Stabilize -Zfeatures and -Zpackage-features. #8997

ehuss · 2020-12-18T17:14:37Z

This follows through with RFC 2957 to stabilize the new feature resolver, and -Zpackage-features command-line changes.

This also rewrites the "Features" chapter to try to expand it a little.

I decided to leave the -Zfeatures flag in for now for testing, but it can be removed at a later date.

There is a code change related to the package-name/feature-name syntax for the --features flag. I wanted to stabilize that for resolver = "1", but I previously neglected to separate that behavior out, so it required change to Workspace::members_with_features to make that work (see the resolver1_member_features test).

Closes #4328
Closes #5364
Closes #7914
Closes #7915
Closes #7916
Closes #8088
Closes #8431

rust-highfive · 2020-12-18T17:14:41Z

r? @alexcrichton

(rust-highfive has picked a reviewer for you, use r? to override)

ehuss · 2020-12-18T17:14:59Z

I would like to delay merging this until after the beta branch next week (Friday 12/25). I would like to make sure it has the full 12 weeks for testing, and to avoid any rushes for problems over the holidays.

alexcrichton

Awesome and thanks so much for this! I think the new features chapter is getting a much needed rewrite and I like how it all reads and the information covered there. I didn't see that it would clearly fill any missing gaps in the documentation, but another crate which could serve as an example usage of features is web-sys which controls compile-time with features. This is very similar and less-well-known than winapi, however.

One thing I'd like to see is defaulting to resolver = "2" for new manifests, but presumably that will need to wait until this stabilization hits stable at least? (otherwise cargo +nightly new'd projects aren't buildable on stable)

alexcrichton · 2020-12-18T21:16:57Z

src/doc/src/reference/features-examples.md

+allowing extended capabilities for platforms that support the full standard
+library. The [`memchr`] package defines a [`std` feature] that is [enabled by
+default][memchr-default]. At the top of the library, it [conditionally enables
+the `no_std` attribute][memchr-nostd]. Then, in various places in the code, it


Technically I would not recommend this design to others (a conditional #![no_std] attribute), because it's generally easier to develop libraries if they unconditionally define the attribute and conditionally import std based on features. Then if items from std are desired they are imported in the relevant locations with use std::... (etc)

alexcrichton · 2020-12-18T21:22:34Z

src/doc/src/reference/features.md


+```toml
+[features]
+default = ["bmp", "png", "ico", "webp"]


Should this perhaps omit bmp and png to show that feature are recursively enabled?

alexcrichton · 2020-12-18T21:25:38Z

src/doc/src/reference/features.md

+
+> **Note**: Sometimes feature unification may be a little too aggressive. See
+> the `resolver = "2"` option [described below](#feature-resolver-version-2)
+> for improved behavior.


I think it might be better to not mention this here since this will soon become the default for almost everyone?

alexcrichton · 2020-12-18T21:26:37Z

src/doc/src/reference/features.md

+  >
+  > In this situation, features "foo" and "bar" are enabled on the given
+  > members only if the member defines that feature. It is an error if none of
+  > the selected packages defines a given feature.


I'm a bit on the fence about the inline notes here about resolver=1/2. I find them useful personally but as the ecosystem shifts more and more to =2 then these notes will largely become clutter. Perhaps this chapter could be written from the perspective of a year from now with notes about resolver=1 at the end?

Sure! That's something I struggle with in the Rust reference, too, trying to describe multiple editions at the same time. I removed the notes, since they were essentially just duplicating the same information, and aren't that important. I think in the future when "2" is the default, it can be tweaked some more.

alexcrichton · 2020-12-18T21:27:36Z

src/doc/src/reference/features.md

+`std`. For example:
+
+```rust
+#![cfg_attr(not(feature = "std"), no_std)]


In the spirit of additiveness, I think it'd be better to show here the unconditional #![no_std] followed by a conditional use std::... perhaps?

bors · 2020-12-19T15:58:45Z

☔ The latest upstream changes (presumably #8987) made this pull request unmergeable. Please resolve the merge conflicts.

