Add missing "allocated object" doc link to `<*mut T>::add`
The portion of the documentation expecting the link was already there, but it was rendered as "[allocated object]". The added reference is just copied from the documentation for `<*const T>::add`.
rfc3052 followup: Remove authors field from Cargo manifests
Since RFC 3052 soft deprecated the authors field, hiding it from
crates.io, docs.rs, and making Cargo not add it by default, and it is
not generally up to date/useful information for contributors, we may as well
remove it from crates in this repo.
Recommend `swap_remove` in `Vec::remove` docs
I was able to increase the performance (by 20%!) of my project by changing a `Vec::remove` call to `Vec::swap_remove` in a hot function. I think we should explicitly put a note in the Vec::remove docs to guide people in the right direction so they don't make a similar oversight.
Add documentation for `Ipv6MulticastScope`
Adds basic documentation to the unstable `Ipv6MulticastScope`, as well as marking it `#[non_exhaustive]` because future IETF RFCs may introduce additional scopes. The documentation mentions this in a section "Stability Guarantees":
> /// Not all possible values for a multicast scope have been assigned.
/// Future RFCs may introduce new scopes, which will be added as variants to this enum;
/// because of this the enum is marked as `#[non_exhaustive]`.
Partially stabilize `const_slice_first_last`
This stabilizes the non-`mut` methods of `const_slice_first_last` as `const`. These methods are trivial to implement and have no blockers that I am aware of.
`@rustbot` label +A-const-fn +S-waiting-on-review +T-libs-api
Move `os_str_bytes` to `sys::unix`
Followup to #84967, with `OsStrExt` and `OsStringExt` moved out of `sys_common`, there is no reason anymore for `os_str_bytes` to live in `sys_common` and not in sys. This pr moves it to the location `sys::unix::os_str` and reuses the code on other platforms via `#[path]` (as is common in `sys`) instead of importing.
Remove `Ipv4Addr::is_ietf_protocol_assignment`
This PR removes the unstable method `Ipv4Addr::is_ietf_protocol_assignment`, as I suggested in https://github.com/rust-lang/rust/issues/85612#issuecomment-847863404. The method was added in #60145, as far as I can tell primarily for the implementation of `Ipv4Addr::is_global` (addresses reserved for IETF protocol assignment are not globally reachable unless otherwise specified).
The method was added in 2019, but I haven't been able to find any open-source code using this method so far. I'm also having a hard time coming up with a usecase for specifically this method; knowing that an address is reserved for future protocols doesn't allow you to do much with it, especially since now some of those addresses are indeed assigned to a protocol and have their own behaviour (and might even be defined to be globally reachable, so if that is what you care about it is always more accurate to call `!is_global()`, instead of `is_ietf_protocol_assignment()`).
Because of these reasons, I propose removing the method (or alternatively make it a private helper for `is_global`) and also not introduce `Ipv6Addr::is_ietf_protocol_assignment` and `IpAddr::is_ietf_protocol_assignment` in the future.
Change environment variable getters to error recoverably
This PR changes the standard library environment variable getter functions to error recoverably (i.e. not panic) when given an invalid value.
On some platforms, it is invalid for environment variable names to contain `'\0'` or `'='`, or for their values to contain `'\0'`. Currently, the standard library panics when manipulating environment variables with names or values that violate these invariants. However, this behavior doesn't make a lot of sense, at least in the case of getters. If the environment variable is missing, the standard library just returns an error value, rather than panicking. It doesn't make sense to treat the case where the variable is invalid any differently from that. See the [internals thread](https://internals.rust-lang.org/t/why-should-std-var-panic/14847) for discussion. Thus, this PR changes the functions to error recoverably in this case as well.
If desired, I could change the functions that manipulate environment variables in other ways as well. I didn't do that here because it wasn't entirely clear what to change them to. Should they error silently or do something else? If someone tells me how to change them, I'm happy to implement the changes.
This fixes#86082, an ICE that arises from the current behavior. It also adds a regression test to make sure the ICE does not occur again in the future.
`@rustbot` label +T-libs
r? `@joshtriplett`
BTree: lazily locate leaves in rangeless iterators
BTree iterators always locate both the first and last leaf edge and often only need either one, i.e., whenever they are traversed in a single direction, like in for-loops and in the common use of `iter().next()` or `iter().next_back()` to retrieve the first or last key/value-pair (#62924). It's fairly easy to avoid because the iterators with this disadvantage already are quite separate from other iterators.
r? `@Mark-Simulacrum`
Bump bootstrap compiler to 1.55
Changing the cfgs for stdarch is missing, but my understanding is that we don't need to do it as part of this PR?
r? `@Mark-Simulacrum`
Add Linux-specific pidfd process extensions (take 2)
Continuation of #77168.
