remove "patch has been existed" check

[zhongyuanjia]

Take a look at the following code

type Repo struct {}

func (r *Repo) A() error { return errors.New("A") }

func (r *Repo) B() error { return errors.New("B") }

type Biz struct {
    repo *Repo
}

func (b *Biz) Do() error { 
    if err := b.repo.A(); err != nil { return err }
    return b.repo.B()
}

func Test() {
    patches := gomonkey.NewPatches()
    defer patches.Reset()

    biz := &Biz{repo: &Repo{}}
    // common patch
    patches.ApplyMethodReturn(biz.repo, "A", nil)             

        // test a scene
    patches.ApplyMethodReturn(biz.repo, "B", nil)
    err := biz.Do()
        So(err, ShouldBeNil)

        // test b scene
        // currently it will panic "patch has been existed"
        // what I need is to override the last patch
        patches.ApplyMethodReturn(biz.repo, "B", errors.New("error"))
        err = biz.Do()
        So(err, ShouldNotBeNil)
 }

[agiledragon]

Of course not! I suggest you to use a testing framework like goconvey, testify, and so on. Your test case is not single, it should be split into two. If you don't want to split the test case，you can use another API like ApplyMethodSeq.

[zhongyuanjia]

The following code is valid for version 2.2.0

patches := gomonkey.NewPatches()
defer patches.Reset()   
patches.ApplyMethod(val, "A", func() error { return nil })  
patches.ApplyMethod(val, "A", func() error { return errors.New("test") })   
val.A() // will return test error

When I upgrade to a new version, the above code reports a "patch has been exists" error

So I needed a way to bypass detection, This is the PR