Note that reviewers usually do not review pull requests until merge conflicts are resolved! Once you resolve the conflicts, you should change the labels applied by bors to indicate that your PR is ready for review. Post this as a comment to change the labels:

@rustbot modify labels: +S-waiting-on-review -S-waiting-on-author

ehuss · 2020-12-19T17:17:29Z

One thing I'd like to see is defaulting to resolver = "2" for new manifests, but presumably that will need to wait until this stabilization hits stable at least?

Yea, per https://github.com/rust-lang/rfcs/blob/master/text/2957-cargo-features2.md#default-cargo-new I'd like to wait for it to be on stable for while, and to see how widespread the breakage will be in practice.

rimutaka · 2020-12-20T20:48:57Z

src/doc/src/reference/features.md

+There are rare cases where features may be mutually incompatible with one
+another. This should be avoided if at all possible, because it requires
+coordinating all uses of the package in the dependency graph to cooperate to
+avoid enabling them together. If it is not possible, consider adding a compile


rustls vs openssl come to mind as example here

rimutaka

If this level of detail was available in the docs few months ago when I started learning rust it would save me a lot of time. I think this is a major improvement.

rimutaka · 2020-12-20T21:02:31Z

src/doc/src/reference/features.md

+the command-line with `-p` flags. For example:
+
+```sh
+# This command is now allowed, regardless of which directory you are in.


Using "now" sets the frame of temporal reference and will look odd when there is v.2.x or some later version. Would it be better to use direct version references, e.g. "This command is allowed in resolver 2" / "not allowed in resolver 1"? There are a few other places in the text where "now", "previously" and "new" are used in a similar way. This is really nit-picking on my side, sorry.

rimutaka · 2020-12-20T21:06:44Z

src/doc/src/reference/features.md

+build dependencies are always built separately from normal dependencies in
+that scenario.
+
+The `resolver = "2"` setting also changes the behavior of the `--features` and


I had to re-read this paragraph a few times to grasp it.

rimutaka · 2020-12-20T21:13:34Z

src/doc/src/reference/features.md

+
+[`cargo tree`]: ../commands/cargo-tree.md
+
+### Feature resolver version 2


I wonder if subheadings would help make this section more comprehensible.

rimutaka · 2020-12-20T21:26:24Z

src/doc/src/reference/features.md

+
+### Feature documentation and discovery
+
+You are encouraged to document which features are available in your package.


How do I document features? Should it be followed by the sentence from line 444?

rimutaka · 2020-12-20T21:31:05Z

src/doc/src/reference/features.md

+[cargo-remove-opt-dep]: semver.md#cargo-remove-opt-dep
+[cargo-feature-remove-another]: semver.md#cargo-feature-remove-another
+
+### Feature documentation and discovery


Most users are on the discovery side, but this section mainly talks about documenting features.

What if a feature is not documented? How do I find out about it? The discovery used to be a stumbling block for me. Now I just go straight for Cargo.toml and then search for cfg with the feature name in the code to see what it does. There may be a better way, though. Mentioning some of these shortcuts may help a novice user.

rimutaka · 2020-12-20T21:45:32Z

tests/testsuite/features2.rs

 use std::fs::File;

+/// Switches Cargo.toml to use `resolver = "2"`.
+pub fn switch_to_resolver_2(p: &Project) {


I wonder if there is a serializer/deserializer to avoid string manipulations.

* Avoid terms like "new", "previously", and "now". * Add link for `resolver` field in manifest.md. * Move the resolver version specification to the resolver chapter. * Break up the version 2 section in features.md into subsections. * Try to clarify some of the wording, and make it clearer when talking about resolver versions. * Rewrite the section on version 2 command-line flags to hopefully be clearer.

Trying to make it clearer and expand on how to document.

ehuss · 2020-12-21T19:39:01Z

Thanks for the feedback @rimutaka! I pushed some changes to rewrite some of the sections you mentioned.

rimutaka · 2020-12-21T22:01:12Z

@ehuss Eric, I reckon it looks pretty good. Feel free to tag me if you need any more help with this or other issues.

