Path manipulation

Rolldown module / resolver paths are known UTF-8. Prefer rolldown_std_utils over open-coding sugar_path chains.

Implementation: crates/rolldown_std_utils/src/path_ext.rs. Module-id identity: module-id/implementation.md.

Use these

Helper	For
`absolutize_path_buf(path)`	Ensure an owned path is absolute
`relative_path_to_slash(target, base)`	Relative path as `/`-separated `String`
`relative_path_as_js_specifier(target, base)`	Same, JS form: `.` / `./…` / `../…`
`absolute_path_to_relative_slash(path, cwd)`	Absolute → cwd-relative slash string
`path_buf_to_slash(path)`	Owned `PathBuf` → slash `String`
`PathExt::expect_to_slash`	Borrowed path → slash `String`

sugar_path 3: relative returns Cow<Path> (empty when equal); normalize preserves a trailing separator; slash conversion is strict by default. Explicit cwd arguments must be absolute. Keep workspace feature cached_current_dir.

When the destination is ArcStr, pass to_slash() directly instead of calling into_owned() first; ArcStr copies strings into its own allocation.

Don't

rust

target.relative(base).to_slash_lossy().into_owned()  // lossy on known UTF-8
path.to_slash().unwrap()                             // 2.x API
target.relative(base).as_path().expect_to_slash()    // skip into_slash reuse
let p: PathBuf = target.relative(base);              // not PathBuf anymore
path.to_string_lossy().replace('\\', "/")            // hand-rolled policy

Module ids stay native separators; slash form is for output / stable strings only.