# -*- coding: utf-8 -*-
import codecs
import warnings
import re
from contextlib import contextmanager
from parso.normalizer import Normalizer, NormalizerConfig, Issue, Rule
from parso.python.tokenize import _get_token_collection
_BLOCK_STMTS = ('if_stmt', 'while_stmt', 'for_stmt', 'try_stmt', 'with_stmt')
_STAR_EXPR_PARENTS = ('testlist_star_expr', 'testlist_comp', 'exprlist')
# This is the maximal block size given by python.
_MAX_BLOCK_SIZE = 20
_MAX_INDENT_COUNT = 100
ALLOWED_FUTURES = (
'nested_scopes', 'generators', 'division', 'absolute_import',
'with_statement', 'print_function', 'unicode_literals', 'generator_stop',
)
_COMP_FOR_TYPES = ('comp_for', 'sync_comp_for')
def _get_rhs_name(node, version):
type_ = node.type
if type_ == "lambdef":
return "lambda"
elif type_ == "atom":
comprehension = _get_comprehension_type(node)
first, second = node.children[:2]
if comprehension is not None:
return comprehension
elif second.type == "dictorsetmaker":
if version < (3, 8):
return "literal"
else:
if second.children[1] == ":" or second.children[0] == "**":
return "dict display"
else:
return "set display"
elif (
first == "("
and (second == ")"
or (len(node.children) == 3 and node.children[1].type == "testlist_comp"))
):
return "tuple"
elif first == "(":
return _get_rhs_name(_remove_parens(node), version=version)
elif first == "[":
return "list"
elif first == "{" and second == "}":
return "dict display"
elif first == "{" and len(node.children) > 2:
return "set display"
elif type_ == "keyword":
if "yield" in node.value:
return "yield expression"
if version < (3, 8):
return "keyword"
else:
return str(node.value)
elif type_ == "operator" and node.value == "...":
return "Ellipsis"
elif type_ == "comparison":
return "comparison"
elif type_ in ("string", "number", "strings"):
return "literal"
elif type_ == "yield_expr":
return "yield expression"
elif type_ == "test":
return "conditional expression"
elif type_ in ("atom_expr", "power"):
if node.children[0] == "await":
return "await expression"
elif node.children[-1].type == "trailer":
trailer = node.children[-1]
if trailer.children[0] == "(":
return "function call"
elif trailer.children[0] == "[":
return "subscript"
elif trailer.children[0] == ".":
return "attribute"
elif (
("expr" in type_ and "star_expr" not in type_) # is a substring
or "_test" in type_
or type_ in ("term", "factor")
):
return "operator"
elif type_ == "star_expr":
return "starred"
elif type_ == "testlist_star_expr":
return "tuple"
elif type_ == "fstring":
return "f-string expression"
return type_ # shouldn't reach here
def _iter_stmts(scope):
"""
Iterates over all statements and splits up simple_stmt.
"""
for child in scope.children:
if child.type == 'simple_stmt':
for child2 in child.children:
if child2.type == 'newline' or child2 == ';':
continue
yield child2
else:
yield child
def _get_comprehension_type(atom):
first, second = atom.children[:2]
if second.type == 'testlist_comp' and second.children[1].type in _COMP_FOR_TYPES:
if first == '[':
return 'list comprehension'
else:
return 'generator expression'
elif second.type == 'dictorsetmaker' and second.children[-1].type in _COMP_FOR_TYPES:
if second.children[1] == ':':
return 'dict comprehension'
else:
return 'set comprehension'
return None
def _is_future_import(import_from):
# It looks like a __future__ import that is relative is still a future
# import. That feels kind of odd, but whatever.
# if import_from.level != 0:
# return False
from_names = import_from.get_from_names()
return [n.value for n in from_names] == ['__future__']
def _remove_parens(atom):
"""
Returns the inner part of an expression like `(foo)`. Also removes nested
parens.