Update cargo 12 commits in 75d5d8cffe3464631f82dcd3c470b78dc1dda8bb..329895f5b52a358e5d9ecb26215708b5cb31d906 2020-12-22 18:10:56 +0000 to 2021-01-06 00:01:52 +0000 - metadata: Supply local path for path dependencies (rust-lang/cargo#8994) - Add support for Rust edition 2021. (rust-lang/cargo#8922) - Stabilize -Zfeatures and -Zpackage-features. (rust-lang/cargo#8997) - Small refactor, adding a list of all kinds to BuildContext (rust-lang/cargo#9046) - Fix git http.proxy config setting. (rust-lang/cargo#8986) - Clarify the help text of `--aggressive` and `--precise` of `update` (rust-lang/cargo#9031) - Assert that tests are run in the crate directory (rust-lang/cargo#9037) - Update mdbook (rust-lang/cargo#9044) - Bump to 0.52.0, update changelog (rust-lang/cargo#9042) - Fix redundant semicolon. (rust-lang/cargo#9033) - Clarify fingerprint log messages (rust-lang/cargo#9026) - Update credential docs for gnome-secret. (rust-lang/cargo#9013)

311: Remove unstable package-features after stabilization r=jethrogb a=Goirad Remove `-Z package-features` from the Travis CI config after its stabilization with rust-lang/cargo#8997 Co-authored-by: Dario Gonzalez <[email protected]>

It was stabilized by <rust-lang/cargo#8997>.

Fix --feature pkg/feat for V1 resolver for non-member. #8997 had an unintended regression where `-p foo --feature foo/feat` syntax where `foo` is an **optional non-member** fails with an error that `foo` did not match any packages. The issue is that the member/feature selection routine needed to slot this into the features for the package in the current working directory (it was incorrectly treating `foo` as a workspace member). V2 outright does not allow specifying features for non-workspace members. Fixes #9265

Fix --feature pkg/feat for V1 resolver for non-member. rust-lang#8997 had an unintended regression where `-p foo --feature foo/feat` syntax where `foo` is an **optional non-member** fails with an error that `foo` did not match any packages. The issue is that the member/feature selection routine needed to slot this into the features for the package in the current working directory (it was incorrectly treating `foo` as a workspace member). V2 outright does not allow specifying features for non-workspace members. Fixes rust-lang#9265

