https://github.com/rust-lang/rfcs/pull/221
The current terminology of "task failure" often causes problems when
writing or speaking about code. You often want to talk about the
possibility of an operation that returns a Result "failing", but cannot
because of the ambiguity with task failure. Instead, you have to speak
of "the failing case" or "when the operation does not succeed" or other
circumlocutions.
Likewise, we use a "Failure" header in rustdoc to describe when
operations may fail the task, but it would often be helpful to separate
out a section describing the "Err-producing" case.
We have been steadily moving away from task failure and toward Result as
an error-handling mechanism, so we should optimize our terminology
accordingly: Result-producing functions should be easy to describe.
To update your code, rename any call to `fail!` to `panic!` instead.
Assuming you have not created your own macro named `panic!`, this
will work on UNIX based systems:
grep -lZR 'fail!' . | xargs -0 -l sed -i -e 's/fail!/panic!/g'
You can of course also do this by hand.
[breaking-change]
Closes#16097 (fix variable name in tutorial)
Closes#16100 (More defailbloating)
Closes#16104 (Fix deprecation commment on `core::cmp::lexical_ordering`)
Closes#16105 (fix formatting in pointer guide table)
Closes#16107 (remove serialize::ebml, add librbml)
Closes#16108 (Fix heading levels in pointer guide)
Closes#16109 (rustrt: Don't conditionally init the at_exit QUEUE)
Closes#16111 (hexfloat: Deprecate to move out of the repo)
Closes#16113 (Add examples for GenericPath methods.)
Closes#16115 (Byte literals!)
Closes#16116 (Add a non-regression test for issue #8372)
Closes#16120 (Deprecate semver)
Closes#16124 (Deprecate uuid)
Closes#16126 (Deprecate fourcc)
Closes#16127 (Remove incorrect example)
Closes#16129 (Add note about production deployments.)
Closes#16131 (librustc: Don't ICE when trying to subst regions in destructor call.)
Closes#16133 (librustc: Don't ICE with struct exprs where the name is not a valid struct.)
Closes#16136 (Implement slice::Vector for Option<T> and CVec<T>)
Closes#16137 (alloc, arena, test, url, uuid: Elide lifetimes.)
This commit changes the `io::process::Command` API to provide
fine-grained control over the environment:
* The `env` method now inserts/updates a key/value pair.
* The `env_remove` method removes a key from the environment.
* The old `env` method, which sets the entire environment in one shot,
is renamed to `env_set_all`. It can be used in conjunction with the
finer-grained methods. This renaming is a breaking change.
To support these new methods, the internal `env` representation for
`Command` has been changed to an optional `HashMap` holding owned
`CString`s (to support non-utf8 data). The `HashMap` is only
materialized if the environment is updated. The implementation does not
try hard to avoid allocation, since the cost of launching a process will
dwarf any allocation cost.
This patch also adds `PartialOrd`, `Eq`, and `Hash` implementations for
`CString`.
[breaking-change]
This change registers new snapshots, allowing `*T` to be removed from the language. This is a large breaking change, and it is recommended that if compiler errors are seen that any FFI calls are audited to determine whether they should be actually taking `*mut T`.
This breaks a fair amount of code. The typical patterns are:
* `for _ in range(0, 10)`: change to `for _ in range(0u, 10)`;
* `println!("{}", 3)`: change to `println!("{}", 3i)`;
* `[1, 2, 3].len()`: change to `[1i, 2, 3].len()`.
RFC #30. Closes#6023.
[breaking-change]
There's a fair number of attributes that have to be whitelisted since
they're either looked for by rustdoc, in trans, or as needed. These can
be cleaned up in the future.
The existing APIs for spawning processes took strings for the command
and arguments, but the underlying system may not impose utf8 encoding,
so this is overly limiting.
The assumption we actually want to make is just that the command and
arguments are viewable as [u8] slices with no interior NULLs, i.e., as
CStrings. The ToCStr trait is a handy bound for types that meet this
requirement (such as &str and Path).
However, since the commands and arguments are often a mixture of
strings and paths, it would be inconvenient to take a slice with a
single T: ToCStr bound. So this patch revamps the process creation API
to instead use a builder-style interface, called `Command`, allowing
arguments to be added one at a time with differing ToCStr
implementations for each.
The initial cut of the builder API has some drawbacks that can be
addressed once issue #13851 (libstd as a facade) is closed. These are
detailed as FIXMEs.
Closes#11650.
[breaking-change]
This implements set_timeout() for std::io::Process which will affect wait()
operations on the process. This follows the same pattern as the rest of the
timeouts emerging in std::io::net.
The implementation was super easy for everything except libnative on unix
(backwards from usual!), which required a good bit of signal handling. There's a
doc comment explaining the strategy in libnative. Internally, this also required
refactoring the "helper thread" implementation used by libnative to allow for an
extra helper thread (not just the timer).
This is a breaking change in terms of the io::Process API. It is now possible
for wait() to fail, and subsequently wait_with_output(). These two functions now
return IoResult<T> due to the fact that they can time out.
Additionally, the wait_with_output() function has moved from taking `&mut self`
to taking `self`. If a timeout occurs while waiting with output, the semantics
are undesirable in almost all cases if attempting to re-wait on the process.
Equivalent functionality can still be achieved by dealing with the output
handles manually.
[breaking-change]
cc #13523
This commit switches over the backtrace infrastructure from piggy-backing off
the RUST_LOG environment variable to using the RUST_BACKTRACE environment
variable (logging is now disabled in libstd).
Whenever a failure happens, if a program is run with
`RUST_LOG=std::rt::backtrace` a backtrace will be printed to the task's stderr
handle. Stack traces are uncondtionally printed on double-failure and
rtabort!().
This ended up having a nontrivial implementation, and here's some highlights of
it:
* We're bundling libbacktrace for everything but OSX and Windows
* We use libgcc_s and its libunwind apis to get a backtrace of instruction
pointers
* On OSX we use dladdr() to go from an instruction pointer to a symbol
* On unix that isn't OSX, we use libbacktrace to get symbols
* Windows, as usual, has an entirely separate implementation
Lots more fun details and comments can be found in the source itself.
Closes#10128