"""
try:
children = atom.children
except AttributeError:
pass
else:
if len(children) == 3 and children[0] == '(':
return _remove_parens(atom.children[1])
return atom
def _skip_parens_bottom_up(node):
"""
Returns an ancestor node of an expression, skipping all levels of parens
bottom-up.
"""
while node.parent is not None:
node = node.parent
if node.type != 'atom' or node.children[0] != '(':
return node
return None
def _iter_params(parent_node):
return (n for n in parent_node.children if n.type == 'param' or n.type == 'operator')
def _is_future_import_first(import_from):
"""
Checks if the import is the first statement of a file.
"""
found_docstring = False
for stmt in _iter_stmts(import_from.get_root_node()):
if stmt.type == 'string' and not found_docstring:
continue
found_docstring = True
if stmt == import_from:
return True
if stmt.type == 'import_from' and _is_future_import(stmt):
continue
return False
def _iter_definition_exprs_from_lists(exprlist):
def check_expr(child):
if child.type == 'atom':
if child.children[0] == '(':
testlist_comp = child.children[1]
if testlist_comp.type == 'testlist_comp':
yield from _iter_definition_exprs_from_lists(testlist_comp)
return
else:
# It's a paren that doesn't do anything, like 1 + (1)
yield from check_expr(testlist_comp)
return
elif child.children[0] == '[':
yield testlist_comp
return
yield child
if exprlist.type in _STAR_EXPR_PARENTS:
for child in exprlist.children[::2]:
yield from check_expr(child)
else:
yield from check_expr(exprlist)
def _get_expr_stmt_definition_exprs(expr_stmt):
exprs = []
for list_ in expr_stmt.children[:-2:2]:
if list_.type in ('testlist_star_expr', 'testlist'):
exprs += _iter_definition_exprs_from_lists(list_)
else:
exprs.append(list_)
return exprs
def _get_for_stmt_definition_exprs(for_stmt):
exprlist = for_stmt.children[1]
return list(_iter_definition_exprs_from_lists(exprlist))
def _is_argument_comprehension(argument):
return argument.children[1].type in _COMP_FOR_TYPES
def _any_fstring_error(version, node):
if version < (3, 9) or node is None:
return False
if node.type == "error_node":
return any(child.type == "fstring_start" for child in node.children)
elif node.type == "fstring":
return True
else:
return node.search_ancestor("fstring")
class _Context:
def __init__(self, node, add_syntax_error, parent_context=None):
self.node = node
self.blocks = []
self.parent_context = parent_context
self._used_name_dict = {}
self._global_names = []
self._local_params_names = []
self._nonlocal_names = []
self._nonlocal_names_in_subscopes = []
self._add_syntax_error = add_syntax_error
def is_async_funcdef(self):
# Stupidly enough async funcdefs can have two different forms,
# depending if a decorator is used or not.
return self.is_function() \
and self.node.parent.type in ('async_funcdef', 'async_stmt')
def is_function(self):
return self.node.type == 'funcdef'
def add_name(self, name):
parent_type = name.parent.type
if parent_type == 'trailer':
# We are only interested in first level names.
return
if parent_type == 'global_stmt':
self._global_names.append(name)
elif parent_type == 'nonlocal_stmt':
self._nonlocal_names.append(name)
elif parent_type == 'funcdef':
self._local_params_names.extend(
[param.name.value for param in name.parent.get_params()]
)
else:
self._used_name_dict.setdefault(name.value, []).append(name)
def finalize(self):
"""
Returns a list of nonlocal names that need to be part of that scope.
