message: qa: Prevent concurrency issues reading .cookie file
diff: @@ -323,12 +323,14 @@ def get_auth_cookie(datadir):
  if line.startswith("rpcpassword="):
  assert password is None # Ensure that there is only one rpcpassword line
  password = line.split("=")[1].strip("\n")
  - if os.path.isfile(os.path.join(datadir, "regtest", ".cookie")) and os.access(os.path.join(datadir, "regtest", ".cookie"), os.R_OK):
  + try:
  with open(os.path.join(datadir, "regtest", ".cookie"), 'r', encoding="ascii") as f:
  userpass = f.read()
  split_userpass = userpass.split(':')
  user = split_userpass[0]
  password = split_userpass[1]
  + except OSError:
  + pass
  if user is None or password is None:
  raise ValueError("No RPC credentials")
  return user, password
  