feat: Explicit Resource Management support in mocked functions (#7927)

Author: EskiMojo14

docs/api/vi.md

@@ -459,6 +459,19 @@ expect(spy).toHaveBeenCalled()
 expect(spy).toHaveReturnedWith(1)
 ```
 
+::: tip
+In environments that support [Explicit Resource Management](https://github.com/tc39/proposal-explicit-resource-management), you can use `using` instead of `const` to automatically call `mockRestore` on any mocked function when the containing block is exited. This is especially useful for spied methods:
+
+```ts
+it('calls console.log', () => {
+  using spy = vi.spyOn(console, 'log').mockImplementation(() => {})
+  debug('message')
+  expect(spy).toHaveBeenCalled()
+})
+// console.log is restored here
+```
+:::
+
 ::: tip
 You can call [`vi.restoreAllMocks`](#vi-restoreallmocks) inside [`afterEach`](/api/#aftereach) (or enable [`test.restoreMocks`](/config/#restoreMocks)) to restore all methods to their original implementations. This will restore the original [object descriptor](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/defineProperty), so you won't be able to change method's implementation:
 

packages/spy/src/index.ts

@@ -175,7 +175,7 @@ Jest uses the latter for `MockInstance.mockImplementation` etc... and it allows
   const boolFn: Jest.Mock<() => boolean> = jest.fn<() => true>(() => true)
 */
 /* eslint-disable ts/method-signature-style */
-export interface MockInstance<T extends Procedure = Procedure> {
+export interface MockInstance<T extends Procedure = Procedure> extends Disposable {
   /**
    * Use it to return the name assigned to the mock with the `.mockName(name)` method. By default, it will return `vi.fn()`.
    * @see https://vitest.dev/api/mock#getmockname
@@ -549,6 +549,10 @@ function enhanceSpy<T extends Procedure>(
     return stub
   }
 
+  if (Symbol.dispose) {
+    stub[Symbol.dispose] = () => stub.mockRestore()
+  }
+
   stub.getMockImplementation = () =>
     implementationChangedTemporarily ? implementation : (onceImplementations.at(0) || implementation)
   stub.mockImplementation = (fn: T) => {

test/core/test/jest-mock.test.ts

@@ -560,6 +560,30 @@ describe('jest mock compat layer', () => {
     expect(fn.getMockImplementation()).toBe(temporaryMockImplementation)
   })
 
+  describe('is disposable', () => {
+    describe.runIf(Symbol.dispose)('in environments supporting it', () => {
+      it('has dispose property', () => {
+        expect(vi.fn()[Symbol.dispose]).toBeTypeOf('function')
+      })
+      it('calls mockRestore when disposing', () => {
+        const fn = vi.fn()
+        const restoreSpy = vi.spyOn(fn, 'mockRestore')
+        {
+          using _fn2 = fn
+        }
+        expect(restoreSpy).toHaveBeenCalled()
+      })
+      it('allows disposal when using mockImplementation', () => {
+        expect(vi.fn().mockImplementation(() => {})[Symbol.dispose]).toBeTypeOf('function')
+      })
+    })
+    describe.skipIf(Symbol.dispose)('in environments not supporting it', () => {
+      it('does not have dispose property', () => {
+        expect(vi.fn()[Symbol.dispose]).toBeUndefined()
+      })
+    })
+  })
+
   describe('docs example', () => {
     it('mockClear', () => {
       const person = {