"""
self._analyze_names(self._global_names, 'global')
self._analyze_names(self._nonlocal_names, 'nonlocal')
global_name_strs = {n.value: n for n in self._global_names}
for nonlocal_name in self._nonlocal_names:
try:
global_name = global_name_strs[nonlocal_name.value]
except KeyError:
continue
message = "name '%s' is nonlocal and global" % global_name.value
if global_name.start_pos < nonlocal_name.start_pos:
error_name = global_name
else:
error_name = nonlocal_name
self._add_syntax_error(error_name, message)
nonlocals_not_handled = []
for nonlocal_name in self._nonlocal_names_in_subscopes:
search = nonlocal_name.value
if search in self._local_params_names:
continue
if search in global_name_strs or self.parent_context is None:
message = "no binding for nonlocal '%s' found" % nonlocal_name.value
self._add_syntax_error(nonlocal_name, message)
elif not self.is_function() or \
nonlocal_name.value not in self._used_name_dict:
nonlocals_not_handled.append(nonlocal_name)
return self._nonlocal_names + nonlocals_not_handled
def _analyze_names(self, globals_or_nonlocals, type_):
def raise_(message):
self._add_syntax_error(base_name, message % (base_name.value, type_))
params = []
if self.node.type == 'funcdef':
params = self.node.get_params()
for base_name in globals_or_nonlocals:
found_global_or_nonlocal = False
# Somehow Python does it the reversed way.
for name in reversed(self._used_name_dict.get(base_name.value, [])):
if name.start_pos > base_name.start_pos:
# All following names don't have to be checked.
found_global_or_nonlocal = True
parent = name.parent
if parent.type == 'param' and parent.name == name:
# Skip those here, these definitions belong to the next
# scope.
continue
if name.is_definition():
if parent.type == 'expr_stmt' \
and parent.children[1].type == 'annassign':
if found_global_or_nonlocal:
# If it's after the global the error seems to be
# placed there.
base_name = name
raise_("annotated name '%s' can't be %s")
break
else:
message = "name '%s' is assigned to before %s declaration"
else:
message = "name '%s' is used prior to %s declaration"
if not found_global_or_nonlocal:
raise_(message)
# Only add an error for the first occurence.
break
for param in params:
if param.name.value == base_name.value:
raise_("name '%s' is parameter and %s"),
@contextmanager
def add_block(self, node):
self.blocks.append(node)
yield
self.blocks.pop()
def add_context(self, node):
return _Context(node, self._add_syntax_error, parent_context=self)
def close_child_context(self, child_context):
self._nonlocal_names_in_subscopes += child_context.finalize()
class ErrorFinder(Normalizer):
"""
Searches for errors in the syntax tree.
"""
def __init__(self, *args, **kwargs):
super().__init__(*args, **kwargs)
self._error_dict = {}
self.version = self.grammar.version_info
def initialize(self, node):
def create_context(node):
if node is None:
return None
parent_context = create_context(node.parent)
if node.type in ('classdef', 'funcdef', 'file_input'):
return _Context(node, self._add_syntax_error, parent_context)
return parent_context
self.context = create_context(node) or _Context(node, self._add_syntax_error)
self._indentation_count = 0
def visit(self, node):
if node.type == 'error_node':
with self.visit_node(node):
# Don't need to investigate the inners of an error node. We
# might find errors in there that should be ignored, because
# the error node itself already shows that there's an issue.
return ''
return super().visit(node)
@contextmanager
def visit_node(self, node):
self._check_type_rules(node)
if node.type in _BLOCK_STMTS:
with self.context.add_block(node):
if len(self.context.blocks) == _MAX_BLOCK_SIZE:
self._add_syntax_error(node, "too many statically nested blocks")
yield
return
elif node.type == 'suite':
self._indentation_count += 1
if self._indentation_count == _MAX_INDENT_COUNT:
self._add_indentation_error(node.children[1], "too many levels of indentation")
yield
if node.type == 'suite':
self._indentation_count -= 1
elif node.type in ('classdef', 'funcdef'):
context = self.context
self.context = context.parent_context
self.context.close_child_context(context)
def visit_leaf(self, leaf):
if leaf.type == 'error_leaf':
if leaf.token_type in ('INDENT', 'ERROR_DEDENT'):
