Fix unused configuration key warning for a few keys under `build`.
Recently cargo started to warn about configuration keys that he doesn't know about. However, there are a few keys under `build` that were used in a dynamic way (`rustc`, `rustdoc`, and `rustc_wrapper`) by `Config::maybe_get_tool()`.
Since these keys are not known to exist when `Config` is deserialized, cargo was emitting unused warnings.
This commit makes those config keys explicit. Note that by doing so there is a small breaking change: before it was possible to have `build.rustc_wrapper` in the configuration file (even though the documented key uses kebak-case), and now that key will be ignored. (Good thing we have warnings for unrecognized keys!)
Only include "already existing ..." comment in gitignore on conflict
I found the comment a bit confusing when I've used `cargo init` when I haven't had any conflicts. I thought it was meaning that my existing entries would be all commented out so I thought there was a bug of some kind.
This PR changes the comment to only be included when there are conflicting entries in the existing file.
Use multiple requirement syntax consistently
It was never super clear to me how I would specify multiple requirements since the page uses a "meta syntax" in most of the examples and only mention the real syntax in a single sentence. Now all version requirements on the page follow the same syntax.
Recently cargo started to warn about configuration keys that he doesn't know
about. However, there are a few keys under `build` that were used in a
dynamic way (`rustc`, `rustdoc`, and `rustc_wrapper`) by
`Config::maybe_get_tool()`.
Since these keys are not known to exist when `Config` is deserialized, cargo
was emitting unused warnings.
This commit makes those config keys explicit. Note that by doing so there is a
small breaking change: before it was possible to have `build.rustc_wrapper` in
the configuration file (even though the documented key uses kebak-case), and
now that key will be ignored. (Good thing we have warnings for unrecognized
keys!)
It was never super clear to me how I would specify multiple requirements since the page uses a "meta syntax" in most of the examples and only mention the real syntax in a single sentence. Now all version requirements on the page follow the same syntax.
Expand documentation on build scripts.
This restructures and adds some more documentation for writing build scripts. An overview:
- Move examples to a separate chapter.
- Add some links to common build dependencies.
- Rewrote the example of linking to system libraries.
- Rewrote some of the `links` and `-sys` examples.
- Added a "conditional compilation" example.
- De-emphasize setting `build = "build.rs"`.
- Explain how build scripts run.
- Give each `cargo:` instruction a separate section with more detail.
- More detail on how `rerun-if` stuff works. Also, try to emphasize best practices, especially in examples.
- Try to clarify `links` and go into more detail.
- Document the jobserver.
- Expand on environment variables.
- Document dylib search path behavior.
I have explicitly skipped trying to document rpath issues, as it seems to be a mess, and I can't really sort it out.
I'd be happy to have any feedback for things to add or change.
Closes#1251Closes#2236Closes#2888Closes#3304Closes#3968Closes#5499Closes#7338
Update crossbeam-utils requirement from 0.6 to 0.7
Updates the requirements on [crossbeam-utils](https://github.com/crossbeam-rs/crossbeam) to permit the latest version.
<details>
<summary>Changelog</summary>
*Sourced from [crossbeam-utils's changelog](https://github.com/crossbeam-rs/crossbeam/blob/master/CHANGELOG.md).*
> # Version 0.7.0
>
> - Remove `ArcCell`, `MsQueue`, and `TreiberStack`.
> - Change the interface of `ShardedLock` to match `RwLock`.
> - Add `SegQueue::len()`.
> - Rename `SegQueue::try_pop()` to `SegQueue::pop()`.
> - Change the return type of `SegQueue::pop()` to `Result`.
> - Introduce `ArrayQueue`.
> - Update dependencies.
>
> # Version 0.6.0
>
> - Update dependencies.
>
> # Version 0.5.0
>
> - Update `crossbeam-channel` to 0.3.
> - Update `crossbeam-utils` to 0.6.
> - Add `AtomicCell`, `SharedLock`, and `WaitGroup`.
>
> # Version 0.4.1
>
> - Fix a double-free bug in `MsQueue` and `SegQueue`.
>
> # Version 0.4
>
> - Switch to the new implementation of epoch-based reclamation in
> [`crossbeam-epoch`](https://github.com/crossbeam-rs/crossbeam-epoch), fixing numerous bugs in the
> old implementation. Its API is changed in a backward-incompatible way.
> - Switch to the new implementation of `CachePadded` and scoped thread in
> [`crossbeam-utils`](https://github.com/crossbeam-rs/crossbeam-utils). The scoped thread API is
> changed in a backward-incompatible way.
> - Switch to the new implementation of Chase-Lev deque in
> [`crossbeam-deque`](https://github.com/crossbeam-rs/crossbeam-deque). Its API is changed in a
> backward-incompatible way.
> - Export channel implemented in
> [`crossbeam-channel`](https://github.com/crossbeam-rs/crossbeam-channel).
> - Remove `AtomicOption`.
> - Implement `Default` and `From` traits.
>
> # Version 0.3
>
> - Introduced `ScopedThreadBuilder` with the ability to name threads and set stack size
> - `Worker` methods in the Chase-Lev deque don't require mutable access anymore
> - Fixed a bug when unblocking `pop()` in `MsQueue`
> - Implemented `Drop` for `MsQueue`, `SegQueue`, and `TreiberStack`
> - Implemented `Default` for `TreiberStack`
> - Added `is_empty` to `SegQueue`
> - Renamed `mem::epoch` to `epoch`
> - Other bug fixes
></tr></table> ... (truncated)
</details>
<details>
<summary>Commits</summary>
- [`28ad2b7`](28ad2b7e01) Update versions in readmes
- [`c98fea1`](c98fea12e6) Merge [#444](https://github-redirect.dependabot.com/crossbeam-rs/crossbeam/issues/444)
- [`d953f49`](d953f49ecc) Add compatibility section to readme
- [`c76f145`](c76f145182) Prepare for the next release
- [`99762ee`](99762ee633) Merge [#442](https://github-redirect.dependabot.com/crossbeam-rs/crossbeam/issues/442)
- [`ebb6b5f`](ebb6b5fe6d) Do not perform superfluous bounds checks on drop
- [`d2ab7a5`](d2ab7a5c43) Update LICENSE-APACHE
- [`f54db88`](f54db88d1a) Merge [#437](https://github-redirect.dependabot.com/crossbeam-rs/crossbeam/issues/437)
- [`caa52c4`](caa52c4e84) Merge [#436](https://github-redirect.dependabot.com/crossbeam-rs/crossbeam/issues/436)
- [`af68803`](af688031a2) Merge [#438](https://github-redirect.dependabot.com/crossbeam-rs/crossbeam/issues/438)
- Additional commits viewable in [compare view](https://github.com/crossbeam-rs/crossbeam/compare/crossbeam-utils-0.6.0...crossbeam-utils-0.7.0)
</details>
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Add --filter-platform to `cargo metadata`.
This adds the `--filter-platform` flag to `cargo metadata` to give users a way to filter the resolve information based on the target triple.
This is just a prototype to open for feedback. Some things that need feedback:
- Debate the name of the flag.
- It uses "host" as a special triple to mean the local host. Does that make sense? It seemed a little weird.
- Should it also filter the dependencies in the "packages" array? Right now it only does resolve. I'm on the fence. It probably should, but that would be an intrusive change to rewrite the Package values.
- Should the filtering be transitive? That is, if a package is only reachable by a specific platform, should it be removed from the resolve "nodes"? What about "packages"? Currently it is included, with the intent that you walk the resolve starting with a root (like a workspace member). But it might be surprising to see "winapi" when you filter for a unix platform.
This will need documentation before it is merged.
