def _check_new_format(self, node, func):
""" Check the new string formatting """
if (isinstance(node.func, astroid.Attribute)
and not isinstance(node.func.expr, astroid.Const)):
return
try:
strnode = next(func.bound.infer())
except astroid.InferenceError:
return
if not isinstance(strnode, astroid.Const):
return
if isinstance(strnode.value, bytes):
self.add_message('ansible-no-format-on-bytestring', node=node)
return
if not isinstance(strnode.value, str):
return
if node.starargs or node.kwargs:
return
try:
num_args = parse_format_method_string(strnode.value)[1]
except utils.IncompleteFormatString:
return
if num_args:
self.add_message('ansible-format-automatic-specification',
node=node)
return
def _check_format_string(self, node, format_arg):
"""Checks that format string tokens match the supplied arguments.
Args:
node (astroid.node_classes.NodeNG): AST node to be checked.
format_arg (int): Index of the format string in the node arguments.
"""
num_args = _count_supplied_tokens(node.args[format_arg + 1:])
if not num_args:
# If no args were supplied the string is not interpolated and can contain
# formatting characters - it's used verbatim. Don't check any further.
return
format_string = node.args[format_arg].value
required_num_args = 0
if isinstance(format_string, bytes):
format_string = format_string.decode()
if isinstance(format_string, str):
try:
if self._format_style == "old":
keyword_args, required_num_args, _, _ = utils.parse_format_string(
format_string)
if keyword_args:
# Keyword checking on logging strings is complicated by
# special keywords - out of scope.
return
elif self._format_style == "new":
(
keyword_arguments,
implicit_pos_args,
explicit_pos_args,
) = utils.parse_format_method_string(format_string)
keyword_args_cnt = len(
set(k for k, l in keyword_arguments
if not isinstance(k, int)))
required_num_args = (keyword_args_cnt + implicit_pos_args +
explicit_pos_args)
else:
self.add_message(
"logging-format-interpolation",
node=node,
args=self._format_style_args,
)
return
except utils.UnsupportedFormatCharacter as ex:
char = format_string[ex.index]
self.add_message(
"logging-unsupported-format",
node=node,
args=(char, ord(char), ex.index),
)
return
except utils.IncompleteFormatString:
self.add_message("logging-format-truncated", node=node)
return
if num_args > required_num_args:
self.add_message("logging-too-many-args", node=node)
elif num_args < required_num_args:
self.add_message("logging-too-few-args", node=node)
def visit_call(self, node):
"""Make sure "print_function" is imported if necessary"""
if (isinstance(node.func, astroid.nodes.Name)
and node.func.name == "print"):
if "print_function" in node.root().future_imports:
def previous(node):
if node is not None:
parent = node.parent
previous = node.previous_sibling()
if previous is None:
return parent
return previous
prev = previous(node)
while prev is not None:
if (isinstance(prev, astroid.nodes.ImportFrom)
and prev.modname == "__future__"
and "print_function"
in (name_alias[0] for name_alias in prev.names)):
return
prev = previous(prev)
self.add_message("print-without-import",
node=node,
confidence=HIGH)
else:
self.add_message("print-without-import",
node=node,
confidence=HIGH)
func = utils.safe_infer(node.func)
if (isinstance(func, astroid.BoundMethod)
and isinstance(func.bound, astroid.Instance)
and func.bound.name in ("str", "unicode", "bytes")):
if func.name == "format":
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:
fields, num_args, manual_pos = (
utils.parse_format_method_string(strnode.value))
except utils.IncompleteFormatString:
self.add_message("bad-format-string", node=node)
if num_args != 0:
self.add_message("implicit-format-spec",
node=node,
confidence=HIGH)
def _check_format_string(self, node, format_arg):
"""Checks that format string tokens match the supplied arguments.
Args:
node (astroid.node_classes.NodeNG): AST node to be checked.
format_arg (int): Index of the format string in the node arguments.
"""
num_args = _count_supplied_tokens(node.args[format_arg + 1 :])
if not num_args:
# If no args were supplied the string is not interpolated and can contain
# formatting characters - it's used verbatim. Don't check any further.
return
format_string = node.args[format_arg].value
if not isinstance(format_string, str):
# If the log format is constant non-string (e.g. logging.debug(5)),
# ensure there are no arguments.
required_num_args = 0
else:
try:
if self._format_style == "old":
keyword_args, required_num_args, _, _ = utils.parse_format_string(
format_string
)
if keyword_args:
# Keyword checking on logging strings is complicated by
# special keywords - out of scope.
return
elif self._format_style == "new":
keyword_arguments, implicit_pos_args, explicit_pos_args = utils.parse_format_method_string(
format_string
)
keyword_args_cnt = len(
set(k for k, l in keyword_arguments if not isinstance(k, int))
)
required_num_args = (
keyword_args_cnt + implicit_pos_args + explicit_pos_args
)
except utils.UnsupportedFormatCharacter as ex:
char = format_string[ex.index]
self.add_message(
"logging-unsupported-format",
node=node,
args=(char, ord(char), ex.index),
)
return
except utils.IncompleteFormatString:
self.add_message("logging-format-truncated", node=node)
return
if num_args > required_num_args:
self.add_message("logging-too-many-args", node=node)
elif num_args < required_num_args:
self.add_message("logging-too-few-args", node=node)
def _check_format_string(self, node, format_arg):
"""Checks that format string tokens match the supplied arguments.