# Indents/Dedents itself never have a prefix. They are just
# "pseudo" tokens that get removed by the syntax tree later.
# Therefore in case of an error we also have to check for this.
spacing = list(leaf.get_next_leaf()._split_prefix())[-1]
if leaf.token_type == 'INDENT':
message = 'unexpected indent'
else:
message = 'unindent does not match any outer indentation level'
self._add_indentation_error(spacing, message)
else:
if leaf.value.startswith('\\'):
message = 'unexpected character after line continuation character'
else:
match = re.match('\\w{,2}("{1,3}|\'{1,3})', leaf.value)
if match is None:
message = 'invalid syntax'
if (
self.version >= (3, 9)
and leaf.value in _get_token_collection(
self.version
).always_break_tokens
):
message = "f-string: " + message
else:
if len(match.group(1)) == 1:
message = 'EOL while scanning string literal'
else:
message = 'EOF while scanning triple-quoted string literal'
self._add_syntax_error(leaf, message)
return ''
elif leaf.value == ':':
parent = leaf.parent
if parent.type in ('classdef', 'funcdef'):
self.context = self.context.add_context(parent)
# The rest is rule based.
return super().visit_leaf(leaf)
def _add_indentation_error(self, spacing, message):
self.add_issue(spacing, 903, "IndentationError: " + message)
def _add_syntax_error(self, node, message):
self.add_issue(node, 901, "SyntaxError: " + message)
def add_issue(self, node, code, message):
# Overwrite the default behavior.
# Check if the issues are on the same line.
line = node.start_pos[0]
args = (code, message, node)
self._error_dict.setdefault(line, args)
def finalize(self):
self.context.finalize()
for code, message, node in self._error_dict.values():
self.issues.append(Issue(node, code, message))
class IndentationRule(Rule):
code = 903
def _get_message(self, message, node):
message = super()._get_message(message, node)
return "IndentationError: " + message
@ErrorFinder.register_rule(type='error_node')
class _ExpectIndentedBlock(IndentationRule):
message = 'expected an indented block'
def get_node(self, node):
leaf = node.get_next_leaf()
return list(leaf._split_prefix())[-1]
def is_issue(self, node):
# This is the beginning of a suite that is not indented.
return node.children[-1].type == 'newline'
class ErrorFinderConfig(NormalizerConfig):
normalizer_class = ErrorFinder
class SyntaxRule(Rule):
code = 901
def _get_message(self, message, node):
message = super()._get_message(message, node)
if (
"f-string" not in message
and _any_fstring_error(self._normalizer.version, node)
):
message = "f-string: " + message
return "SyntaxError: " + message
@ErrorFinder.register_rule(type='error_node')
class _InvalidSyntaxRule(SyntaxRule):
message = "invalid syntax"
fstring_message = "f-string: invalid syntax"
def get_node(self, node):
return node.get_next_leaf()
def is_issue(self, node):
error = node.get_next_leaf().type != 'error_leaf'
if (
error
and _any_fstring_error(self._normalizer.version, node)
):
self.add_issue(node, message=self.fstring_message)
else:
# Error leafs will be added later as an error.
return error
@ErrorFinder.register_rule(value='await')
class _AwaitOutsideAsync(SyntaxRule):
message = "'await' outside async function"
def is_issue(self, leaf):
return not self._normalizer.context.is_async_funcdef()
def get_error_node(self, node):
# Return the whole await statement.
return node.parent
@ErrorFinder.register_rule(value='break')
class _BreakOutsideLoop(SyntaxRule):
message = "'break' outside loop"
def is_issue(self, leaf):
in_loop = False
for block in self._normalizer.context.blocks:
if block.type in ('for_stmt', 'while_stmt'):
in_loop = True
return not in_loop
@ErrorFinder.register_rule(value='continue')
class _ContinueChecks(SyntaxRule):
message = "'continue' not properly in loop"
message_in_finally = "'continue' not supported inside 'finally' clause"
def is_issue(self, leaf):
in_loop = False
for block in self._normalizer.context.blocks:
if block.type in ('for_stmt', 'while_stmt'):
in_loop = True
if block.type == 'try_stmt':
last_block = block.children[-3]
if (
last_block == "finally"
and leaf.start_pos > last_block.start_pos
and self._normalizer.version < (3, 8)
):
self.add_issue(leaf, message=self.message_in_finally)
return False # Error already added
if not in_loop:
return True
@ErrorFinder.register_rule(value='from')
class _YieldFromCheck(SyntaxRule):
message = "'yield from' inside async function"
def get_node(self, leaf):
return leaf.parent.parent # This is the actual yield statement.
