handling circular/shared structures in deep-clone (#15366)

Co-authored-by: liuxingbaoyu <30521560+liuxingbaoyu@users.noreply.github.com>

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

@@ -5,12 +5,14 @@ function deepClone(value: any, cache: Map<any, any>): any {
     let cloned: any;
     if (Array.isArray(value)) {
       cloned = new Array(value.length);
+      cache.set(value, cloned);
       for (let i = 0; i < value.length; i++) {
         cloned[i] =
           typeof value[i] !== "object" ? value[i] : deepClone(value[i], cache);
       }
     } else {
       cloned = {};
+      cache.set(value, cloned);
       const keys = Object.keys(value);
       for (let i = 0; i < keys.length; i++) {
         const key = keys[i];
@@ -20,7 +22,6 @@ function deepClone(value: any, cache: Map<any, any>): any {
             : deepClone(value[key], cache);
       }
     }
-    cache.set(value, cloned);
     return cloned;
   }
   return value;

packages/babel-core/test/api.js

@@ -300,6 +300,16 @@ describe("api", function () {
     expect(code).toBe(code2);
   });
 
+  it("transformFromAstSync should not cause infinite recursion with circular objects", () => {
+    const program = "const identifier = 1";
+    const node = parseSync(program);
+    node.program.body[0].extra = { parent: node.program };
+
+    expect(transformFromAstSync(node, program, {}).code).toBe(
+      "const identifier = 1;",
+    );
+  });
+
   it("transformFromAst should not mutate the AST", function () {
     const program = "const identifier = 1";
     const node = parseSync(program);