pty-env.js

// Environment for PTY children.
//
// Two jobs:
//
// 1. Strip Electron internals that cause nested Electron apps (or node-pty
//    inside them) to malfunction.
//
// 2. Guarantee a UTF-8 character encoding. An app launched from Finder or the
//    Dock on macOS inherits no shell environment, so LANG/LC_* are simply
//    absent — launchd does not set them. Locale-sensitive tools then fall back
//    to the "standard C encoding", which on macOS means Mac OS Roman. `pbcopy`
//    is the one users notice: it reads UTF-8 bytes as Mac OS Roman, so an
//    agent response copied out of a session arrives on the clipboard as
//    "‚Ķ‚Äî‚Üí" instead of "…—→" (issue #89).
//
//    LC_CTYPE alone is deliberate. It fixes character handling and nothing
//    else — collation, dates, and number formatting stay on the system
//    default rather than being forced to some guessed region.

const LOCALE_VARS = ['LC_ALL', 'LC_CTYPE', 'LANG'];

function buildPtyEnv(sourceEnv) {
  const env = Object.fromEntries(
    Object.entries(sourceEnv).filter(([k]) =>
      !k.startsWith('ELECTRON_') &&
      !k.startsWith('GOOGLE_API_KEY') &&
      k !== 'NODE_OPTIONS' &&
      k !== 'ORIGINAL_XDG_CURRENT_DESKTOP' &&
      k !== 'WT_SESSION'
    )
  );

  // Only when the parent handed us nothing usable — an inherited locale is the
  // user's own setting and must win. An empty value counts as absent, which is
  // what a GUI launch actually produces.
  if (!LOCALE_VARS.some((k) => env[k])) env.LC_CTYPE = 'UTF-8';

  return env;
}

module.exports = { buildPtyEnv };