Document "standard" conventions for error messages
These are currently documented in the API guidelines:
https://rust-lang.github.io/api-guidelines/interoperability.html#error-types-are-meaningful-and-well-behaved-c-good-err
I think it makes sense to uplift this guideline (in a milder form) into
std docs. Printing and producing errors is something that even
non-expert users do frequently, so it is useful to give at least some
indication of what a typical error message looks like.
Fix stack overflow detection on FreeBSD 11.1+
Beginning with FreeBSD 10.4 and 11.1, there is one guard page by
default. And the stack autoresizes, so if Rust allocates its own guard
page, then FreeBSD's will simply move up one page. The best solution is
to just use the OS's guard page.
Rework `std::sys::windows::alloc`
I came across https://github.com/rust-lang/rust/pull/76676#discussion_r488729990, which points out that there was unsound code in the Windows alloc code, creating a &mut to possibly uninitialized memory. I reworked the code so that that particular issue does not occur anymore, and started adding more documentation and safety comments.
Full list of changes:
- moved and documented the relevant Windows Heap API functions
- refactor `allocate_with_flags` to `allocate` (and remove the other helper functions), which now takes just a `bool` if the memory should be zeroed
- add checks for if `GetProcessHeap` returned null
- add a test that checks if the size and alignment of a `Header` are indeed <= `MIN_ALIGN`
- add `#![deny(unsafe_op_in_unsafe_fn)]` and the necessary unsafe blocks with safety comments
I feel like I may have overdone the documenting, the unsoundness fix is the most important part; I could spit this PR up in separate parts.
Fix comment typo in once.rs
I believe I came across a minor typo in a comment. I am not particularly familiar with this part of the codebase, but I have read the surrounding code as well as the referenced `park` and `unpark` functions, and I believe my proposed change is true to the intended meaning of the comment.
I intentionally tried to keep the change as minimal as possible. If I have the maintainers' permission, I'd also love to add a comma to improve readability as follows: `Luckily ``park`` comes with the guarantee that if it got an ``unpark`` just before on an unparked thread, it does not park.`
Rename `#[doc(spotlight)]` to `#[doc(notable_trait)]`
Fixes#80936.
"spotlight" is not a very specific or self-explaining name.
Additionally, the dialog that it triggers is called "Notable traits".
So, "notable trait" is a better name.
* Rename `#[doc(spotlight)]` to `#[doc(notable_trait)]`
* Rename `#![feature(doc_spotlight)]` to `#![feature(doc_notable_trait)]`
* Update documentation
* Improve documentation
r? `@Manishearth`
Beginning with FreeBSD 10.4 and 11.1, there is one guard page by
default. And the stack autoresizes, so if Rust allocates its own guard
page, then FreeBSD's will simply move up one page. The best solution is
to just use the OS's guard page.
Disallow octal format in Ipv4 string
In its original specification, leading zero in Ipv4 string is interpreted
as octal literals. So a IP address 0127.0.0.1 actually means 87.0.0.1.
This confusion can lead to many security vulnerabilities. Therefore, in
[IETF RFC 6943], it suggests to disallow octal/hexadecimal format in Ipv4
string all together.
Existing implementation already disallows hexadecimal numbers. This commit
makes Parser reject octal numbers.
Fixes#83648.
[IETF RFC 6943]: https://tools.ietf.org/html/rfc6943#section-3.1.1
In its original specification, leading zero in Ipv4 string is interpreted
as octal literals. So a IP address 0127.0.0.1 actually means 87.0.0.1.
This confusion can lead to many security vulnerabilities. Therefore, in
[IETF RFC 6943], it suggests to disallow octal/hexadecimal format in Ipv4
string all together.
Existing implementation already disallows hexadecimal numbers. This commit
makes Parser reject octal numbers.
Fixes#83648.
[IETF RFC 6943]: https://tools.ietf.org/html/rfc6943#section-3.1.1
unix: Fix feature(unix_socket_ancillary_data) on macos and other BSDs
This adds support for CMSG handling on macOS and fixes it on OpenBSD and possibly other BSDs.
When traversing the CMSG list, the previous code had an exception for Android where the next element after the last pointer could point to the first pointer instead of NULL. This is actually not specific to Android: the `libc::CMSG_NXTHDR` implementation for Linux and emscripten have a special case to return NULL when the length of the previous element is zero; most other implementations simply return the previous element plus a zero offset in this case.
This MR makes the check non-optional which fixes CMSG handling and a possible endless loop on such systems; tested with file descriptor passing on OpenBSD, Linux, and macOS.
This MR additionally adds `SocketAncillary::is_empty` because clippy is right that it should be added.
This belongs to the `feature(unix_socket_ancillary_data)` tracking issue: https://github.com/rust-lang/rust/issues/76915
r? `@joshtriplett`
Improve fs error open_from unix
Consistency for #79399
Suggested by JohnTitor
r? `@JohnTitor`
Not user if the error is too long now, do we handle long errors well?
