Avoid redundant WTF-8 checks in `PathBuf`
Eliminate checks for WTF-8 boundaries in `PathBuf::set_extension` and `add_extension`, where joining WTF-8 surrogate halves is impossible. Don't convert the `str` to `OsStr`, because `OsString::push` specializes to skip the joining when given strings.
To assist in this, mark the internal methods `OsString::truncate` and `extend_from_slice` as `unsafe` to communicate their safety invariants better than with module privacy.
Similar to #137777.
cc `@joboet` `@ChrisDenton`
Stabilise `std::ffi::c_str`
This finished FCP in #112134 but never actually got a stabilisation PR. Since the FCP in #120048 recently passed to add the `os_str` module, it would be nice to also merge this too, to ensure that both get added in the next version.
Note: The added stability attributes which *somehow* were able to be omitted before (rustc bug?) were added based on the fact that they were added in 302551388b, which ended up in 1.85.0.
Closes: https://github.com/rust-lang/rust/issues/112134
r? libs-api
The WTF-8 version of `OsString` tracks whether it is known to be valid
UTF-8 with its `is_known_utf8` field. Specialize `From<AsRef<OsStr>>` so
this can be set for UTF-8 string types.
When concatenating two WTF-8 strings, surrogate pairs at the boundaries
need to be joined. However, since UTF-8 strings cannot contain surrogate
halves, this check can be skipped when one string is UTF-8. Specialize
`OsString::push` to use a more efficient concatenation in this case.
Unfortunately, a specialization for `T: AsRef<str>` conflicts with
`T: AsRef<OsStr>`, so stamp out string types with a macro.
Rustdoc has no way to show that an item is stable,
but only at a different path. `std::ffi::c_str::NulError` is
not stable, but `std::ffi::NulError` is.
To avoid marking these types as unstable when someone just
wants to follow a link from `CString`, inline them into their
stable paths.
Since the stabilization in #127679 has reached stage0, 1.82-beta, we can
start using `&raw` freely, and even the soft-deprecated `ptr::addr_of!`
and `ptr::addr_of_mut!` can stop allowing the unstable feature.
I intentionally did not change any documentation or tests, but the rest
of those macro uses are all now using `&raw const` or `&raw mut` in the
standard library.
Document overrides of `clone_from()` in core/std
As mentioned in https://github.com/rust-lang/rust/pull/96979#discussion_r1379502413
Specifically, when an override doesn't just forward to an inner type, document the behavior and that it's preferred over simply assigning a clone of source. Also, change instances where the second parameter is "other" to "source".
I reused some of the wording over and over for similar impls, but I'm not sure that the wording is actually *good*. Would appreciate feedback about that.
Also, now some of these seem to provide pretty specific guarantees about behavior (e.g. will reuse the exact same allocation iff the len is the same), but I was basing it off of the docs for [`Box::clone_from`](https://doc.rust-lang.org/1.75.0/std/boxed/struct.Box.html#method.clone_from-1) - I'm not sure if providing those strong guarantees is actually good or not.
Specifically, when an override doesn't just forward to an inner type,
document the behavior and that it's preferred over simply assigning
a clone of source. Also, change instances where the second parameter is
"other" to "source".
Help with common API confusion, like asking for `push` when the data structure really has `append`.
```
error[E0599]: no method named `size` found for struct `Vec<{integer}>` in the current scope
--> $DIR/rustc_confusables_std_cases.rs:17:7
|
LL | x.size();
| ^^^^
|
help: you might have meant to use `len`
|
LL | x.len();
| ~~~
help: there is a method with a similar name
|
LL | x.resize();
| ~~~~~~
```
#59450
On Windows and UEFI this improves performance and error messaging.
On other platforms we optimize the fast path a bit more.
This also prepares for later relaxing the checks on certain platforms.
Add `display` method to `OsStr` for lossy display of an `OsStr` which may contain invalid unicode.
Invalid Unicode sequences are replaced with `U+FFFD REPLACEMENT CHARACTER`.
This change also makes the `std::ffi::os_str` module public.
detects redundant imports that can be eliminated.
for #117772 :
In order to facilitate review and modification, split the checking code and
removing redundant imports code into two PR.
