Race condition on FunctionReturns while simultaneously calling Function

[NilsJPWerner]

I run into a race condition when I have a go routine constantly calling a function while simultaneously changing the return value of the function with functionReturns.

I have pinpointed the issue to the faked function unlocking its mutex too early. The faked function should only unlock the function mutex after checking whether the function stub is nil. In the current version both the main function and the functionReturns can access the stub at the same time causing test failures.

func (fake *FakeService) RaceClosed(arg1 string, arg2 string, arg3 int) (bool, error) {
	fake.raceClosedMutex.Lock()
	ret, specificReturn := fake.raceClosedReturnsOnCall[len(fake.raceClosedArgsForCall)]
	fake.raceClosedArgsForCall = append(fake.raceClosedArgsForCall, struct {
		arg1 string
		arg2 string
		arg3 int
	}{arg1, arg2, arg3})
	fake.recordInvocation("RaceClosed", []interface{}{arg1, arg2, arg3})  
	fake.raceClosedMutex.Unlock()         // This needs to be moved to later in the function
	if fake.RaceClosedStub != nil {       // This line is where data races happen
		return fake.RaceClosedStub(arg1, arg2, arg3)
	}
	if specificReturn {
		return ret.result1, ret.result2
	}
	fakeReturns := fake.raceClosedReturns
	return fakeReturns.result1, fakeReturns.result2
}

func (fake *FakeService) RaceClosedReturns(result1 bool, result2 error) {
	fake.raceClosedMutex.Lock()
	defer fake.raceClosedMutex.Unlock()
	fake.RaceClosedStub = nil        // This line is the other side of the data race
	fake.raceClosedReturns = struct {
		result1 bool
		result2 error
	}{result1, result2}
}

I can create a PR to move this line later: https://github.com/maxbrunsfeld/counterfeiter/blob/master/generator/interface_template.go#L70 of to make it deferred.

[NilsJPWerner]

If I create a PR will someone merge it in?

[NilsJPWerner]

Bump