This commit is an implementation of [RFC 503][rfc] which is a stabilization
story for the prelude. Most of the RFC was directly applied, removing reexports.
Some reexports are kept around, however:
* `range` remains until range syntax has landed to reduce churn.
* `Path` and `GenericPath` remain until path reform lands. This is done to
prevent many imports of `GenericPath` which will soon be removed.
* All `io` traits remain until I/O reform lands so imports can be rewritten all
at once to `std::io::prelude::*`.
This is a breaking change because many prelude reexports have been removed, and
the RFC can be consulted for the exact list of removed reexports, as well as to
find the locations of where to import them.
[rfc]: https://github.com/rust-lang/rfcs/blob/master/text/0503-prelude-stabilization.md
[breaking-change]
Closes#20068
Hello! This is my first Rust patch, and I fear that I've probably skipped at least 7 critical steps. I'd appreciate your feedback and advice about how to contribute to Rust.
This patch is based on a discussion with @BurntSushi in #14602 a while back. I'm happy to revise it as needed to fit into the modern world. :-)
As discussed in that issue, the existing `at` and `name` functions represent two different results with the empty string:
1. Matched the empty string.
2. Did not match anything.
Consider the following example. This regex has two named matched groups, `key` and `value`. `value` is optional:
```rust
// Matches "foo", "foo;v=bar" and "foo;v=".
regex!(r"(?P<key>[a-z]+)(;v=(?P<value>[a-z]*))?");
```
We can access `value` using `caps.name("value")`, but there's no way for us to distinguish between the `"foo"` and `"foo;v="` cases.
Early this year, @BurntSushi recommended modifying the existing `at` and `name` functions to return `Option`, instead of adding new functions to the API.
This is a [breaking-change], but the fix is easy:
- `refs.at(1)` becomes `refs.at(1).unwrap_or("")`.
- `refs.name(name)` becomes `refs.name(name).unwrap_or("")`.
Closes#14602. As discussed in that issue, the existing `at` and `name`
functions represent two different results with the empty string:
1. Matched the empty string.
2. Did not match anything.
Consider the following example. This regex has two named matched
groups, `key` and `value`. `value` is optional:
```rust
// Matches "foo", "foo;v=bar" and "foo;v=".
regex!(r"(?P<key>[a-z]+)(;v=(?P<value>[a-z]*))?");
```
We can access `value` using `caps.name("value")`, but there's no way for
us to distinguish between the `"foo"` and `"foo;v="` cases.
Early this year, @BurntSushi recommended modifying the existing `at` and
`name` functions to return `Option`, instead of adding new functions to
the API.
This is a [breaking-change], but the fix is easy:
- `refs.at(1)` becomes `refs.at(1).unwrap_or("")`.
- `refs.name(name)` becomes `refs.name(name).unwrap_or("")`.
The test harness will make sure that the panic message contains the
specified string. This is useful to help make `#[should_fail]` tests a
bit less brittle by decreasing the chance that the test isn't
"accidentally" passing due to a panic occurring earlier than expected.
The behavior is in some ways similar to JUnit's `expected` feature:
`@Test(expected=NullPointerException.class)`.
Without the message assertion, this test would pass even though it's not
actually reaching the intended part of the code:
```rust
#[test]
#[should_fail(message = "out of bounds")]
fn test_oob_array_access() {
let idx: uint = from_str("13o").unwrap(); // oops, this will panic
[1i32, 2, 3][idx];
}
```
This breaks code that referred to variant names in the same namespace as
their enum. Reexport the variants in the old location or alter code to
refer to the new locations:
```
pub enum Foo {
A,
B
}
fn main() {
let a = A;
}
```
=>
```
pub use self::Foo::{A, B};
pub enum Foo {
A,
B
}
fn main() {
let a = A;
}
```
or
```
pub enum Foo {
A,
B
}
fn main() {
let a = Foo::A;
}
```
[breaking-change]
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]
This obsoletes the old `to_err_msg` method. Replace
println!("Error: {}", failure.to_err_msg())
let string = failure.to_err_msg();
with
println!("Error: {}", failure)
let string = failure.to_str();
[breaking-change]
There's no need to include this specific flag just for android. We can
already deal with what it tries to solve by using -C linker=/path/to/cc
and -C ar=/path/to/ar. The Makefiles for rustc already set this up when
we're crosscompiling.
I did add the flag to compiletest though so it can find gdb. Though, I'm
pretty sure we don't run debuginfo tests on android anyways right now.
[breaking-change]
* Added `// no-pretty-expanded` to pretty-print a test, but not run it through
the `expanded` variant.
* Removed #[deriving] and other expanded attributes after they are expanded
* Removed hacks around &str and &&str and friends (from both the parser and the
pretty printer).
* Un-ignored a bunch of tests
A new flag to the test runner, --nocapture, can be passed to instruct that the
output of tests should not be captured by default. The behavior can also be
triggered via a RUST_TEST_NOCAPTURE environment variable being set.
Closes#13374
