rust/library
Yuki Okushi c1f9d985d7
Rollup merge of #102271 - lopopolo:lopopolo/stabilize-duration-try-from-secs-float, r=dtolnay
Stabilize `duration_checked_float`

## Stabilization Report

This stabilization report is for a stabilization of `duration_checked_float`, tracking issue: https://github.com/rust-lang/rust/issues/83400.

### Implementation History

- https://github.com/rust-lang/rust/pull/82179
- https://github.com/rust-lang/rust/pull/90247
- https://github.com/rust-lang/rust/pull/96051
- Changed error type to `FromFloatSecsError` in https://github.com/rust-lang/rust/pull/90247
- https://github.com/rust-lang/rust/pull/96051 changes the rounding mode to round-to-nearest instead of truncate.

## API Summary

This stabilization report proposes the following API to be stabilized in `core`, along with their re-exports in `std`:

```rust
// core::time

impl Duration {
    pub const fn try_from_secs_f32(secs: f32) -> Result<Duration, TryFromFloatSecsError>;
    pub const fn try_from_secs_f64(secs: f64) -> Result<Duration, TryFromFloatSecsError>;
}

#[derive(Debug, Clone, PartialEq, Eq)]
pub struct TryFromFloatSecsError { ... }

impl core::fmt::Display for TryFromFloatSecsError { ... }
impl core::error::Error for TryFromFloatSecsError { ... }
```

These functions are made const unstable under `duration_consts_float`, tracking issue #72440.

There is an open question in the tracking issue around what the error type should be called which I was hoping to resolve in the context of an FCP.

In this stabilization PR, I have altered the name of the error type to `TryFromFloatSecsError`. In my opinion, the error type shares the name of the method (adjusted to accommodate both types of floats), which is consistent with other error types in `core`, `alloc` and `std` like `TryReserveError` and `TryFromIntError`.

## Experience Report

Code such as this is ready to be converted to a checked API to ensure it is panic free:

```rust
impl Time {
    pub fn checked_add_f64(&self, seconds: f64) -> Result<Self, TimeError> {
        // Fail safely during `f64` conversion to duration
        if seconds.is_nan() || seconds.is_infinite() {
            return Err(TzOutOfRangeError::new().into());
        }

        if seconds.is_sign_positive() {
            self.checked_add(Duration::from_secs_f64(seconds))
        } else {
            self.checked_sub(Duration::from_secs_f64(-seconds))
        }
    }
}
```

See: https://github.com/artichoke/artichoke/issues/2194.

`@rustbot` label +T-libs-api -T-libs

cc `@mbartlett21`
2022-10-24 19:32:26 +09:00
..
alloc Rollup merge of #99578 - steffahn:remove_redundant_bound, r=thomcc 2022-10-24 19:32:24 +09:00
backtrace@07872f28cd Update backtrace 2022-09-02 16:09:58 -04:00
core Rollup merge of #102271 - lopopolo:lopopolo/stabilize-duration-try-from-secs-float, r=dtolnay 2022-10-24 19:32:26 +09:00
panic_abort Update comment about personalities in panic_abort 2022-08-23 16:12:58 +08:00
panic_unwind Auto merge of #92845 - Amanieu:std_personality, r=Mark-Simulacrum 2022-08-28 04:16:29 +00:00
portable-simd separate the receiver from arguments in HIR under /clippy 2022-09-05 22:25:57 +09:00
proc_macro Stabilize proc_macro::Span::source_text 2022-10-18 17:13:41 +02:00
profiler_builtins Fully stabilize NLL 2022-06-03 17:16:41 -04:00
rtstartup Remove custom frame info registration on i686-pc-windows-gnu 2022-08-23 16:12:58 +08:00
rustc-std-workspace-alloc Switch all libraries to the 2021 edition 2021-12-23 19:03:47 +08:00
rustc-std-workspace-core Switch all libraries to the 2021 edition 2021-12-23 19:03:47 +08:00
rustc-std-workspace-std Switch all libraries to the 2021 edition 2021-12-23 19:03:47 +08:00
std Rollup merge of #102271 - lopopolo:lopopolo/stabilize-duration-try-from-secs-float, r=dtolnay 2022-10-24 19:32:26 +09:00
stdarch@790411f93c library: update stdarch submodule 2022-10-13 09:41:16 +08:00
test Rollup merge of #99939 - saethlin:pre-sort-tests, r=thomcc,jackh726 2022-10-24 19:32:25 +09:00
unwind unwind: don't build dependency when building for Miri 2022-08-15 12:54:12 -04:00