Pkgsrc changes: * Remove one SunOS patch, apparently no longer needed. * Adapt one patch for Darwin, adjust cargo checksum accordingly. * Adjust bootstraps to version 1.50.0. Version 1.51.0 (2021-03-25) ============================ Language -------- - [You can now parameterize items such as functions, traits, and `struct`s by constant values in addition to by types and lifetimes.][79135] Also known as "const generics" E.g. you can now write the following. Note: Only values of primitive integers, `bool`, or `char` types are currently permitted. ```rust struct GenericArray<T, const LENGTH: usize> { inner: [T; LENGTH] } impl<T, const LENGTH: usize> GenericArray<T, LENGTH> { const fn last(&self) -> Option<&T> { if LENGTH == 0 { None } else { Some(&self.inner[LENGTH - 1]) } } } ``` Compiler -------- - [Added the `-Csplit-debuginfo` codegen option for macOS platforms.][79570] This option controls whether debug information is split across multiple files or packed into a single file. **Note** This option is unstable on other platforms. - [Added tier 3\* support for `aarch64_be-unknown-linux-gnu`, `aarch64-unknown-linux-gnu_ilp32`, and `aarch64_be-unknown-linux-gnu_ilp32` targets.][81455] - [Added tier 3 support for `i386-unknown-linux-gnu` and `i486-unknown-linux-gnu` targets.][80662] - [The `target-cpu=native` option will now detect individual features of CPUs.][80749] - [Rust now uses `inline-asm` for stack probes when used with LLVM 11.0.1+][77885] \* Refer to Rust's [platform support page][forge-platform-support] for more information on Rust's tiered platform support. Libraries --------- - [`Box::downcast` is now also implemented for any `dyn Any + Send + Sync` object.][80945] - [`str` now implements `AsMut<str>`.][80279] - [`u64` and `u128` now implement `From<char>`.][79502] - [`Error` is now implemented for `&T` where `T` implements `Error`.][75180] - [`Poll::{map_ok, map_err}` are now implemented for `Poll<Option<Result<T, E>>>`.][80968] - [`unsigned_abs` is now implemented for all signed integer types.][80959] - [`io::Empty` now implements `io::Seek`.][78044] - [`rc::Weak<T>` and `sync::Weak<T>`'s methods such as `as_ptr` are now implemented for `T: ?Sized` types.][80764] Stabilized APIs --------------- - [`Arc::decrement_strong_count`] - [`Arc::increment_strong_count`] - [`Once::call_once_force`] - [`Peekable::next_if_eq`] - [`Peekable::next_if`] - [`Seek::stream_position`] - [`array::IntoIter`] - [`panic::panic_any`] - [`ptr::addr_of!`] - [`ptr::addr_of_mut!`] - [`slice::fill_with`] - [`slice::split_inclusive_mut`] - [`slice::split_inclusive`] - [`slice::strip_prefix`] - [`slice::strip_suffix`] - [`str::split_inclusive`] - [`sync::OnceState`] - [`task::Wake`] Cargo ----- - [Added the `split-debuginfo` profile option to control the -Csplit-debuginfo codegen option.][cargo/9112] - [Added the `resolver` field to `Cargo.toml` to enable the new feature resolver and CLI option behavior.][cargo/8997] Version 2 of the feature resolver will try to avoid unifying features of dependencies where that unification could be unwanted. Such as using the same dependency with a `std` feature in a build scripts and proc-macros, while using the `no-std` feature in the final binary. See the [Cargo book documentation][[email protected]] for more information on the feature. Rustdoc ------- - [Rustdoc will now include documentation for methods available from `Deref` traits.][80653] - [You can now provide a `--default-theme` flag which sets the default theme to use for documentation.][79642] Various improvements to intra-doc links: - [You can link to non-path primitives such as `slice`.][80181] - [You can link to