"""
issue 11588 proposed test case:

output_group = parser.add_mutually_exclusive_group(required=True)
output_group.add_argument("-o", "--outfile")
outdir_group = output_group.add_necessarily_inclusive_group()
outdir_group.add_argument("-O", "--outdir")
outfile_group = outdir_group.add_mutually_exclusive_group(required=True)
outfile_group.add_argument("-p", "--outpattern")
outfile_group.add_argument("-s", "--outsuffix")

The usage should then look like:

(-o FILE | (-O DIR & (-p PATTERN | -s SUFFIX))
"""
"""
Implementation using parser.register('cross_tests',...)
and hand crafted test functions
"""

import argparse
usage = '(-o FILE | (-O DIR & (-p PATTERN | -s SUFFIX))'
parser = argparse.ArgumentParser(usage=usage)
a_file= parser.add_argument("-o", "--outfile", metavar='FILE')
a_dir = parser.add_argument("-O", "--outdir", metavar='DIR')
a_pat = parser.add_argument("-p", "--outpattern", metavar='PATTERN')
a_suf = parser.add_argument("-s", "--outsuffix", metavar='SUFFIX')

# hand crafted tests
def pat_or_suf(parser, seen_actions, *args):
    if 2==len(seen_actions.intersection([a_pat, a_suf])):
        parser.error('only one of PATTERN and SUFFIX allowed')
parser.register('cross_tests', 'pat_or_suf', pat_or_suf)

def dir_inclusive(parser, seen_actions, *args):
    if a_dir in seen_actions:
        if 0==len(seen_actions.intersection([a_pat, a_suf])):
            parser.error('DIR requires PATTERN or SUFFIX')
parser.register('cross_tests', 'dir_inclusive', dir_inclusive)

def file_or_dir(parser, seen_actions, *args):
    if a_file in seen_actions:
        cnt = len(seen_actions.intersection([a_dir, a_pat, a_suf]))
        if cnt>0:
            parser.error('FILE cannot have DIR, PATTERN or SUFFIX')
    elif a_dir not in seen_actions:
            parser.error('require FILE or DIR')
parser.register('cross_tests', 'file_or_dir', file_or_dir)

parser.parse_args()