Add function core::iter::zip
This makes it a little easier to `zip` iterators:
```rust
for (x, y) in zip(xs, ys) {}
// vs.
for (x, y) in xs.into_iter().zip(ys) {}
```
You can `zip(&mut xs, &ys)` for the conventional `iter_mut()` and
`iter()`, respectively. This can also support arbitrary nesting, where
it's easier to see the item layout than with arbitrary `zip` chains:
```rust
for ((x, y), z) in zip(zip(xs, ys), zs) {}
for (x, (y, z)) in zip(xs, zip(ys, zs)) {}
// vs.
for ((x, y), z) in xs.into_iter().zip(ys).zip(xz) {}
for (x, (y, z)) in xs.into_iter().zip((ys.into_iter().zip(xz)) {}
```
It may also format more nicely, especially when the first iterator is a
longer chain of methods -- for example:
```rust
iter::zip(
trait_ref.substs.types().skip(1),
impl_trait_ref.substs.types().skip(1),
)
// vs.
trait_ref
.substs
.types()
.skip(1)
.zip(impl_trait_ref.substs.types().skip(1))
```
This replaces the tuple-pair `IntoIterator` in #78204.
There is prior art for the utility of this in [`itertools::zip`].
[`itertools::zip`]: https://docs.rs/itertools/0.10.0/itertools/fn.zip.html
Improve Debug implementations of Mutex and RwLock.
This improves the Debug implementations of Mutex and RwLock.
They now show the poison flag and use debug_non_exhaustive. (See #67364.)
Derive Debug for io::Chain instead of manually implementing it.
This derives Debug for io::Chain instead of manually implementing it.
The manual implementation has the same bounds, so I don't think there's any reason for a manual implementation. The names used in the derive implementation are even nicer (`first`/`second`) than the manual implementation (`t`/`u`), and include the `done_first` field too.
Fix Debug implementation for RwLock{Read,Write}Guard.
This would attempt to print the Debug representation of the lock that the guard has locked, which will try to lock again, fail, and just print `"<locked>"` unhelpfully.
After this change, this just prints the contents of the mutex, like the other smart pointers (and MutexGuard) do.
MutexGuard had this problem too: https://github.com/rust-lang/rust/issues/57702
ExitStatus: print "exit status: {}" rather than "exit code: {}" on unix
Proper Unix terminology is "exit status" (vs "wait status"). "exit
code" is imprecise on Unix and therefore unclear. (As far as I can
tell, "exit code" is correct terminology on Windows.)
This new wording is unfortunately inconsistent with the identifier
names in the Rust stdlib.
It is the identifier names that are wrong, as discussed at length in eg
https://doc.rust-lang.org/nightly/std/process/struct.ExitStatus.htmlhttps://doc.rust-lang.org/nightly/std/os/unix/process/trait.ExitStatusExt.html
Unfortunately for API stability reasons it would be a lot of work, and
a lot of disruption, to change the names in the stdlib (eg to rename
`std::process::ExitStatus` to `std::process::ChildStatus` or
something), but we should fix the message output. Many (probably
most) readers of these messages about exit statuses will be users and
system administrators, not programmers, who won't even know that Rust
has this wrong terminology.
So I think the right thing is to fix the documentation (as I have
already done) and, now, the terminology in the implementation.
This is a user-visible change to the behaviour of all Rust programs
which run Unix subprocesses. Hopefully no-one is matching against the
exit status string, except perhaps in tests.
The manual implementation has the same bounds, so I don't think there's
any reason for a manual implementation. The names used in the derive
implementation are even nicer (`first`/`second`) than the manual
implementation (`t`/`u`), and include the `done_first` field too.
This would attempt to print the Debug representation of the lock that
the guard has locked, which will try to lock again, fail, and just print
"<locked>" unhelpfully.
After this change, this just prints the contents of the mutex, like the
other smart pointers (and MutexGuard) do.
Add IEEE 754 compliant fmt/parse of -0, infinity, NaN
This pull request improves the Rust float formatting/parsing libraries to comply with IEEE 754's formatting expectations around certain special values, namely signed zero, the infinities, and NaN. It also adds IEEE 754 compliance tests that, while less stringent in certain places than many of the existing flt2dec/dec2flt capability tests, are intended to serve as the beginning of a roadmap to future compliance with the standard. Some relevant documentation is also adjusted with clarifying remarks.
This PR follows from discussion in https://github.com/rust-lang/rfcs/issues/1074, and closes#24623.
The most controversial change here is likely to be that -0 is now printed as -0. Allow me to explain: While there appears to be community support for an opt-in toggle of printing floats as if they exist in the naively expected domain of numbers, i.e. not the extended reals (where floats live), IEEE 754-2019 is clear that a float converted to a string should be capable of being transformed into the original floating point bit-pattern when it satisfies certain conditions (namely, when it is an actual numeric value i.e. not a NaN and the original and destination float width are the same). -0 is given special attention here as a value that should have its sign preserved. In addition, the vast majority of other programming languages not only output `-0` but output `-0.0` here.
While IEEE 754 offers a broad leeway in how to handle producing what it calls a "decimal character sequence", it is clear that the operations a language provides should be capable of round tripping, and it is confusing to advertise the f32 and f64 types as binary32 and binary64 yet have the most basic way of producing a string and then reading it back into a floating point number be non-conformant with the standard. Further, existing documentation suggested that e.g. -0 would be printed with -0 regardless of the presence of the `+` fmt character, but it prints "+0" instead if given such (which was what led to the opening of #24623).
There are other parsing and formatting issues for floating point numbers which prevent Rust from complying with the standard, as well as other well-documented challenges on the arithmetic level, but I hope that this can be the beginning of motion towards solving those challenges.
