promises.mm

// before the change

BAPromise *promise = [self methodThatReturnsAPromise];
[promise then:^id(id obj) {
    NSLog(@"1st");
    return [[self otherMethodThatReturnsAPromise] then:^id(id obj) {
        NSLog(@"2nd");
        return obj;
    }];
}];
[promise done:^(id obj) {
    NSLog(@"3rd");
}];

// after the change

BAPromise *promise = [self methodThatReturnsAPromise];
[promise then:^id(id obj) {
    NSLog(@"1st");
    return obj;
}];
[promise then:^id(id obj) {
    NSLog(@"2nd");
    return [[self otherMethodThatReturnsAPromise] then:^id(id obj) {
        NSLog(@"4th");
        return obj;
    }];
}];
[promise done:^(id obj) {
    NSLog(@"3rd");
}];

// fix

BAPromise *promise = [self methodThatReturnsAPromise];
[promise then:^id(id obj) {
    NSLog(@"1st");
    return obj;
}];
[promise then:^id(id obj) {
    NSLog(@"2nd");
    BAPromise *promise2 = [[self otherMethodThatReturnsAPromise] then:^id(id obj) {
        NSLog(@"3rd");
        return obj;
    }];
    [promise2 done:^(id obj) {
        NSLog(@"4th");
    }];
    return promise2;
}];