associated items.][74489] - [You can now include generic parameters when linking to items, like `Vec<T>`.][76934] Misc ---- - [You can now pass `--include-ignored` to tests (e.g. with `cargo test -- --include-ignored`) to include testing tests marked `#[ignore]`.][80053] Compatibility Notes ------------------- - [WASI platforms no longer use the `wasm-bindgen` ABI, and instead use the wasm32 ABI.][79998] - [`rustc` no longer promotes division, modulo and indexing operations to `const` that could fail.][80579] - [The minimum version of glibc for the following platforms has been bumped to version 2.31 for the distributed artifacts.][81521] - `armv5te-unknown-linux-gnueabi` - `sparc64-unknown-linux-gnu` - `thumbv7neon-unknown-linux-gnueabihf` - `armv7-unknown-linux-gnueabi` - `x86_64-unknown-linux-gnux32` Internal Only ------------- - [Consistently avoid constructing optimized MIR when not doing codegen][80718] [79135]: rust-lang/rust#79135 [74489]: rust-lang/rust#74489 [76934]: rust-lang/rust#76934 [79570]: rust-lang/rust#79570 [80181]: rust-lang/rust#80181 [79642]: rust-lang/rust#79642 [80945]: rust-lang/rust#80945 [80279]: rust-lang/rust#80279 [80053]: rust-lang/rust#80053 [79502]: rust-lang/rust#79502 [75180]: rust-lang/rust#75180 [79135]: rust-lang/rust#79135 [81521]: rust-lang/rust#81521 [80968]: rust-lang/rust#80968 [80959]: rust-lang/rust#80959 [80718]: rust-lang/rust#80718 [80653]: rust-lang/rust#80653 [80579]: rust-lang/rust#80579 [79998]: rust-lang/rust#79998 [78044]: rust-lang/rust#78044 [81455]: rust-lang/rust#81455 [80764]: rust-lang/rust#80764 [80749]: rust-lang/rust#80749 [80662]: rust-lang/rust#80662 [77885]: rust-lang/rust#77885 [cargo/8997]: rust-lang/cargo#8997 [cargo/9112]: rust-lang/cargo#9112 [[email protected]]: https://doc.rust-lang.org/nightly/cargo/reference/features.html#feature-resolver-version-2 [`Once::call_once_force`]: https://doc.rust-lang.org/stable/std/sync/struct.Once.html#method.call_once_force [`sync::OnceState`]: https://doc.rust-lang.org/stable/std/sync/struct.OnceState.html [`panic::panic_any`]: https://doc.rust-lang.org/stable/std/panic/fn.panic_any.html [`slice::strip_prefix`]: https://doc.rust-lang.org/stable/std/primitive.slice.html#method.strip_prefix [`slice::strip_suffix`]: https://doc.rust-lang.org/stable/std/primitive.slice.html#method.strip_prefix [`Arc::increment_strong_count`]: https://doc.rust-lang.org/nightly/std/sync/struct.Arc.html#method.increment_strong_count [`Arc::decrement_strong_count`]: https://doc.rust-lang.org/nightly/std/sync/struct.Arc.html#method.decrement_strong_count [`slice::fill_with`]: https://doc.rust-lang.org/nightly/std/primitive.slice.html#method.fill_with [`ptr::addr_of!`]: https://doc.rust-lang.org/nightly/std/ptr/macro.addr_of.html [`ptr::addr_of_mut!`]: https://doc.rust-lang.org/nightly/std/ptr/macro.addr_of_mut.html [`array::IntoIter`]: https://doc.rust-lang.org/nightly/std/array/struct.IntoIter.html [`slice::split_inclusive`]: https://doc.rust-lang.org/nightly/std/primitive.slice.html#method.split_inclusive [`slice::split_inclusive_mut`]: https://doc.rust-lang.org/nightly/std/primitive.slice.html#method.split_inclusive_mut [`str::split_inclusive`]: https://doc.rust-lang.org/nightly/std/primitive.str.html#method.split_inclusive [`task::Wake`]: https://doc.rust-lang.org/nightly/std/task/trait.Wake.html [`Seek::stream_position`]: https://doc.rust-lang.org/nightly/std/io/trait.Seek.html#method.stream_position [`Peekable::next_if`]: https://doc.rust-lang.org/nightly/std/iter/struct.Peekable.html#method.next_if [`Peekable::next_if_eq`]: https://doc.rust-lang.org/nightly/std/iter/struct.Peekable.html#method.next_if_eq

