go_site_file leaves the ./ prefix on "./../x", contradicting its documented contract #138

• Repository: pingdotgg/ts-rust
• Target commit: 392e92eb06dc8bc136e0f309a0fb1fee04073254
• File: crates/ts_goport/src/gopanic.rs:496

Summary

go_site_file (crates/ts_goport/src/gopanic.rs:498-516) walks the path segments to shorten a panic site: it pops a parent segment only when the previous segment is not .. The documented contract says ./../x is ../x, but the guard treats the leading . as a normal directory, so nothing is popped and the unnormalized ./../x is returned. Panic/backtrace formatting uses this helper, so every site built from such a path keeps the spurious ./ prefix; the crate-root case (.../goport_core/../../src/core.rs) still normalizes because the preceding segment is a real name.

Affected code

crates/ts_goport/src/gopanic.rs:

  488      payload
  489  }
  490  
  491  /// The file of a port site (`Location::file`) as panic text prints it:
  492  /// without its `<dir>/..` pairs. The roots of the `parts/` crates are
  493  /// `../../src/<crate>_root.rs`, so their sites are
  494  /// `crates/ts_goport/parts/goport_core/../../src/...`. This gives
  495  /// `crates/ts_goport/src/...`, the text from before the crate split. A `.`
  496  /// segment does not pair with a `..` (`./../x` is `../x`, not `x`).
  497  #[must_use]
  498  pub fn go_site_file(file: &str) -> std::borrow::Cow<'_, str> {
  499      if !file.contains("..") {
  500          return std::borrow::Cow::Borrowed(file);
  501      }
  502      fn name(piece: &str) -> &str {
  503          piece.trim_end_matches(['/', '\\'])
  504      }
  505      // Each piece is a path segment with the separator after it.
  506      let mut pieces: Vec<&str> = Vec::new();
  507      for piece in file.split_inclusive(['/', '\\']) {
  508          let parent = pieces.last().map(|last| name(last));

Expected behavior

go_site_file normalizes a . segment before .. as documented, so ./../x becomes ../x.

Actual behavior

The doc comment at gopanic.rs:496 states ./../x is ../x, but the condition at line 509 only avoids popping the . parent and the concat at line 515 returns ./../x.

How to reproduce

Call go_site_file("./../x") from a small Rust test (compiling gopanic.rs via #[path]); the returned string is "./../x" instead of "../x".

Root cause

go_site_file (crates/ts_goport/src/gopanic.rs:498-516) walks the path segments to shorten a panic site: it pops a parent segment only when the previous segment is not .. The documented contract says ./../x is ../x, but the guard treats the leading . as a normal directory, so nothing is popped and the unnormalized ./../x is returned. Panic/backtrace formatting uses this helper, so every site built from such a path keeps the spurious ./ prefix; the crate-root case (.../goport_core/../../src/core.rs) still normalizes because the preceding segment is a real name.

Suggested fix

Normalize a leading ./ before the parent-pop loop:

if rest.starts_with("./") {
    rest = &rest[2..];
}

Keep the existing ../ normalization for crate-root paths, and add a table test covering ./../x, ./a/../b.ts and ../../src/core.rs.