fix(jest-runtime): prevent global module registry from leaking into isolateModules registry

CHANGELOG.md

@@ -37,6 +37,7 @@
 - `[jest-runtime]` [**BREAKING**] Do not inject `global` variable into module wrapper ([#10644](https://github.com/facebook/jest/pull/10644))
 - `[jest-runtime]` [**BREAKING**] remove long-deprecated `jest.addMatchers`, `jest.resetModuleRegistry`, and `jest.runTimersToTime` ([#9853](https://github.com/facebook/jest/pull/9853))
 - `[jest-runtime]` Fix stack overflow and promise deadlock when importing mutual dependant ES module ([#10892](https://github.com/facebook/jest/pull/10892))
+- `[jest-runtime]` Prevent global module registry from leaking into `isolateModules` registry ([#10963](https://github.com/facebook/jest/pull/10963))
 - `[jest-transform]` Show enhanced `SyntaxError` message for all `SyntaxError`s ([#10749](https://github.com/facebook/jest/pull/10749))
 - `[jest-transform]` [**BREAKING**] Refactor API to pass an options bag around rather than multiple boolean options ([#10753](https://github.com/facebook/jest/pull/10753))
 - `[jest-transform]` [**BREAKING**] Refactor API of transformers to pass an options bag rather than separate `config` and other options ([#10834](https://github.com/facebook/jest/pull/10834))

packages/jest-runtime/src/__tests__/runtime_require_module_or_mock.test.js

@@ -218,6 +218,33 @@ describe('resetModules', () => {
 });
 
 describe('isolateModules', () => {
+  it("keeps it's registry isolated from global one", () =>
+    createRuntime(__filename, {
+      moduleNameMapper,
+    }).then(runtime => {
+      let exports;
+      exports = runtime.requireModuleOrMock(
+        runtime.__mockRootPath,
+        'ModuleWithState',
+      );
+      exports.increment();
+      expect(exports.getState()).toBe(2);
+
+      runtime.isolateModules(() => {
+        exports = runtime.requireModuleOrMock(
+          runtime.__mockRootPath,
+          'ModuleWithState',
+        );
+        expect(exports.getState()).toBe(1);
+      });
+
+      exports = runtime.requireModuleOrMock(
+        runtime.__mockRootPath,
+        'ModuleWithState',
+      );
+      expect(exports.getState()).toBe(2);
+    }));
+
   it('resets all modules after the block', () =>
     createRuntime(__filename, {
       moduleNameMapper,

packages/jest-runtime/src/index.ts

@@ -610,13 +610,10 @@ export default class Runtime {
     if (options?.isInternalModule) {
       moduleRegistry = this._internalModuleRegistry;
     } else {
-      if (
-        this._moduleRegistry.get(modulePath) ||
-        !this._isolatedModuleRegistry
-      ) {
-        moduleRegistry = this._moduleRegistry;
-      } else {
+      if (this._isolatedModuleRegistry) {
         moduleRegistry = this._isolatedModuleRegistry;
+      } else {
+        moduleRegistry = this._moduleRegistry;
       }
     }