If you have an optional nargs=argparse.REMAINDER argument defined
then, if specified, its value should contain all the remaining command-line content. However, it seems that value does not include later '--' arguments.

For example, the following works as expected:

import argparse
parser = argparse.ArgumentParser(prog="PROG")
parser.add_argument("--args", nargs=argparse.REMAINDER)
args = parser.parse_args("--args cmd --arg1 XX ZZ".split())
assert args.args == ["cmd", "--arg1", "XX", "ZZ"]

But the following fails with
'PROG: error: unrecognized arguments: -- ZZ':

import argparse
parser = argparse.ArgumentParser(prog="PROG")
parser.add_argument("--args", nargs=argparse.REMAINDER)
args = parser.parse_args("--args cmd --arg1 XX -- ZZ".split())
assert args.args == ["cmd", "--arg1", "XX", "--", "ZZ"]


Note that the same code works as expected when using a
positional nargs=argparse.REMAINDER arguments:

import argparse
parser = argparse.ArgumentParser(prog="PROG")
parser.add_argument("args", nargs=argparse.REMAINDER)
args = parser.parse_args("args cmd --arg1 XX ZZ".split())
assert args.args == ["cmd", "--arg1", "XX", "ZZ"]
args = parser.parse_args("args cmd --arg1 XX -- ZZ".split())
assert args.args == ["cmd", "--arg1", "XX", "--", "ZZ"]

But that, of course, does not allow us to have the args value
start with something like "--blah" that looks like an optional
argument.


Hope this helps.

Best regards,
  Jurko Gospodnetić

Might be related to the following issues:

http://bugs.python.org/issue9571
http://bugs.python.org/issue13922