Tracking Issue for `os_str_split_at`

Feature gate: #![feature(os_str_split_at)]

This is a tracking issue for OsStr::{split_at, split_at_checked}.

This allows splitting OsStr on a valid UTF-8 boundary cross-platform.

Public API

// std::ffi
impl OsStr {
    // Panic if `mid` is not a valid boundary
    pub const fn split_at(&self, mid: usize) -> (&OsStr, &OsStr);
    // Returns `None` if `mid` is not a valid boundary
    pub const fn split_at_checked(&self, mid: usize) -> Option<(&OsStr, &OsStr)>;
}

Steps / History

(Remember to update the S-tracking-* label when checking boxes.)

• ACP: rust-lang/libs-team#780
• Implementation: #...
• Final comment period (FCP)^1
• Stabilization PR

Unresolved Questions

• On platforms where OsStr is just bytes (e.g. Unix), should it allow splitting at arbitrary indexes? However, this would mean that you could safely write non-portable code using OsStr.

Start with the std::ffi::OsStr API and the proposed split_at and split_at_checked signatures under the os_str_split_at feature gate. Review the unresolved question about arbitrary byte-index splitting on Unix before determining the implementation scope. Done means the implementation is complete, the portability question is resolved, and the tracking checklist is updated.