The nix 0.30.1 → 0.31.1 bump introduced a type mismatch in readline.rs due to rustyline v17.0.2 depending on nix 0.30.1 while RustPython uses 0.31.1 directly.

Changes

• Use rustyline from git (commit 7bbd279) which includes nix 0.31.1 support
  • Temporary until rustyline publishes a new release
  • Commit verified to contain nix 0.31 upgrade (Jan 23, 2026)
  • Added TODO comment for future maintainers

Type Conflict

// readline.rs line 149 - rustyline returns nix::errno::Errno from 0.30.1
Err(ReadlineError::Errno(num)) => ReadlineResult::OsError(num),
                                   // ^^^^^^^^^ expected nix 0.31.1, found 0.30.1

Git dependency resolves this by aligning both to nix 0.31.1.

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