Pkgsrc changes: * Add support for the big-endian arm64 NetBSD target (aarch64_be). * On NetBSD/i386, use the i586 (pentium) bootstrap kit variant in preference to i686. * Adjust patches, re-compute line offsets, re-compute crate checksums. * Remove a patch which was either integrated upstream and/or no longer applies. * Bump bootstraps to 1.50.0. * Move conditionals until after bsd.prefs.mk so that they work... * Default to "dist" build target if cross-compiling, but allow also to override via rust.BUILD_TARGET. * Allow overriding MAKE_JOBS_SAFE via rust.MAKE_JOBS_SAFE if you want a different trade-off between occasional breakage and performance. * Adjust platform.mk according to work already done in wip/rust/ * Add a patch to optimize the install.sh script used to install binary bootstraps to not do so many forks; use case/esac and parameter expansion instead of grep, sed and cut. * Drop building documentation for the binary bootstrap kits. This will also impact the lang/rust-bin package. For full documentation, build or install lang/rust as a package. Upstream changes: Version 1.51.0 (2021-03-25) ============================ Language -------- - [You can now parameterize items such as functions, traits, and `struct`s by constant values in addition to by types and lifetimes.][79135] Also known as "const generics" E.g. you can now write the following. Note: Only values of primitive integers, `bool`, or `char` types are currently permitted. ```rust struct GenericArray<T, const LENGTH: usize> { inner: [T; LENGTH] } impl<T, const LENGTH: usize> GenericArray<T, LENGTH> { const fn last(&self) -> Option<&T> { if LENGTH == 0 { None } else { Some(&self.inner[LENGTH - 1]) } } } ``` Compiler -------- - [Added the `-Csplit-debuginfo` codegen option for macOS platforms.][79570] This option controls whether debug information is split across multiple files or packed into a single file. **Note** This option is unstable on other platforms. - [Added tier 3\* support for `aarch64_be-unknown-linux-gnu`, `aarch64-unknown-linux-gnu_ilp32`, and `aarch64_be-unknown-linux-gnu_ilp32` targets.][81455] - [Added tier 3 support for `i386-unknown-linux-gnu` and `i486-unknown-linux-gnu` targets.][80662] - [The `target-cpu=native` option will now detect individual features of CPUs.][80749] \* Refer to Rust's [platform support page][platform-support-doc] for more information on Rust's tiered platform support. Libraries --------- - [`Box::downcast` is now also implemented for any `dyn Any + Send + Sync` object.][80945] - [`str` now implements `AsMut<str>`.][80279] - [`u64` and `u128` now implement `From<char>`.][79502] - [`Error` is now implemented for `&T` where `T` implements `Error`.][75180] - [`Poll::{map_ok, map_err}` are now implemented for `Poll<Option<Result<T,E>>>`.][80968] - [`unsigned_abs` is now implemented for all signed integer types.][80959] - [`io::Empty` now implements `io::Seek`.][78044] - [`rc::Weak<T>` and `sync::Weak<T>`'s methods such as `as_ptr` are now implemented for `T: ?Sized` types.][80764] - [`Div` and `Rem` by their `NonZero` variant is now implemented for all unsigned integers.][79134] Stabilized APIs --------------- - [`Arc::decrement_strong_count`] - [`Arc::increment_strong_count`] - [`Once::call_once_force`] - [`Peekable::next_if_eq`] - [`Peekable::next_if`] - [`Seek::stream_position`] - [`array::IntoIter`] - [`panic::panic_any`] - [`ptr::addr_of!`] - [`ptr::addr_of_mut!`] - [`slice::fill_with`] - [`slice::split_inclusive_mut`] - [`slice::split_inclusive`] - [`slice::strip_prefix`] - [`slice::strip_suffix`] - [`str::split_inclusive`] - [`sync::OnceState`] - [`task::Wake`] - [`VecDeque::range`] - [`VecDeque::range_mut`] Cargo ----- - [Added the `split-debuginfo` profile option to control the -Csplit-debuginfo codegen option.][cargo/9112] - [Added the `resolver` field to `Cargo.toml` to enable the new feature resolver and CLI option behavior.][cargo/8997] Version 2 of the feature resolver will try to avoid unifying features of dependencies where that unification could be unwanted. Such as using the same dependency with a `std` feature in a build scripts and proc-macros, while using the `no-std` feature in the final binary. See the [Cargo book documentation][[email protected]] for more information on the feature. Rustdoc ------- - [Rustdoc will now