Idea: make DisposeBag a noncopyable type in RxSwift 7

[nikolaykasyanov]

As far as my experience goes, dispose bags are usually attached to a single object's lifetime and (are supposted to) deinit with it.

Making DisposeBag a noncopyable type enforce this 1:1 relation and will prevent potential misuses, like passing DisposeBag around and retaining it somewhere accidentally, at compile time.

The obvious downside is code churn associated with it, because:

• all dispose bags will have to be var to be usable (unless all disposables are passed once on bag's creation)
• .disposed(by: bag) calls will have to become .disposed(by: &bag)
  But the above seems acceptable for a major release.

I'd appreciate your opinions and use cases that I didn't mention that may become problematic with DisposeBag being noncopyable.

PoC: #2634.

[freak4pc]

Hey there -

It's an interesting discussion which I've considered but indeed making them mutable and inout is a large change.
Worse than that, it will force us to support min Swift 5.9 - which might be fine for iOS, etc, but not fine for Unix/Linux etc.

The change doesn't seem valuable enough to me for its related costs. At least my personal opinion around this.

[nikolaykasyanov]

@freak4pc thanks for your feedback!

Btw, it looks like the mutability/inout argument can be avoided if the implementation is kept as it is in POC now, where a noncopyable struct uses a class instance under the hood. The reason I added mutating modifiers is to make it build against Xcode 15.4 (it wasn't liking func insert(_ disposables: [Disposable]) not being mutating). Requiring Xcode 16, however, will raise the required Swift version even further.

[freak4pc]

Right, totally understand -
I think that if the value was extremely high it would be worth considering, but as-is, the value vs. "payment" isn't balanced enough, so don't think can happen.

LMK if you feel comfortable closing this for now.

[nikolaykasyanov]

@freak4pc fair enough, I'm fine closing it.