fix: Memory leak when deep cloning in babel-core (#14583)

* fix

* review

* review

* fix and rebase

* improve typing

* review

* fix test

packages/babel-core/package.json

@@ -41,11 +41,9 @@
     "./lib/config/files/index.js": "./lib/config/files/index-browser.js",
     "./lib/config/resolve-targets.js": "./lib/config/resolve-targets-browser.js",
     "./lib/transform-file.js": "./lib/transform-file-browser.js",
-    "./lib/transformation/util/clone-deep.js": "./lib/transformation/util/clone-deep-browser.js",
     "./src/config/files/index.ts": "./src/config/files/index-browser.ts",
     "./src/config/resolve-targets.ts": "./src/config/resolve-targets-browser.ts",
-    "./src/transform-file.ts": "./src/transform-file-browser.ts",
-    "./src/transformation/util/clone-deep.ts": "./src/transformation/util/clone-deep-browser.ts"
+    "./src/transform-file.ts": "./src/transform-file-browser.ts"
   },
   "dependencies": {
     "@ampproject/remapping": "^2.1.0",

packages/babel-core/src/transformation/util/clone-deep.ts

@@ -1,9 +1,32 @@
-import v8 from "v8";
-import cloneDeep from "./clone-deep-browser";
-
-export default function (value) {
-  if (v8.deserialize && v8.serialize) {
-    return v8.deserialize(v8.serialize(value));
+//https://github.com/babel/babel/pull/14583#discussion_r882828856
+function deepClone(value: any, cache: Map<any, any>): any {
+  if (value !== null) {
+    if (cache.has(value)) return cache.get(value);
+    let cloned: any;
+    if (Array.isArray(value)) {
+      cloned = new Array(value.length);
+      for (let i = 0; i < value.length; i++) {
+        cloned[i] =
+          typeof value[i] !== "object" ? value[i] : deepClone(value[i], cache);
+      }
+    } else {
+      cloned = {};
+      const keys = Object.keys(value);
+      for (let i = 0; i < keys.length; i++) {
+        const key = keys[i];
+        cloned[key] =
+          typeof value[key] !== "object"
+            ? value[key]
+            : deepClone(value[key], cache);
+      }
+    }
+    cache.set(value, cloned);
+    return cloned;
   }
-  return cloneDeep(value);
+  return value;
+}
+
+export default function <T>(value: T): T {
+  if (typeof value !== "object") return value;
+  return deepClone(value, new Map());
 }

packages/babel-core/test/api.js

@@ -261,7 +261,45 @@ describe("api", function () {
     },
   );
 
-  it("transformFromAstSync should not mutate the AST", function () {
+  it("transformFromAst should generate same code with different cloneInputAst", function () {
+    const program = `//test1
+    /*test2*/var/*test3*/ a = 1/*test4*/;//test5
+    //test6
+    var b;
+    `;
+    const node = parseSync(program);
+    const { code } = transformFromAstSync(node, program, {
+      plugins: [
+        function () {
+          return {
+            visitor: {
+              Identifier: function (path) {
+                path.node.name = "replaced";
+              },
+            },
+          };
+        },
+      ],
+    });
+    const { code: code2 } = transformFromAstSync(node, program, {
+      cloneInputAst: false,
+      plugins: [
+        function () {
+          return {
+            visitor: {
+              Identifier: function (path) {
+                path.node.name = "replaced";
+              },
+            },
+          };
+        },
+      ],
+    });
+
+    expect(code).toBe(code2);
+  });
+
+  it("transformFromAst should not mutate the AST", function () {
     const program = "const identifier = 1";
     const node = parseSync(program);
     const { code } = transformFromAstSync(node, program, {