I addressed the following concerns from the original PR:
- make `CommandExt` and `ChildExt` sealed traits
- wrap file descriptors in `PidFd` struct representing ownership over the fd
- add `take_pidfd` to take the fd out of `Child`
- close fd when dropped
Tracking Issue: #82971
Move UnwindSafe, RefUnwindSafe, AssertUnwindSafe to core
They were previously only available in std::panic, not core::panic.
- https://doc.rust-lang.org/1.51.0/std/panic/trait.UnwindSafe.html
- https://doc.rust-lang.org/1.51.0/std/panic/trait.RefUnwindSafe.html
- https://doc.rust-lang.org/1.51.0/std/panic/struct.AssertUnwindSafe.html
Where this is relevant: trait objects! Inside a `#![no_std]` library it's otherwise impossible to have a struct holding a trait object, and at the same time can be used from downstream std crates in a way that doesn't interfere with catch_unwind.
```rust
// common library
#![no_std]
pub struct Thing {
pub(crate) x: &'static (dyn SomeTrait + Send + Sync),
}
pub(crate) trait SomeTrait {...}
```
```rust
// downstream application
fn main() {
let thing: library::Thing = ...;
let _ = std::panic::catch_unwind(|| { let _ = thing; }); // does not work :(
}
```
See a4131708e2/src/gradient.rs (L7-L15) for a real life example of needing to work around this problem. In particular that workaround would not even be viable if implementors of the trait were provided externally by a caller, as the `feature = "std"` would become non-additive in that case.
What happens without the UnwindSafe constraints:
```rust
fn main() {
let gradient = colorous::VIRIDIS;
let _ = std::panic::catch_unwind(|| { let _ = gradient; });
}
```
```console
error[E0277]: the type `(dyn colorous::gradient::EvalGradient + Send + Sync + 'static)` may contain interior mutability and a reference may not be safely transferrable across a catch_unwind boundary
--> src/main.rs:3:13
|
3 | let _ = std::panic::catch_unwind(|| { let _ = gradient; });
| ^^^^^^^^^^^^^^^^^^^^^^^^ `(dyn colorous::gradient::EvalGradient + Send + Sync + 'static)` may contain interior mutability and a reference may not be safely transferrable across a catch_unwind boundary
|
::: .rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/std/src/panic.rs:430:40
|
430 | pub fn catch_unwind<F: FnOnce() -> R + UnwindSafe, R>(f: F) -> Result<R> {
| ---------- required by this bound in `catch_unwind`
|
= help: within `Gradient`, the trait `RefUnwindSafe` is not implemented for `(dyn colorous::gradient::EvalGradient + Send + Sync + 'static)`
= note: required because it appears within the type `&'static (dyn colorous::gradient::EvalGradient + Send + Sync + 'static)`
= note: required because it appears within the type `Gradient`
= note: required because of the requirements on the impl of `UnwindSafe` for `&Gradient`
= note: required because it appears within the type `[closure@src/main.rs:3:38: 3:62]`
```
Implement advance_by, advance_back_by for slice::{Iter, IterMut}
Part of #77404.
Picking up where #77633 was closed.
I have addressed https://github.com/rust-lang/rust/pull/77633#issuecomment-771842599 by restoring `nth` and `nth_back`. So according to that comment this should already be r=m-ou-se, but it has been sitting for a while.
Track caller of Vec::remove()
`vec.remove(invalid)` doesn't print a helpful source position:
> thread 'main' panicked at 'removal index (is 99) should be < len (is 1)', **library/alloc/src/vec/mod.rs:1379:13**
Add docs about performance and `Iterator::map` to `[T; N]::map`
This suboptimal code gen for some usages of array::map got a bit of
attention by multiple people throughout the community. Some cases:
- https://github.com/rust-lang/rust/issues/75243#issuecomment-866051086
- https://github.com/rust-lang/rust/issues/75243#issuecomment-874732134
- https://www.reddit.com/r/rust/comments/oeqqf7/unexpected_high_stack_usage/
My *guess* is that this gets the attention it gets because in JavaScript
(and potentially other languages), a `map` function on arrays is very
commonly used since in those languages, arrays basically take the role
of Rust's iterator. I considered explicitly naming JavaScript in the
first paragraph I added, but I couldn't find precedence of mentioning
other languages in standard library doc, so I didn't add it.
When array::map was stabilized, we still wanted to add docs, but that
somehow did not happen in time. So here we are. Not sure if this sounds
crazy but maybe it is worth considering beta backporting this? Only if
it's not a lot of work, of course! But yeah, stabilized array::map is
already in beta and if this problem is really as big as it sometimes seems,
might be worth having the docs in place when 1.55 is released.