def is_issue(self, leaf):
return leaf.parent.type == 'yield_arg' \
and self._normalizer.context.is_async_funcdef()
@ErrorFinder.register_rule(type='name')
class _NameChecks(SyntaxRule):
message = 'cannot assign to __debug__'
message_none = 'cannot assign to None'
def is_issue(self, leaf):
self._normalizer.context.add_name(leaf)
if leaf.value == '__debug__' and leaf.is_definition():
return True
@ErrorFinder.register_rule(type='string')
class _StringChecks(SyntaxRule):
message = "bytes can only contain ASCII literal characters."
def is_issue(self, leaf):
string_prefix = leaf.string_prefix.lower()
if 'b' in string_prefix \
and any(c for c in leaf.value if ord(c) > 127):
# b'ä'
return True
if 'r' not in string_prefix:
# Raw strings don't need to be checked if they have proper
# escaping.
payload = leaf._get_payload()
if 'b' in string_prefix:
payload = payload.encode('utf-8')
func = codecs.escape_decode
else:
func = codecs.unicode_escape_decode
try:
with warnings.catch_warnings():
# The warnings from parsing strings are not relevant.
warnings.filterwarnings('ignore')
func(payload)
except UnicodeDecodeError as e:
self.add_issue(leaf, message='(unicode error) ' + str(e))
except ValueError as e:
self.add_issue(leaf, message='(value error) ' + str(e))
@ErrorFinder.register_rule(value='*')
class _StarCheck(SyntaxRule):
message = "named arguments must follow bare *"
def is_issue(self, leaf):
params = leaf.parent
if params.type == 'parameters' and params:
after = params.children[params.children.index(leaf) + 1:]
after = [child for child in after
if child not in (',', ')') and not child.star_count]
return len(after) == 0
@ErrorFinder.register_rule(value='**')
class _StarStarCheck(SyntaxRule):
# e.g. {**{} for a in [1]}
# TODO this should probably get a better end_pos including
# the next sibling of leaf.
message = "dict unpacking cannot be used in dict comprehension"
def is_issue(self, leaf):
if leaf.parent.type == 'dictorsetmaker':
comp_for = leaf.get_next_sibling().get_next_sibling()
return comp_for is not None and comp_for.type in _COMP_FOR_TYPES
@ErrorFinder.register_rule(value='yield')
@ErrorFinder.register_rule(value='return')
class _ReturnAndYieldChecks(SyntaxRule):
message = "'return' with value in async generator"
message_async_yield = "'yield' inside async function"
def get_node(self, leaf):
return leaf.parent
def is_issue(self, leaf):
if self._normalizer.context.node.type != 'funcdef':
self.add_issue(self.get_node(leaf), message="'%s' outside function" % leaf.value)
elif self._normalizer.context.is_async_funcdef() \
and any(self._normalizer.context.node.iter_yield_exprs()):
if leaf.value == 'return' and leaf.parent.type == 'return_stmt':
return True
@ErrorFinder.register_rule(type='strings')
class _BytesAndStringMix(SyntaxRule):
# e.g. 's' b''
message = "cannot mix bytes and nonbytes literals"
def _is_bytes_literal(self, string):
if string.type == 'fstring':
return False
return 'b' in string.string_prefix.lower()
def is_issue(self, node):
first = node.children[0]
first_is_bytes = self._is_bytes_literal(first)
for string in node.children[1:]:
if first_is_bytes != self._is_bytes_literal(string):
return True
@ErrorFinder.register_rule(type='import_as_names')
class _TrailingImportComma(SyntaxRule):
# e.g. from foo import a,
message = "trailing comma not allowed without surrounding parentheses"
def is_issue(self, node):
if node.children[-1] == ',' and node.parent.children[-1] != ')':
return True
@ErrorFinder.register_rule(type='import_from')
class _ImportStarInFunction(SyntaxRule):
message = "import * only allowed at module level"
def is_issue(self, node):
return node.is_star_import() and self._normalizer.context.parent_context is not None
@ErrorFinder.register_rule(type='import_from')
class _FutureImportRule(SyntaxRule):
message = "from __future__ imports must occur at the beginning of the file"
def is_issue(self, node):
