Tracking issue for pin-project 0.4 #21

taiki-e · 2019-08-05T04:23:25Z

Current prerelease: 0.4.0-beta.1

The most important fix of this release is that pin projection has become a safe operation (#18, thanks @Aaron1011)

Changes

#[unsafe_project] has been replaced with #[pin_project]. (Replace unsafe_project with safe pin_projectable attribute #18, Remove pin_project! macro and add #[pinned_drop] attribute #33)
The Unpin argument has been removed - an Unpin impl is now generated by default. (Replace unsafe_project with safe pin_projectable attribute #18)
Drop impls must be specified with #[pinned_drop] attribute instead of via a normal Drop impl. (Replace unsafe_project with safe pin_projectable attribute #18, Remove pin_project! macro and add #[pinned_drop] attribute #33, Change #[pinned_drop] to trait implementation #86)
Unpin impls must be specified with an impl of UnsafeUnpin, instead of implementing the normal Unpin trait. (Replace unsafe_project with safe pin_projectable attribute #18)
~~Changed project method generated by #[pin_project] attribute to take an &mut Pin<&mut Self> argument. (Make generated 'project' reference take an '&mut Pin<&mut Self>' #47)~~ EDIT: reverted in Change the argument type of project method back to self: Pin<&mut Self> #90
Removed "project_attr" feature and always enable #[project] attribute (Remove "project_attr" feature and always enable #[project] attribute #94)
#[project] attribute can now be used for impl blocks. (Add impl block support to #[project] attribute #46)
#[project] attribute can now be used for use statements. (Add use statements support to #[project] attribute #85)
~~Made #[project] attribute disabled by default. (Should #[project] attribute be disabled by default? #36, Make #[project] attribute disabled by default #41)~~ EDIT: replaced with Remove "project_attr" feature and always enable #[project] attribute #94
Added project_ref method and #[project_ref] attribute. (Add project_ref method and #[project_ref] attribute #93)
#[pin_project] attribute now determines the visibility of the projection type/method is based on the original type. (Determine the visibility based on the original type #96)

TODO

Some adjustments are needed.

Make error message more obvious (Replace unsafe_project with safe pin_projectable attribute #18 (comment)); done in Cleanup #22
unsafe_Unpin vs UnsafeUnpin vs unsafe_unpin (Replace unsafe_project with safe pin_projectable attribute #18 (comment)); done in Change 'unsafe_Unpin' to UpperCamelCase (UnsafeUnpin) #40 (Adopted UnsafeUnpin).
Update proc-macro2, syn, and quote to 1.0; done in Update proc-macro2, syn, and quote to 1.0 #23
~~Test code examples in README (Test code examples in README #19)~~ EDIT: see Test code examples in README #19 (comment)
Mention Can bypass repr(packed) checking by hiding it in a proc-macro-attribute #32 in the documents; done in Ensure that #[repr(packed)] cannot be used on #[pin_projectable] structs #34
pin-project does not interoperate well with #[cfg()] (pin-project does not interoperate well with #[cfg()] #68)

Unresolved issues

Different approach to Unpin vs Drop (Weirdly different approach to Unpin vs Drop #26); done in Change #[pinned_drop] to trait implementation #86
Change the argument type of project method back to self: Pin<&mut Self> (Change the argument type of project method back to self: Pin<&mut Self> #89)

Blockers

~~Whether or not self: &mut Pin<&mut Self> stabilizes in Rust 1.39 (Stabilize nested self receivers in 1.41.0 rust-lang/rust#64325)~~ EDIT: replaced with Change the argument type of project method back to self: Pin<&mut Self> #89
Rustdoc issues (will be fixed in Improve Rustdoc's handling of procedural macros rust-lang/rust#62855); see Properly inline documentation and use intra-crate lints #98
1.0 release of proc-macro2, syn, and quote

I plan to have a few alpha releases before the blockers are resolved.

The text was updated successfully, but these errors were encountered:

taiki-e · 2019-08-06T08:53:35Z

I don't list it as a blocker, but rust-lang/rust#63281 is one of the issues to consider.

