrinsics

doc/api/cli.md

@@ -218,6 +218,9 @@ Support is currently only provided for the root context and no guarantees are
 currently provided that `global.Array` is indeed the default intrinsic
 reference. Code may break under this flag.
 
+`--require` runs prior to freezing intrinsics in order to allow polyfills to
+be added.
+
 ### `--heapsnapshot-signal=signal`
 <!-- YAML
 added: v12.0.0

lib/internal/bootstrap/pre_execution.js

@@ -48,10 +48,10 @@ function prepareMainThreadExecution(expandArgv1 = false) {
   initializeClusterIPC();
 
   initializeDeprecations();
-  initializeFrozenIntrinsics();
   initializeCJSLoader();
   initializeESMLoader();
   loadPreloadModules();
+  initializeFrozenIntrinsics();
 }
 
 function patchProcessObject(expandArgv1) {

lib/internal/main/worker_thread.js

@@ -106,10 +106,10 @@ port.on('message', (message) => {
       require('internal/process/policy').setup(manifestSrc, manifestURL);
     }
     initializeDeprecations();
-    initializeFrozenIntrinsics();
     initializeCJSLoader();
     initializeESMLoader();
     loadPreloadModules();
+    initializeFrozenIntrinsics();
     publicWorker.parentPort = publicPort;
     publicWorker.workerData = workerData;
 

test/fixtures/intrinsic-mutation.js

@@ -0,0 +1,10 @@
+'use strict';
+Object.defineProperty(
+  Object.prototype,
+  'flatten', {
+    enumerable: false,
+    // purposefully named something that
+    // would never land in JS itself
+    value: function smoosh() {}
+  }
+);

test/fixtures/print-intrinsic-mutation-name.js

@@ -0,0 +1,2 @@
+'use strict';
+console.log({}.flatten.name);

test/fixtures/worker-from-argv.js

@@ -0,0 +1,3 @@
+'use strict';
+const {Worker} = require('worker_threads');
+new Worker(process.argv[2]).on('exit', process.exit);

test/parallel/test-preload.js

@@ -23,6 +23,9 @@ const fixtureA = fixtures.path('printA.js');
 const fixtureB = fixtures.path('printB.js');
 const fixtureC = fixtures.path('printC.js');
 const fixtureD = fixtures.path('define-global.js');
+const fixtureE = fixtures.path('intrinsic-mutation.js');
+const fixtureF = fixtures.path('print-intrinsic-mutation-name.js');
+const fixtureG = fixtures.path('worker-from-argv.js');
 const fixtureThrows = fixtures.path('throws_error4.js');
 
 // Test preloading a single module works
@@ -62,6 +65,32 @@ childProcess.exec(
   }
 );
 
+// Test that preload can be used with --frozen-intrinsics
+childProcess.exec(
+  `"${nodeBinary}" --frozen-intrinsics ${
+    preloadOption([fixtureE])
+  } ${
+    fixtureF
+  }`,
+  function(err, stdout) {
+    assert.ifError(err);
+    assert.strictEqual(stdout, 'smoosh\n');
+  }
+);
+childProcess.exec(
+  `"${
+    nodeBinary
+  }" --frozen-intrinsics ${
+    preloadOption([fixtureE])
+  } ${
+    fixtureG
+  } ${fixtureF}`,
+  function(err, stdout) {
+    assert.ifError(err);
+    assert.strictEqual(stdout, 'smoosh\n');
+  }
+);
+
 // Test that preload can be used with stdin
 const stdinProc = childProcess.spawn(
   nodeBinary,