def _set_unknown_flag(self, name, value):
"""Returns value if setting flag |name| to |value| returned True.
Args:
name: str, name of the flag to set.
value: Value to set.
Returns:
Flag value on successful call.
Raises:
UnrecognizedFlagError
IllegalFlagValueError
"""
setter = self.__dict__['__set_unknown']
if setter:
try:
setter(name, value)
return value
except (TypeError, ValueError): # Flag value is not valid.
raise _exceptions.IllegalFlagValueError(
'"{1}" is not valid for --{0}' .format(name, value))
except NameError: # Flag name is not valid.
pass
raise _exceptions.UnrecognizedFlagError(name, value)
def DEFINE_alias( # pylint: disable=invalid-name
name,
original_name,
flag_values=_flagvalues.FLAGS,
module_name=None):
"""Defines an alias flag for an existing one.
Args:
name: str, the flag name.
original_name: str, the original flag name.
flag_values: FlagValues, the FlagValues instance with which the flag will be
registered. This should almost never need to be overridden.
module_name: A string, the name of the module that defines this flag.
Returns:
a handle to defined flag.
Raises:
flags.FlagError:
UnrecognizedFlagError: if the referenced flag doesn't exist.
DuplicateFlagError: if the alias name has been used by some existing flag.
"""
if original_name not in flag_values:
raise _exceptions.UnrecognizedFlagError(original_name)
flag = flag_values[original_name]
class _FlagAlias(_flag.Flag):
"""Overrides Flag class so alias value is copy of original flag value."""
def parse(self, argument):
flag.parse(argument)
self.present += 1
def _parse_from_default(self, value):
# The value was already parsed by the aliased flag, so there is no
# need to call the parser on it a second time.
# Additionally, because of how MultiFlag parses and merges values,
# it isn't possible to delegate to the aliased flag and still get
# the correct values.
return value
@property
def value(self):
return flag.value
@value.setter
def value(self, value):
flag.value = value
help_msg = 'Alias for --%s.' % flag.name
# If alias_name has been used, flags.DuplicatedFlag will be raised.
return DEFINE_flag(
_FlagAlias(flag.parser,
flag.serializer,
name,
flag.default,
help_msg,
boolean=flag.boolean), flag_values, module_name)
def DEFINE_alias(
name,
original_name,
flag_values=_flagvalues.FLAGS, # pylint: disable=invalid-name
module_name=None):
"""Defines an alias flag for an existing one.
Args:
name: str, the flag name.
original_name: str, the original flag name.
flag_values: FlagValues, the FlagValues instance with which the flag will
be registered. This should almost never need to be overridden.
module_name: A string, the name of the module that defines this flag.
Raises:
flags.FlagError:
UnrecognizedFlagError: if the referenced flag doesn't exist.
DuplicateFlagError: if the alias name has been used by some existing flag.
"""
if original_name not in flag_values:
raise _exceptions.UnrecognizedFlagError(original_name)
flag = flag_values[original_name]
class _Parser(_argument_parser.ArgumentParser):
"""The parser for the alias flag calls the original flag parser."""
def parse(self, argument):
flag.parse(argument)
return flag.value
class _FlagAlias(_flag.Flag):
"""Overrides Flag class so alias value is copy of original flag value."""
@property
def value(self):
return flag.value
@value.setter
def value(self, value):
flag.value = value
help_msg = 'Alias for --%s.' % flag.name
# If alias_name has been used, flags.DuplicatedFlag will be raised.
DEFINE_flag(
_FlagAlias(_Parser(),
flag.serializer,
name,
flag.default,
help_msg,
boolean=flag.boolean), flag_values, module_name)
def __call__(self, argv, known_only=False):
"""Parses flags from argv; stores parsed flags into this FlagValues object.
All unparsed arguments are returned.
Args:
argv: a tuple/list of strings.
known_only: bool, if True, parse and remove known flags; return the rest
untouched. Unknown flags specified by --undefok are not returned.
Returns:
The list of arguments not parsed as options, including argv[0].
Raises:
Error: Raised on any parsing error.
TypeError: Raised on passing wrong type of arguments.
ValueError: Raised on flag value parsing error.
"""
if _helpers.is_bytes_or_string(argv):
raise TypeError(
'argv should be a tuple/list of strings, not bytes or string.')
if not argv:
raise ValueError(
'argv cannot be an empty list, and must contain the program name as '
'the first element.')
# This pre parses the argv list for --flagfile=<> options.
program_name = argv[0]
args = self.read_flags_from_files(argv[1:], force_gnu=False)
# Parse the arguments.
unknown_flags, unparsed_args = self._parse_args(args, known_only)
# Handle unknown flags by raising UnrecognizedFlagError.
# Note some users depend on us raising this particular error.
for name, value in unknown_flags:
suggestions = _helpers.get_flag_suggestions(name, list(self))
raise _exceptions.UnrecognizedFlagError(name,
value,
suggestions=suggestions)
self.mark_as_parsed()
self._assert_all_validators()
return [program_name] + unparsed_args
