Stabilize `std::io::ErrorKind::CrossesDevices`
FCP in #130191
cc #86442
See #130191 for more info and a recap of what has happened up until now.
TLDR: This had been FCP'd in December 2022 with some other `ErrorKind`s, but the stabilization got postponed due to some concerns voiced about several of the variants. However, the only concern ever voiced for this variant in particular was a wish to rename this to `NotSameDevice` analogous to Windows's `ERROR_NOT_SAME_DEVICE` (as opposed to Unix's `EXDEV`). This suggestion did not receive any support. So let's try to FCP this as is.
r? libs-api
Stabilize most of `io_error_more`
Sadly, venting my frustration with t-libs-api is not a constructive way to solve problems and get things done, so I will try to stick to stuff that actually matters here.
- Tracking issue for this feature was opened 3 years ago: #86442
- FCP to stabilize it was completed 19(!!) months ago: https://github.com/rust-lang/rust/issues/86442#issuecomment-1368082102
- A PR with stabilization was similarly open for 19 months: #106375, but nothing ever came out of it. Presumably (it is hard to judge given the lack of communication) because a few of the variants still had some concerns voiced about them, even after the FCP.
So, to highlight a common sentiment:
> Maybe uncontroversial variants can be stabilised first and other variants (such as `QuotaExceeded` or `FilesystemLoop`) later? [^1]
[^1]: https://github.com/rust-lang/rust/issues/106375#issuecomment-1435762236
> I would like to voice support stabilization of the uncontroversial variants. This would get those variants to stable and focus the discussion around the more controversial ones. I don't see any particular reason that all of these must be stabilized at the same time. [...] [^2]
[^2]: https://github.com/rust-lang/rust/pull/106375#issuecomment-1742661555
> Maybe some less-controversial subset could be stabilized sooner? What’s blocking this issue from making progress? [^3]
[^3]: https://github.com/rust-lang/rust/issues/86442#issuecomment-1691187483 (got 30 upvotes btw) (and no response)
So this is exactly what this PR does. It stabilizes the non-controversial variants now, leaving just a few of them behind.
Namely, this PR stabilizes:
- `HostUnreachable`
- `NetworkUnreachable`
- `NetworkDown`
- `NotADirectory`
- `IsADirectory`
- `DirectoryNotEmpty`
- `ReadOnlyFilesystem`
- `StaleNetworkFileHandle`
- `StorageFull`
- `NotSeekable`
- `FileTooLarge`
- `ResourceBusy`
- `ExecutableFileBusy`
- `Deadlock`
- `TooManyLinks`
- `ArgumentListTooLong`
- `Unsupported`
This PR does not stabilize:
- `FilesystemLoop`
- `FilesystemQuotaExceeded`
- `CrossesDevices`
- `InvalidFilename`
Hopefully, this will allow us to move forward with this highly and long awaited addition to std, both allowing to still polish the less clear parts of it and not leading to stagnation.
r? joshtriplett
because they seem to be listed as a part of t-libs-api and were one of the most responsive persons previously
Clarify `Error::last_os_error` can be weird
Fundamentally, querying the OS for error codes is a process that is deeply subject to the whims of chance and fortune. We can account for OS, but not for every combination of platform APIs. A compiled binary may not recognize new errors introduced years later. We should clarify a few especially odd situations, and what they mean: We can effectively promise nothing... if you ask for Rust to decode errors where none have occurred.
This allows removing mention of ErrorKind::Uncategorized.
That error variant is hidden deliberately, so we should not explicitly mention it.
This fixes#106937.
Since you had an opinion also: Does this solution seem acceptable?
r? ``@ChrisDenton``
Fundamentally, querying the OS for error codes is a process
that is deeply subject to the whims of chance and fortune.
We can account for OS, but not for every combination of platform APIs.
A compiled binary may not recognize new errors introduced years later.
We should clarify a few especially odd situations, and what they mean:
We can effectively promise nothing.
This allows removing mention of ErrorKind::Uncategorized.
That error variant is hidden quite deliberately, so we
should not explicitly mention it.
Add standard C error function aliases to last_os_error
This aids the discoverability of `io::Error::last_os_error()` by linking to commonly used error number functions from C/C++.
I've seen a few people not realize this exists, so hopefully this helps draw attention to the API to encourage using it over integer error codes.
