$> gpg --version
gpg (GnuPG) 2.0.22
libgcrypt 1.5.3
...

$> spack --version
0.16.0-389-8919226

$> spack gpg trust e4s.pub
gpgconf: invalid option "--create-socketdir"
==> Error: None: No such file or directory: 'None'
Command: 'None' '--create-socketdir'

$> spack -d gpg trust e4s.pub
==> [2020-12-28-17:57:13.255469] Imported gpg from built-in commands
==> [2020-12-28-17:57:13.257931] Imported gpg from built-in commands
==> [2020-12-28-17:57:13.258679] '/usr/bin/gpgconf' '--version'
==> [2020-12-28-17:57:13.260456] '/usr/bin/gpgconf' '--dry-run' '--create-socketdir'
gpgconf: invalid option "--create-socketdir"
==> [2020-12-28-17:57:13.262194] '/usr/bin/gpg2' '--version'
==> [2020-12-28-17:57:13.264410] 'None' '--create-socketdir'
==> [2020-12-28-17:57:13.265610] ProcessError: None: No such file or directory: 'None'
    Command: 'None' '--create-socketdir'
==> [2020-12-28-17:57:13.265703] Error: None: No such file or directory: 'None'
Command: 'None' '--create-socketdir'
Traceback (most recent call last):
  File "/opt/spack/lib/spack/spack/util/executable.py", line 170, in __call__
    env=env)
  File "/usr/local/lib/python3.7/subprocess.py", line 775, in __init__
    restore_signals, start_new_session)
  File "/usr/local/lib/python3.7/subprocess.py", line 1522, in _execute_child
    raise child_exception_type(errno_num, err_msg, err_filename)
FileNotFoundError: [Errno 2] No such file or directory: 'None': 'None'

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/opt/spack/lib/spack/spack/main.py", line 762, in main
    return _invoke_command(command, parser, args, unknown)
  File "/opt/spack/lib/spack/spack/main.py", line 490, in _invoke_command
    return_val = command(parser, args)
  File "/opt/spack/lib/spack/spack/cmd/gpg.py", line 201, in gpg
    args.func(args)
  File "/opt/spack/lib/spack/spack/cmd/gpg.py", line 159, in gpg_trust
    spack.util.gpg.trust(args.keyfile)
  File "/opt/spack/lib/spack/spack/util/gpg.py", line 410, in trust
    return get_global_gpg_instance().trust(*args, **kwargs)
  File "/opt/spack/lib/spack/spack/util/gpg.py", line 345, in trust
    self('--import', keyfile)
  File "/opt/spack/lib/spack/spack/util/gpg.py", line 307, in __call__
    if self.prep:
  File "/opt/spack/lib/spack/llnl/util/lang.py", line 197, in _memoized_function
    func.cache[args] = func(*args)
  File "/opt/spack/lib/spack/spack/util/gpg.py", line 290, in prep
    self.gpgconf_exe('--create-socketdir')
  File "/opt/spack/lib/spack/spack/util/executable.py", line 204, in __call__
    '%s: %s' % (self.exe[0], e.strerror), 'Command: ' + cmd_line)
spack.util.executable.ProcessError: None: No such file or directory: 'None'
    Command: 'None' '--create-socketdir'