CC ``@CryZe``
r? ``@m-ou-se`` (since you were involved in that discussion and the stabilization)
Make `SEMICOLON_IN_EXPRESSIONS_FROM_MACROS` warn by default
This PR makes the `SEMICOLON_IN_EXPRESSIONS_FROM_MACROS` lint warn by default.
To avoid showing a large number of un-actionable warnings to users, we only enable the lint for macros defined in the same crate. This ensures that users will be able to fix the warning by simply removing a semicolon.
In the future, I'd like to enable this lint unconditionally, and eventually make it into a hard error in a future edition. This PR is a step towards that goal.
[backtraces]: look for the `begin` symbol only after seeing `end`
On `x86_64-pc-windows-msvc`, we often get backtraces which look like
this:
```
10: 0x7ff77e0e9be5 - std::panicking::rust_panic_with_hook
11: 0x7ff77e0e11b4 - std::sys_common::backtrace::__rust_begin_short_backtrace::h5769736bdb11136c
12: 0x7ff77e0e116f - std::sys_common::backtrace::__rust_end_short_backtrace::h61c7ecb1b55338ae
13: 0x7ff77e0f89dd - std::panicking::begin_panic::h8e60ef9f82a41805
14: 0x7ff77e0e108c - d
15: 0x7ff77e0e1069 - c
16: 0x7ff77e0e1059 - b
17: 0x7ff77e0e1049 - a
18: 0x7ff77e0e1039 - core::ptr::drop_in_place<std::rt::lang_start<()>::{{closure}}>::h1bfcd14d5e15ba81
19: 0x7ff77e0e1186 - std::sys_common::backtrace::__rust_begin_short_backtrace::h5769736bdb11136c
20: 0x7ff77e0e100c - std::rt::lang_start::{{closure}}::ha054184bbf9921e3
```
Notice that `__rust_begin_short_backtrace` appears on frame 11 before
`__rust_end_short_backtrace` on frame 12. This is because in typical
release binaries without debug symbols, dbghelp.dll, which we use to walk
and symbolize the stack, does not know where CGU internal functions
start or end and so the closure invoked by `__rust_end_short_backtrace`
is incorrectly described as `__rust_begin_short_backtrace` because it
happens to be near that symbol.
While that can obviously change, this has been happening quite
consistently since #75048. Since this is a very small change to the std
and the change makes sense by itself, I think this is worth doing.
This doesn't completely resolve the situation for release binaries on
Windows, since without debug symbols, the stack printed can still show
incorrect symbol names (this is why the test uses `#[no_mangle]`) but it
does slightly improve the situation in that you see the same backtrace
you would see with `RUST_BACKTRACE=full` or in a debugger (without the
uninteresting bits at the top and bottom).
Fixes part of #87481
Update the examples in `String` and `VecDeque::retain`
The examples added in #60396 used a "clever" post-increment hack,
unrelated to the actual point of the examples. That hack was found
[confusing] in the users forum, and #81811 already changed the `Vec`
example to use a more direct iterator. This commit changes `String` and
`VecDeque` in the same way for consistency.
[confusing]: https://users.rust-lang.org/t/help-understand-strange-expression/62858
Optimize fmt::PadAdapter::wrap
After adding the first `write!` usage to my project and printing the result to the console, I noticed, that my binary contains the strings "called `Option::unwrap()` on a `None` value`" and more importantly "C:\Users\Patrick Fischer\.rustup\toolchains\nightly-x86_64-pc-windows-msvc\lib\rustlib\src\rust\library\core\src\fmt\builders.rs", with my release build being configured as follows:
```
[profile.release]
panic = "abort"
codegen-units = 1
strip = "symbols" # the important bit
lto = true
```
I am in a no_std environment and my custom panic handler is a simple `loop {}`. I did not expect the above information to be preserved. I heavily suspect the edited function to be the culprit. It contains the only direct use of `Option::unwrap` in the entire file and I tracked the symbols in the assembly to be used from the section `_ZN68_$LT$core..fmt..builders..PadAdapter$u20$as$u20$core..fmt..Write$GT$9write_str17ha1d5e5efe167202aE`.
Aside from me suspecting this function to be the culprit, the replaced code performs the same operation as `Option::insert`, but without the `unreachable_unchecked` optimization `Option::insert` provides. Therefore, it makes sense to me to use the more optimized version, instead.
As I don't change any semantics, I hope a simple pull request suffices.
Fix may not to appropriate might not or must not
I went through and changed occurrences of `may not` to be more explicit with `might not` and `must not`.
Since RFC 3052 soft deprecated the authors field anyway, hiding it from
crates.io, docs.rs, and making Cargo not add it by default, and it is
not generally up to date/useful information, we should remove it from
crates in this repo.