Args:
node (astroid.node_classes.NodeNG): AST node to be checked.
format_arg (int): Index of the format string in the node arguments.
"""
num_args = _count_supplied_tokens(node.args[format_arg + 1:])
if not num_args:
# If no args were supplied, then all format strings are valid -
# don't check any further.
return
format_string = node.args[format_arg].value
if not isinstance(format_string, str):
# If the log format is constant non-string (e.g. logging.debug(5)),
# ensure there are no arguments.
required_num_args = 0
else:
try:
if self._format_style == "%":
keyword_args, required_num_args, _, _ = utils.parse_format_string(
format_string)
if keyword_args:
# Keyword checking on logging strings is complicated by
# special keywords - out of scope.
return
elif self._format_style == "{":
keys, num_args, manual_pos_arg = utils.parse_format_method_string(
format_string)
kargs = len(
set(k for k, l in keys if not isinstance(k, int)))
required_num_args = kargs + num_args + manual_pos_arg
except utils.UnsupportedFormatCharacter as ex:
char = format_string[ex.index]
self.add_message(
"logging-unsupported-format",
node=node,
args=(char, ord(char), ex.index),
)
return
except utils.IncompleteFormatString:
self.add_message("logging-format-truncated", node=node)
return
if num_args > required_num_args:
self.add_message("logging-too-many-args", node=node)
elif num_args < required_num_args:
self.add_message("logging-too-few-args", node=node)
def test_parse_format_method_string():
samples = [
("{}", 1),
("{}:{}", 2),
("{field}", 1),
("{:5}", 1),
("{:10}", 1),
("{field:10}", 1),
("{field:10}{{}}", 1),
("{:5}{!r:10}", 2),
("{:5}{}{{}}{}", 3),
("{0}{1}{0}", 2),
("Coordinates: {latitude}, {longitude}", 2),
("X: {0[0]}; Y: {0[1]}", 1),
("{:*^30}", 1),
("{!r:}", 1),
]
for fmt, count in samples:
keys, num_args, pos_args = utils.parse_format_method_string(fmt)
keyword_args = len(set(k for k, l in keys if not isinstance(k, int)))
assert keyword_args + num_args + pos_args == count
def _check_new_format(self, node, func):
"""Check the new string formatting. """
# Skip 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.
# 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 = astroid.arguments.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)
def _detect_replacable_format_call(self, node: nodes.Const) -> None:
"""Check whether a string is used in a call to format() or '%' and whether it
can be replaced by an f-string
"""
if (isinstance(node.parent, nodes.Attribute)
and node.parent.attrname == "format"):
# Don't warn on referencing / assigning .format without calling it
if not isinstance(node.parent.parent, nodes.Call):
return
if node.parent.parent.args:
for arg in node.parent.parent.args:
# If star expressions with more than 1 element are being used
if isinstance(arg, nodes.Starred):
inferred = utils.safe_infer(arg.value)
if (isinstance(inferred, astroid.List)
and len(inferred.elts) > 1):
return
# Backslashes can't be in f-string expressions
if "\\" in arg.as_string():
return
elif node.parent.parent.keywords:
keyword_args = [
i[0]
for i in utils.parse_format_method_string(node.value)[0]
]
for keyword in node.parent.parent.keywords:
# If keyword is used multiple times
if keyword_args.count(keyword.arg) > 1:
return
keyword = utils.safe_infer(keyword.value)
# If lists of more than one element are being unpacked
if isinstance(keyword, nodes.Dict):
if len(keyword.items) > 1 and len(keyword_args) > 1:
return
# If all tests pass, then raise message
self.add_message(
"consider-using-f-string",
node=node,
line=node.lineno,
col_offset=node.col_offset,
)
elif isinstance(node.parent, nodes.BinOp) and node.parent.op == "%":
# Backslashes can't be in f-string expressions
if "\\" in node.parent.right.as_string():
return
inferred_right = utils.safe_infer(node.parent.right)
# If dicts or lists of length > 1 are used
if isinstance(inferred_right, nodes.Dict):
if len(inferred_right.items) > 1:
return
elif isinstance(inferred_right, nodes.List):
if len(inferred_right.elts) > 1:
return
# If all tests pass, then raise message
self.add_message(
"consider-using-f-string",
node=node,
line=node.lineno,
col_offset=node.col_offset,
)