if _is_future_import(node):
if not _is_future_import_first(node):
return True
for from_name, future_name in node.get_paths():
name = future_name.value
allowed_futures = list(ALLOWED_FUTURES)
if self._normalizer.version >= (3, 7):
allowed_futures.append('annotations')
if name == 'braces':
self.add_issue(node, message="not a chance")
elif name == 'barry_as_FLUFL':
m = "Seriously I'm not implementing this :) ~ Dave"
self.add_issue(node, message=m)
elif name not in allowed_futures:
message = "future feature %s is not defined" % name
self.add_issue(node, message=message)
@ErrorFinder.register_rule(type='star_expr')
class _StarExprRule(SyntaxRule):
message_iterable_unpacking = "iterable unpacking cannot be used in comprehension"
def is_issue(self, node):
def check_delete_starred(node):
while node.parent is not None:
node = node.parent
if node.type == 'del_stmt':
return True
if node.type not in (*_STAR_EXPR_PARENTS, 'atom'):
return False
return False
if self._normalizer.version >= (3, 9):
ancestor = node.parent
else:
ancestor = _skip_parens_bottom_up(node)
# starred expression not in tuple/list/set
if ancestor.type not in (*_STAR_EXPR_PARENTS, 'dictorsetmaker') \
and not (ancestor.type == 'atom' and ancestor.children[0] != '('):
self.add_issue(node, message="can't use starred expression here")
return
if check_delete_starred(node):
if self._normalizer.version >= (3, 9):
self.add_issue(node, message="cannot delete starred")
else:
self.add_issue(node, message="can't use starred expression here")
return
if node.parent.type == 'testlist_comp':
# [*[] for a in [1]]
if node.parent.children[1].type in _COMP_FOR_TYPES:
self.add_issue(node, message=self.message_iterable_unpacking)
@ErrorFinder.register_rule(types=_STAR_EXPR_PARENTS)
class _StarExprParentRule(SyntaxRule):
def is_issue(self, node):
def is_definition(node, ancestor):
if ancestor is None:
return False
type_ = ancestor.type
if type_ == 'trailer':
return False
if type_ == 'expr_stmt':
return node.start_pos < ancestor.children[-1].start_pos
return is_definition(node, ancestor.parent)
if is_definition(node, node.parent):
args = [c for c in node.children if c != ',']
starred = [c for c in args if c.type == 'star_expr']
if len(starred) > 1:
if self._normalizer.version < (3, 9):
message = "two starred expressions in assignment"
else:
message = "multiple starred expressions in assignment"
self.add_issue(starred[1], message=message)
elif starred:
count = args.index(starred[0])
if count >= 256:
message = "too many expressions in star-unpacking assignment"
self.add_issue(starred[0], message=message)
@ErrorFinder.register_rule(type='annassign')
class _AnnotatorRule(SyntaxRule):
# True: int
# {}: float
message = "illegal target for annotation"
def get_node(self, node):
return node.parent
def is_issue(self, node):
type_ = None
lhs = node.parent.children[0]
lhs = _remove_parens(lhs)
try:
children = lhs.children
except AttributeError:
pass
else:
if ',' in children or lhs.type == 'atom' and children[0] == '(':
type_ = 'tuple'
elif lhs.type == 'atom' and children[0] == '[':
type_ = 'list'
trailer = children[-1]
if type_ is None:
if not (lhs.type == 'name'
# subscript/attributes are allowed
or lhs.type in ('atom_expr', 'power')
and trailer.type == 'trailer'
and trailer.children[0] != '('):
return True
else:
# x, y: str
message = "only single target (not %s) can be annotated"
self.add_issue(lhs.parent, message=message % type_)
@ErrorFinder.register_rule(type='argument')
class _ArgumentRule(SyntaxRule):
def is_issue(self, node):
first = node.children[0]
if self._normalizer.version < (3, 8):
# a((b)=c) is valid in <3.8
first = _remove_parens(first)
if node.children[1] == '=' and first.type != 'name':
if first.type == 'lambdef':
# f(lambda: 1=1)
if self._normalizer.version < (3, 8):
message = "lambda cannot contain assignment"
else:
message = 'expression cannot contain assignment, perhaps you meant "=="?'