include documentation for methods available from _nested_ `Deref` traits.][80653] - [You can now provide a `--default-theme` flag which sets the default theme to use for documentation.][79642] Various improvements to intra-doc links: - [You can link to non-path primitives such as `slice`.][80181] - [You can link to associated items.][74489] - [You can now include generic parameters when linking to items, like `Vec<T>`.][76934] Misc ---- - [You can now pass `--include-ignored` to tests (e.g. with `cargo test -- --include-ignored`) to include testing tests marked `#[ignore]`.][80053] Compatibility Notes ------------------- - [WASI platforms no longer use the `wasm-bindgen` ABI, and instead use the wasm32 ABI.][79998] - [`rustc` no longer promotes division, modulo and indexing operations to `const` that could fail.][80579] - [The minimum version of glibc for the following platforms has been bumped to version 2.31 for the distributed artifacts.][81521] - `armv5te-unknown-linux-gnueabi` - `sparc64-unknown-linux-gnu` - `thumbv7neon-unknown-linux-gnueabihf` - `armv7-unknown-linux-gnueabi` - `x86_64-unknown-linux-gnux32` - [`atomic::spin_loop_hint` has been deprecated.][80966] It's recommended to use `hint::spin_loop` instead. Internal Only ------------- - [Consistently avoid constructing optimized MIR when not doing codegen][80718] [79135]: rust-lang/rust#79135 [74489]: rust-lang/rust#74489 [76934]: rust-lang/rust#76934 [79570]: rust-lang/rust#79570 [80181]: rust-lang/rust#80181 [79642]: rust-lang/rust#79642 [80945]: rust-lang/rust#80945 [80279]: rust-lang/rust#80279 [80053]: rust-lang/rust#80053 [79502]: rust-lang/rust#79502 [75180]: rust-lang/rust#75180 [79135]: rust-lang/rust#79135 [81521]: rust-lang/rust#81521 [80968]: rust-lang/rust#80968 [80959]: rust-lang/rust#80959 [80718]: rust-lang/rust#80718 [80653]: rust-lang/rust#80653 [80579]: rust-lang/rust#80579 [79998]: rust-lang/rust#79998 [78044]: rust-lang/rust#78044 [81455]: rust-lang/rust#81455 [80764]: rust-lang/rust#80764 [80749]: rust-lang/rust#80749 [80662]: rust-lang/rust#80662 [79134]: rust-lang/rust#79134 [80966]: rust-lang/rust#80966 [cargo/8997]: rust-lang/cargo#8997 [cargo/9112]: rust-lang/cargo#9112 [[email protected]]: https://doc.rust-lang.org/nightly/cargo/reference/features.html#feature-resolver-version-2 [`Once::call_once_force`]: https://doc.rust-lang.org/stable/std/sync/struct.Once.html#method.call_once_force [`sync::OnceState`]: https://doc.rust-lang.org/stable/std/sync/struct.OnceState.html [`panic::panic_any`]: https://doc.rust-lang.org/stable/std/panic/fn.panic_any.html [`slice::strip_prefix`]: https://doc.rust-lang.org/stable/std/primitive.slice.html#method.strip_prefix [`slice::strip_suffix`]: https://doc.rust-lang.org/stable/std/primitive.slice.html#method.strip_prefix [`Arc::increment_strong_count`]: https://doc.rust-lang.org/nightly/std/sync/struct.Arc.html#method.increment_strong_count [`Arc::decrement_strong_count`]: https://doc.rust-lang.org/nightly/std/sync/struct.Arc.html#method.decrement_strong_count [`slice::fill_with`]: https://doc.rust-lang.org/nightly/std/primitive.slice.html#method.fill_with [`ptr::addr_of!`]: https://doc.rust-lang.org/nightly/std/ptr/macro.addr_of.html [`ptr::addr_of_mut!`]: https://doc.rust-lang.org/nightly/std/ptr/macro.addr_of_mut.html [`array::IntoIter`]: https://doc.rust-lang.org/nightly/std/array/struct.IntoIter.html [`slice::split_inclusive`]: https://doc.rust-lang.org/nightly/std/primitive.slice.html#method.split_inclusive [`slice::split_inclusive_mut`]: https://doc.rust-lang.org/nightly/std/primitive.slice.html#method.split_inclusive_mut [`str::split_inclusive`]: https://doc.rust-lang.org/nightly/std/primitive.str.html#method.split_inclusive [`task::Wake`]: https://doc.rust-lang.org/nightly/std/task/trait.Wake.html [`Seek::stream_position`]: https://doc.rust-lang.org/nightly/std/io/trait.Seek.html#method.stream_position [`Peekable::next_if`]: https://doc.rust-lang.org/nightly/std/iter/struct.Peekable.html#method.next_if [`Peekable::next_if_eq`]: https://doc.rust-lang.org/nightly/std/iter/struct.Peekable.html#method.next_if_eq [`VecDeque::range`]: https://doc.rust-lang.org/nightly/std/collections/struct.VecDeque.html#method.range [`VecDeque::range_mut`]: https://doc.rust-lang.org/nightly/std/collections/struct.VecDeque.html#method.range_mut

