// tests/helpers/child-env.mjs
// The environment a test gives a child process. The lock CLI
// (lib/util/test-lock.mjs) writes a session pointer keyed by
// CLAUDE_CODE_SESSION_ID; a child that inherits the id of the session running
// the tests writes a pointer for that live session (S133). So the id never
// reaches a child unless the test sets one itself. Same shape as
// lib/util/command-env.mjs. tests/lib/session-id-isolation.test.mjs checks that
// no other file under tests/ hands the process environment to a child.

/**
 * A copy of process.env without CLAUDE_CODE_SESSION_ID, with `overrides`
 * applied last (a test that sets its own id keeps it).
 *
 * @param {Record<string, string|undefined>} [overrides] - vars to set or replace
 * @returns {Record<string, string|undefined>} the child's environment
 */
export function childEnv(overrides = {}) {
  const { CLAUDE_CODE_SESSION_ID, ...rest } = process.env;
  return { ...rest, ...overrides };
}