def _check_new_format(self, node, func):
""" Check the new string formatting. """
# TODO: skip (for now) format nodes which don't have
# an explicit string on the left side of the format operation.
# We do this because our inference engine can't properly handle
# redefinitions of the original string.
# For more details, see issue 287.
#
# Note that there may not be any left side at all, if the format method
# has been assigned to another variable. See issue 351. For example:
#
# fmt = 'some string {}'.format
# fmt('arg')
if isinstance(node.func, astroid.Attribute) and not isinstance(
node.func.expr, astroid.Const
):
return
if node.starargs or node.kwargs:
return
try:
strnode = next(func.bound.infer())
except astroid.InferenceError:
return
if not (isinstance(strnode, astroid.Const) and isinstance(strnode.value, str)):
return
try:
call_site = CallSite.from_call(node)
except astroid.InferenceError:
return
try:
fields, num_args, manual_pos = utils.parse_format_method_string(
strnode.value
)
except utils.IncompleteFormatString:
self.add_message("bad-format-string", node=node)
return
positional_arguments = call_site.positional_arguments
named_arguments = call_site.keyword_arguments
named_fields = {field[0] for field in fields if isinstance(field[0], str)}
if num_args and manual_pos:
self.add_message("format-combined-specification", node=node)
return
check_args = False
# Consider "{[0]} {[1]}" as num_args.
num_args += sum(1 for field in named_fields if field == "")
if named_fields:
for field in named_fields:
if field and field not in named_arguments:
self.add_message(
"missing-format-argument-key", node=node, args=(field,)
)
for field in named_arguments:
if field not in named_fields:
self.add_message(
"unused-format-string-argument", node=node, args=(field,)
)
# num_args can be 0 if manual_pos is not.
num_args = num_args or manual_pos
if positional_arguments or num_args:
empty = any(True for field in named_fields if field == "")
if named_arguments or empty:
# Verify the required number of positional arguments
# only if the .format got at least one keyword argument.
# This means that the format strings accepts both
# positional and named fields and we should warn
# when one of the them is missing or is extra.
check_args = True
else:
check_args = True
if check_args:
# num_args can be 0 if manual_pos is not.
num_args = num_args or manual_pos
if len(positional_arguments) > num_args:
self.add_message("too-many-format-args", node=node)
elif len(positional_arguments) < num_args:
self.add_message("too-few-format-args", node=node)
self._detect_vacuous_formatting(node, positional_arguments)
self._check_new_format_specifiers(node, fields, named_arguments)
def _check_new_format(self, node, func):
""" Check the new string formatting. """
# TODO: skip (for now) format nodes which don't have
# an explicit string on the left side of the format operation.
# We do this because our inference engine can't properly handle
# redefinitions of the original string.
# For more details, see issue 287.
#
# Note that there may not be any left side at all, if the format method
# has been assigned to another variable. See issue 351. For example:
#
# fmt = 'some string {}'.format
# fmt('arg')
if isinstance(node.func, astroid.Attribute) and not isinstance(
node.func.expr, astroid.Const
):
return
if node.starargs or node.kwargs:
return
try:
strnode = next(func.bound.infer())
except astroid.InferenceError:
return
if not (isinstance(strnode, astroid.Const) and isinstance(strnode.value, str)):
return
try:
call_site = CallSite.from_call(node)
except astroid.InferenceError:
return
try:
fields, num_args, manual_pos = utils.parse_format_method_string(
strnode.value
)
except utils.IncompleteFormatString:
self.add_message("bad-format-string", node=node)
return
positional_arguments = call_site.positional_arguments
named_arguments = call_site.keyword_arguments
named_fields = {field[0] for field in fields if isinstance(field[0], str)}
if num_args and manual_pos:
self.add_message("format-combined-specification", node=node)
return
check_args = False
# Consider "{[0]} {[1]}" as num_args.
num_args += sum(1 for field in named_fields if field == "")
if named_fields:
for field in named_fields:
if field and field not in named_arguments:
self.add_message(
"missing-format-argument-key", node=node, args=(field,)
)
for field in named_arguments:
if field not in named_fields:
self.add_message(
"unused-format-string-argument", node=node, args=(field,)
)
# num_args can be 0 if manual_pos is not.
num_args = num_args or manual_pos
if positional_arguments or num_args:
empty = any(True for field in named_fields if field == "")
if named_arguments or empty:
# Verify the required number of positional arguments
# only if the .format got at least one keyword argument.
# This means that the format strings accepts both
# positional and named fields and we should warn
# when one of the them is missing or is extra.
check_args = True
else:
check_args = True
if check_args:
# num_args can be 0 if manual_pos is not.
num_args = num_args or manual_pos
if len(positional_arguments) > num_args:
self.add_message("too-many-format-args", node=node)
elif len(positional_arguments) < num_args:
self.add_message("too-few-format-args", node=node)
self._detect_vacuous_formatting(node, positional_arguments)
self._check_new_format_specifiers(node, fields, named_arguments)