Aaron1011 · 2019-08-10T17:10:39Z

Mention #32 in the documents can be checked off/removed, now that the issue is closed.

taiki-e · 2019-08-10T17:13:53Z

@Aaron1011 thanks 👍

33: Remove pin_project! macro and add #[pinned_drop] attribute r=taiki-e a=taiki-e This removes `pin_project!` block and adds `#[pinned_drop]` attribute as proc-macro-attribute. If you want a custom `Drop` implementation, you need to pass the `PinnedDrop` argument to `pin_project` attribute instead of defining items in `pin_project!` block. In the previous implementation, `#[pinned_drop]` implemented `Drop` directly, but this PR changes it to implement this via a private unsafe trait method. Also, this renames `pin_projectable` to `pin_project`. cc #21, #26 Related: #18 (comment) ### Examples Before: ```rust use std::fmt::Debug; use pin_project::{pin_project, pin_projectable}; use std::pin::Pin; pin_project! { #[pin_projectable] pub struct Foo<T: Debug, U: Debug> { #[pin] pinned_field: T, unpin_field: U } #[pinned_drop] fn my_drop_fn<T: Debug, U: Debug>(foo: Pin<&mut Foo<T, U>>) { let foo = foo.project(); println!("Dropping pinned field: {:?}", foo.pinned_field); println!("Dropping unpin field: {:?}", foo.unpin_field); } } ``` After: ```rust use std::fmt::Debug; use pin_project::{pin_project, pinned_drop}; use std::pin::Pin; #[pin_project(PinnedDrop)] pub struct Foo<T: Debug, U: Debug> { #[pin] pinned_field: T, unpin_field: U } #[pinned_drop] fn my_drop_fn<T: Debug, U: Debug>(foo: Pin<&mut Foo<T, U>>) { let foo = foo.project(); println!("Dropping pinned field: {:?}", foo.pinned_field); println!("Dropping unpin field: {:?}", foo.unpin_field); } ``` ### TODO - [x] Update docs Co-authored-by: Taiki Endo <te316e89@gmail.com>

42: Release 0.4.0-alpha.1 r=taiki-e a=taiki-e [Changelog](https://github.com/taiki-e/pin-project/blob/1276ad933cf5f0b2aad98a0d38fd4cbe0634090e/CHANGELOG.md#040-alpha1---2019-08-11) cc #21 Co-authored-by: Taiki Endo <te316e89@gmail.com>

taiki-e · 2019-08-11T15:53:28Z

Published 0.4.0-alpha.1 (crate.io, releases, docs)!

13: Update pin-project to 0.4.0-alpha.1 r=taiki-e a=taiki-e Refs: taiki-e/pin-project#21 Co-authored-by: Taiki Endo <te316e89@gmail.com>

23: Update proc-macro2, syn, and quote to 1.0 r=taiki-e a=taiki-e cc #21 Co-authored-by: Taiki Endo <te316e89@gmail.com>

taiki-e · 2019-09-11T03:40:02Z

UPDATE: Replaced with #89

TR; DR: Added "Whether or not self: &mut Pin<&mut Self> stabilizes in Rust 1.39" (rust-lang/rust#64325) to blocker list.

rust-lang/rust#64325 stabilizes self: &mut Pin<&mut Self>.
This removes some of the hacks introduced in #47.
It can also solve some existing problems (e.g., tower-rs/tower#326 (comment)).

However, this means will take a different approach between versions prior to 1.39 and versions 1.39 or later. This should not break compatibility, but it will cause a feature that is "supported only with rust 1.39 or later". Specifically, it is a feature that "project/project_into method can be called outside the defined scope" that is planned to be provided by #80.

Also, if stabilization is delayed, the impact on crate using async / await (e.g., tower) is too big, so merge #80 to make those features available in versions 1.39 and earlier.

taiki-e · 2019-09-11T18:31:18Z

Resolved #26 and added "Change the argument type of project method back to self: Pin<&mut Self>" (#89) to unresolved issue list.

101: Release 0.4.0-beta.1 r=taiki-e a=taiki-e Changes: * [Changed the argument type of project method back to `self: Pin<&mut Self>`.][90] * [Removed "project_attr" feature and always enable `#[project]` attribute.][94] * [Removed "renamed" feature.][100] * [`#[project]` attribute can now be used for `use` statements.][85] * [Added `project_ref` method and `#[project_ref]` attribute.][93] * [`#[pin_project]` attribute now determines the visibility of the projection type/method is based on the original type.][96] cc #21 [85]: #85 [90]: #90 [93]: #93 [94]: #94 [96]: #96 [100]: #100 Co-authored-by: Taiki Endo <te316e89@gmail.com>

taiki-e · 2019-09-25T07:16:16Z

I have filed #107 to fix #102. Once #107 is merged, I will release 0.4.0. As documentation fixes are no breaking changes, will be fixed in the patch versions.

