Move automatic generation of Unpin implementation to proc-macro-derive #77

taiki-e · 2019-09-07T02:58:18Z

To generate the correct Unpin implementation, we need to collect the
types of the pinned fields. However, since proc-macro-attribute is
applied before cfg, we cannot be collecting field types at this timing.
So instead of generating the Unpin implementation here, we need to
delegate automatic generation of the Unpin implementation to
proc-macro-derive.

Fixes #68

taiki-e · 2019-09-07T02:59:14Z

compiletest.sh

@@ -0,0 +1,5 @@
+#!/bin/bash
+
+# A script to run compile tests with the same condition that pin-project executes with CI.


taiki-e · 2019-09-07T03:04:24Z

pin-project-internal/src/pin_project/enums.rs

-            proj_fields.push(quote!(#ident: ::core::pin::Pin<&#lifetime mut #ty>));
-            proj_body.push(quote!(#ident: ::core::pin::Pin::new_unchecked(#ident)));
+            proj_fields.push(quote! {
+                #(#cfg)* #ident: ::core::pin::Pin<&#lifetime mut #ty>


(In the future, it may be preferable to move these processes to proc-macro-derive.)

taiki-e · 2019-09-07T03:07:24Z

Hmm... tuple structs don't seem to work well either.

Edit:
https://doc.rust-lang.org/reference/attributes.html

Enum variants and struct and union fields accept outer attributes.

To generate the correct `Unpin` implementation, we need to collect the types of the pinned fields. However, since proc-macro-attribute is applied before cfg, we cannot be collecting field types at this timing. So instead of generating the `Unpin` implementation here, we need to delegate automatic generation of the `Unpin` implementation to proc-macro-derive.

We need to check this on proc-macro-derive because cfg may reduce the fields. On the other hand, if we check this only on proc-macro-derive, it may generate unhelpful error messages. So, we need to check this on both proc-macro-attribute and proc-macro-derive.

… attribute is applied

taiki-e · 2019-09-07T14:37:43Z

tests/ui/cfg/field_sneaky.rs

+use pin_project::pin_project;
+
+#[pin_project] //~ ERROR pattern does not mention field `__field`
+#[add_pinned_field]


I have never seen a crate actually attacked like this, but it should be preferable to be able to detect it.

taiki-e · 2019-09-07T16:28:45Z

bors r+

77: Move automatic generation of Unpin implementation to proc-macro-derive r=taiki-e a=taiki-e To generate the correct `Unpin` implementation, we need to collect the types of the pinned fields. However, since proc-macro-attribute is applied before cfg, we cannot be collecting field types at this timing. So instead of generating the `Unpin` implementation here, we need to delegate automatic generation of the `Unpin` implementation to proc-macro-derive. Fixes #68 Co-authored-by: Taiki Endo <te316e89@gmail.com>

bors · 2019-09-07T16:38:24Z

Build succeeded

taiki-e.pin-project

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>

135: Move most of the processing to proc-macro-derive r=taiki-e a=taiki-e To generate the correct `Unpin` implementation and the projection methods, we need to collect the types of the pinned fields. However, since proc-macro-attribute is applied before `#[cfg]` and `#[cfg_attr]` on fields, we cannot be collecting field types properly at this timing. So instead of generating the `Unpin` implementation and the projection methods here, delegate their processing to proc-macro-derive. #77 moved only the automatic generation of `Unpin` implementation to proc-macro-derive but found that it could not support `#[cfg_attr]`, so this moves more processing. See also #68 (comment). This also adds support for the use of `#[cfg]` on tuple structs and tuple variants. Closes #123 Co-authored-by: Taiki Endo <te316e89@gmail.com>

taiki-e added this to the v0.4 milestone Sep 7, 2019

taiki-e commented Sep 7, 2019

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taiki-e requested a review from Aaron1011 September 7, 2019 02:59

taiki-e commented Sep 7, 2019

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taiki-e force-pushed the fix-issue-68 branch 5 times, most recently from 36e5383 to a99ad13 Compare September 7, 2019 03:40

taiki-e mentioned this pull request Sep 7, 2019

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

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taiki-e force-pushed the fix-issue-68 branch from a99ad13 to cf5b0cb Compare September 7, 2019 03:44

taiki-e added 2 commits September 7, 2019 20:32

Prevent other proc macros from adding fields after the #[pin_project]…

5b09db5

… attribute is applied

taiki-e commented Sep 7, 2019

View reviewed changes

taiki-e force-pushed the fix-issue-68 branch from 2282f50 to 5b09db5 Compare September 7, 2019 15:05

taiki-e self-assigned this Sep 7, 2019

Merge enums.rs and struct.rs into attribute.rs

9e04e2a

taiki-e force-pushed the fix-issue-68 branch 2 times, most recently from 41eee20 to 6a8f202 Compare September 7, 2019 15:53

Add tests

fb8ebf4

taiki-e force-pushed the fix-issue-68 branch from 6a8f202 to fb8ebf4 Compare September 7, 2019 15:56

Update examples

6a0d419

bors bot merged commit 6a0d419 into master Sep 7, 2019

taiki-e deleted the fix-issue-68 branch September 7, 2019 16:39

jonhoo mentioned this pull request Sep 11, 2019

chore(dependencies): update pin-project to 0.4.0-alpha.10 hyperium/hyper#1935

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taiki-e mentioned this pull request Sep 25, 2019

Release 0.4.0 #109

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taiki-e mentioned this pull request Oct 13, 2019

Move most of the processing to proc-macro-derive #135

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taiki-e removed their assignment Oct 14, 2019

taiki-e added the A-pin-projection Area: #[pin_project] label Jun 4, 2020

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Move automatic generation of Unpin implementation to proc-macro-derive #77

Move automatic generation of Unpin implementation to proc-macro-derive #77

taiki-e commented Sep 7, 2019

taiki-e Sep 7, 2019

taiki-e Sep 7, 2019

taiki-e commented Sep 7, 2019 •

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taiki-e commented Sep 7, 2019

bors bot commented Sep 7, 2019

		@@ -0,0 +1,5 @@
		#!/bin/bash

		# A script to run compile tests with the same condition that pin-project executes with CI.

Move automatic generation of Unpin implementation to proc-macro-derive #77

Move automatic generation of Unpin implementation to proc-macro-derive #77

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