fix: babel-register transform internal dependencies (#12665)

Closes #11964, #12662.

packages/babel-register/src/index.js

@@ -9,7 +9,7 @@ exports = module.exports = function (...args) {
 };
 exports.__esModule = true;
 
-const node = require("./node");
+const node = require("./nodeWrapper");
 const register = node.default;
 
 Object.assign(exports, node);

packages/babel-register/src/node.js

@@ -7,6 +7,7 @@ import { OptionManager, DEFAULT_EXTENSIONS } from "@babel/core";
 import { addHook } from "pirates";
 import fs from "fs";
 import path from "path";
+import Module from "module";
 
 const maps = {};
 let transformOpts = {};
@@ -82,15 +83,19 @@ function compile(code, filename) {
 }
 
 let compiling = false;
+const internalModuleCache = Module._cache;
 
 function compileHook(code, filename) {
   if (compiling) return code;
 
+  const globalModuleCache = Module._cache;
   try {
     compiling = true;
+    Module._cache = internalModuleCache;
     return compile(code, filename);
   } finally {
     compiling = false;
+    Module._cache = globalModuleCache;
   }
 }
 

packages/babel-register/src/nodeWrapper.js

@@ -0,0 +1,21 @@
+/**
+ * This file wraps the implementation of register so all modules `require()`-ed
+ * internally within register are stored in a separate module cache.
+ * This prevents un-transformed modules being stored in global module cache,
+ * and allows register to transform these modules if they are loaded externally.
+ */
+
+const Module = require("module");
+
+const globalModuleCache = Module._cache;
+const internalModuleCache = Object.create(null);
+
+Module._cache = internalModuleCache;
+const node = require("./node");
+Module._cache = globalModuleCache;
+
+// Add source-map-support to global cache as it's stateful
+const smsPath = require.resolve("source-map-support");
+globalModuleCache[smsPath] = internalModuleCache[smsPath];
+
+module.exports = node;