futures 0.2 doesnt seem to be as stable as I thought

[web.git] / ralf / _posts / 2018-04-10-safe-intrusive-collections-with-pinning.md

diff --git a/ralf/_posts/2018-04-10-safe-intrusive-collections-with-pinning.md b/ralf/_posts/2018-04-10-safe-intrusive-collections-with-pinning.md
index 923480e4a3a8e8634861c8b264978cbaa3fa4fb0..37da65c29587937af3d87adee74655b5a10e39de 100644 (file)
--- a/ralf/_posts/2018-04-10-safe-intrusive-collections-with-pinning.md
+++ b/ralf/_posts/2018-04-10-safe-intrusive-collections-with-pinning.md
@@ -440,6 +440,7 @@ I hope we do not end up in a situation where `insert` with a shared reference is
 That just seems like the worst of both worlds.
 
 However, now we already have a [version of the futures crate](https://aturon.github.io/2018/04/06/futures2/) using the revised `Pin`, so I don't know if changing it again is realistic. :/
+(**Update:** Seems like [there may be breaking changes in future future versions anyway](https://www.reddit.com/r/rust/comments/8ac85w/futures_02_is_here/dwxkhvl/), so maybe the ship has not yet sailed after all. **/Update**)
 I feel bad about that.  Can we still fix this before everything gets stabilized?
 Others [have](https://github.com/rust-lang/rfcs/pull/2349#issuecomment-373206171) [argued](https://github.com/rust-lang/rfcs/pull/2349#issuecomment-378555691) for a shared pinned reference after it got removed from the API, and I argued against them as I did not understand how it could be useful.
 Thanks for not being convinced by me!
@@ -453,7 +454,7 @@ Removing `Pin::deref` (or restricting it to types that implement `Unpin`) would
 I spelled out the details [in the RFC issue](https://github.com/rust-lang/rfcs/pull/2349#issuecomment-372109981).
 So, if we want to declare that shared pinning is a typestate in its own right---which overall seems desirable---do we want it to be restricted like this due to an implementation detail of arbitrary self types?
 
-**Update:** @Diggsey [points out](https://github.com/rust-lang/rfcs/pull/2349#issuecomment-379230538) that we can still have a `PinRefCell` with a method like `fn get_pin(self: Pin<PinRefCell<T>>) -> Pin<T>`, as long as the `PinRefCell` never gives out mutable references. So it turns out that combining interior mutability and pinning should work fine, but having both pinned and unpinned interior mutability in the same type is where things start to go wrong due to `Pin::deref`.  **/Update**
+**Update:** @Diggsey [points out](https://github.com/rust-lang/rfcs/pull/2349#issuecomment-379230538) that we can still have a `PinRefCell` with a method like `fn get_pin(self: Pin<PinRefCell<T>>) -> Pin<T>`, as long as the `PinRefCell` never gives out mutable references. So it turns out that combining interior mutability and pinning should work fine.  Later, @glaebhoerl suggested we can even [combine `RefCell` and `PinRefCell` into one type if we dynamically track the pinning state](https://internals.rust-lang.org/t/safe-intrusive-collections-with-pinning/7281/11?u=ralfjung).  **/Update**
 
 ## 4 Conclusion
 
@@ -463,7 +464,6 @@ I am happy to learn that I was wrong!
 I am impressed by the creativity that went into coming up with these APIs, and looking forward to analyzing more of them in the future.
 
 The situation around shared pinning is still open, and it seems we need to have a discussion about what model we ultimately want to adopt---which code we ultimately want to be legal---and whether we want to change the `Pin` types before stabilization.
-Unfortunately I am four days late in my race against the [first significant user of this API](https://aturon.github.io/2018/04/06/futures2/).
 
 Anyway, as usual, please [let me know what you think](https://internals.rust-lang.org/t/safe-intrusive-collections-with-pinning/7281)!