rust-highfive assigned alexcrichton Dec 18, 2020

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Add more examples with explanations to Ch 3.4. Features - help offered #8431

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Stabilize Cargo's new feature resolver rust-lang/rfcs#2957

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Blisto91 mentioned this pull request Dec 18, 2020

Autoselect Graphics Backend (no more --feature vulkan/metal/empty) amethyst/amethyst#2525

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alexcrichton reviewed Dec 18, 2020

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ilya-epifanov mentioned this pull request Dec 19, 2020

Parse without use of regex to work around dependency conflict ilya-epifanov/riscv-target#1

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ehuss mentioned this pull request Dec 19, 2020

Additional SemVer compatibility items. #8736

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41 tasks

ehuss added 6 commits December 19, 2020 08:26

Stabilize -Zfeatures and -Zpackage-features.

d087aeb

Don't use a conditional no_std attribute.

e17bfbb

Fix incorrect language tag.

5ee8ab1

Use recursive features in default example.

489248d

Add web-sys as an example.

9efa1ea

Remove resolver = "1" notes.

f731d25

ehuss force-pushed the stabilize-features branch from 9d2aba8 to f731d25 Compare December 19, 2020 17:16

rimutaka reviewed Dec 20, 2020

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CleanCut mentioned this pull request Dec 20, 2020

Why are bevy executable so large? bevyengine/bevy#1073

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rimutaka reviewed Dec 20, 2020

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ehuss added the relnotes Release-note worthy label Dec 21, 2020

ehuss added 2 commits December 21, 2020 11:02

Rewrite feature documentation section.

a500276

Trying to make it clearer and expand on how to document.

kennytm mentioned this pull request Dec 24, 2020

*: fix make build PROST=1 tikv/tikv#9358

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ehuss mentioned this pull request Dec 26, 2020

Document weak-dep-features in the features section as well #9015

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frewsxcv mentioned this pull request Jan 1, 2021

relative_eq() georust/geo#567

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bors merged commit 4aa5223 into rust-lang:master Jan 5, 2021

bors mentioned this pull request Jan 5, 2021

Add a --crate-type override to build and check. #8789

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ehuss mentioned this pull request Jan 6, 2021

Update cargo rust-lang/rust#80746

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daboross mentioned this pull request Jan 6, 2021

Replace native/web features with platform-specific dependencies once Rust 1.51.0 releases mrk-its/bevy_webgl2_app_template#5

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daboross mentioned this pull request Jan 7, 2021

Document that "features should be additive" #4328

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bkchr mentioned this pull request Jan 7, 2021

parity-scale-codec/derive enables serder/std even when std is not enabled paritytech/parity-scale-codec#204

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niklasad1 mentioned this pull request Jan 11, 2021

Migrate to Tokio 0.2 paritytech/jsonrpc#603

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mkroman mentioned this pull request Jan 11, 2021

Disable regex "perf" feature rust-cli/env_logger#181

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ordian mentioned this pull request Jan 12, 2021

ethereum-types: fix wasm builds for serialize feature paritytech/parity-common#503

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QuantumEntangledAndy mentioned this pull request Jan 14, 2021

Fix build and clippy actions norman784/gaiku#18

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niklasad1 mentioned this pull request Jan 14, 2021

Upgrade dependencies, bumps substrate to 2.0.1 paritytech/subxt#219

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Goirad mentioned this pull request Jan 14, 2021

Remove unstable package-features after stabilization fortanix/rust-sgx#311

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ryan-summers mentioned this pull request Jan 20, 2021

Adding support for reporting service information quartiq/booster#131

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yvt added a commit to r3-os/r3 that referenced this pull request Jan 31, 2021

chore: remove the -Zpackage-features option

a2d3e93

It was stabilized by <rust-lang/cargo#8997>.

AlexTMjugador mentioned this pull request Feb 1, 2021

Make cloudflare-zlib dependency optional shssoichiro/oxipng#369

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ehuss mentioned this pull request Feb 9, 2021

Update RELEASES.md for 1.51.0 rust-lang/rust#81917

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QuantumEntangledAndy mentioned this pull request Feb 16, 2021

Tests and benches norman784/gaiku#43

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Xanewok mentioned this pull request Feb 25, 2021

enable nightly features paritytech/cargo-unleash#38

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This was referenced Mar 15, 2021

cargo test --features dep/feat does not imply --features dep in beta #9265

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Fix --feature pkg/feat for V1 resolver for non-member. #9275

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Stabilize -Zfeatures and -Zpackage-features. #8997

Stabilize -Zfeatures and -Zpackage-features. #8997

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rimutaka commented Dec 21, 2020


		[`cargo tree`]: ../commands/cargo-tree.md

		### Feature resolver version 2


		### Feature documentation and discovery

		You are encouraged to document which features are available in your package.

Stabilize -Zfeatures and -Zpackage-features. #8997

Stabilize -Zfeatures and -Zpackage-features. #8997

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