109: Release 0.4.0 r=taiki-e a=taiki-e cc #21 ### Changes since the latest 0.3 release: * **Pin projection has become a safe operation.** In the absence of other unsafe code that you write, it is impossible to cause undefined behavior. (#18) * `#[unsafe_project]` attribute has been replaced with `#[pin_project]` attribute. (#18, #33) * The `Unpin` argument has been removed - an `Unpin` impl is now generated by default. (#18) * Drop impls must be specified with `#[pinned_drop]` instead of via a normal `Drop` impl. (#18, #33, #86) * `Unpin` impls must be specified with an impl of `UnsafeUnpin`, instead of implementing the normal `Unpin` trait. (#18) * `#[pin_project]` attribute now determines the visibility of the projection type/method is based on the original type. (#96) * `#[pin_project]` can now be used for public type with private field types. (#53) * `#[pin_project]` can now interoperate with `#[cfg()]`. (#77) * Added `project_ref` method to `#[pin_project]` types. (#93) * Added `#[project_ref]` attribute. (#93) * Removed "project_attr" feature and always enable `#[project]` attribute. (#94) * `#[project]` attribute can now be used for `impl` blocks. (#46) * `#[project]` attribute can now be used for `use` statements. (#85) * `#[project]` attribute now supports `match` expressions at the position of the initializer expression of `let` expressions. (#51) ### Changes since the 0.4.0-beta.1 release: * Fixed an issue that caused an error when using `#[pin_project(UnsafeUnpin)]` and not providing a manual `UnsafeUnpin` implementation on a type with no generics or lifetime. (#107) Co-authored-by: Taiki Endo <te316e89@gmail.com>

taiki-e · 2019-09-25T16:46:56Z

Published 0.4.0. Thanks everybody for your contribution and feedback (especially @Aaron1011!).

taiki-e added this to the v0.4 milestone Aug 5, 2019

taiki-e self-assigned this Aug 5, 2019

taiki-e pinned this issue Aug 5, 2019

taiki-e mentioned this issue Aug 5, 2019

Update proc-macro2, syn, and quote to 1.0 #23

Merged

This was referenced Aug 6, 2019

Remove pin_project! macro and add #[pinned_drop] attribute #33

Merged

[WIP] Add the pin_project attribute #12

Closed

[WIP] Use pin-project instead of unsafe_[un]pinned rust-lang/futures-rs#1616

Closed

taiki-e mentioned this issue Aug 11, 2019

Release 0.4.0-alpha.1 #42

Merged

taiki-e mentioned this issue Aug 11, 2019

Update pin-project to 0.4.0-alpha.1 taiki-e/futures-async-stream#13

Merged

bors bot added a commit to taiki-e/futures-async-stream that referenced this issue Aug 11, 2019

Merge #13

ab64531

13: Update pin-project to 0.4.0-alpha.1 r=taiki-e a=taiki-e Refs: taiki-e/pin-project#21 Co-authored-by: Taiki Endo <te316e89@gmail.com>

bors bot added a commit that referenced this issue Aug 13, 2019

Merge #23

c9e62cc

23: Update proc-macro2, syn, and quote to 1.0 r=taiki-e a=taiki-e cc #21 Co-authored-by: Taiki Endo <te316e89@gmail.com>

taiki-e mentioned this issue Sep 5, 2019

pin-project does not interoperate well with #[cfg()] #68

Closed

taiki-e mentioned this issue Sep 21, 2019

Release 0.4.0-beta.1 #101

Merged

taiki-e added the A-meta label Sep 24, 2019

taiki-e added C-tracking-Issue and removed A-meta labels Sep 25, 2019

taiki-e added A-meta and removed A-meta labels Sep 25, 2019

taiki-e mentioned this issue Sep 25, 2019

Release 0.4.0 #109

Merged

taiki-e closed this as completed Sep 25, 2019

taiki-e unpinned this issue Sep 25, 2019

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Tracking issue for pin-project 0.4 #21

Tracking issue for pin-project 0.4 #21

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Tracking issue for pin-project 0.4 #21

Tracking issue for pin-project 0.4 #21

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