else:
# f(+x=1)
if self._normalizer.version < (3, 8):
message = "keyword can't be an expression"
else:
message = 'expression cannot contain assignment, perhaps you meant "=="?'
self.add_issue(first, message=message)
if _is_argument_comprehension(node) and node.parent.type == 'classdef':
self.add_issue(node, message='invalid syntax')
@ErrorFinder.register_rule(type='nonlocal_stmt')
class _NonlocalModuleLevelRule(SyntaxRule):
message = "nonlocal declaration not allowed at module level"
def is_issue(self, node):
return self._normalizer.context.parent_context is None
@ErrorFinder.register_rule(type='arglist')
class _ArglistRule(SyntaxRule):
@property
def message(self):
if self._normalizer.version < (3, 7):
return "Generator expression must be parenthesized if not sole argument"
else:
return "Generator expression must be parenthesized"
def is_issue(self, node):
arg_set = set()
kw_only = False
kw_unpacking_only = False
for argument in node.children:
if argument == ',':
continue
if argument.type == 'argument':
first = argument.children[0]
if _is_argument_comprehension(argument) and len(node.children) >= 2:
# a(a, b for b in c)
return True
if first in ('*', '**'):
if first == '*':
if kw_unpacking_only:
# foo(**kwargs, *args)
message = "iterable argument unpacking " \
"follows keyword argument unpacking"
self.add_issue(argument, message=message)
else:
kw_unpacking_only = True
else: # Is a keyword argument.
kw_only = True
if first.type == 'name':
if first.value in arg_set:
# f(x=1, x=2)
message = "keyword argument repeated"
if self._normalizer.version >= (3, 9):
message += ": {}".format(first.value)
self.add_issue(first, message=message)
else:
arg_set.add(first.value)
else:
if kw_unpacking_only:
# f(**x, y)
message = "positional argument follows keyword argument unpacking"
self.add_issue(argument, message=message)
elif kw_only:
# f(x=2, y)
message = "positional argument follows keyword argument"
self.add_issue(argument, message=message)
@ErrorFinder.register_rule(type='parameters')
@ErrorFinder.register_rule(type='lambdef')
class _ParameterRule(SyntaxRule):
# def f(x=3, y): pass
message = "non-default argument follows default argument"
def is_issue(self, node):
param_names = set()
default_only = False
star_seen = False
for p in _iter_params(node):
if p.type == 'operator':
if p.value == '*':
star_seen = True
default_only = False
continue
if p.name.value in param_names:
message = "duplicate argument '%s' in function definition"
self.add_issue(p.name, message=message % p.name.value)
param_names.add(p.name.value)
if not star_seen:
if p.default is None and not p.star_count:
if default_only:
return True
elif p.star_count:
star_seen = True
default_only = False
else:
default_only = True
@ErrorFinder.register_rule(type='try_stmt')
class _TryStmtRule(SyntaxRule):
message = "default 'except:' must be last"
def is_issue(self, try_stmt):
default_except = None
for except_clause in try_stmt.children[3::3]:
if except_clause in ('else', 'finally'):
break
if except_clause == 'except':
default_except = except_clause
elif default_except is not None:
self.add_issue(default_except, message=self.message)
@ErrorFinder.register_rule(type='fstring')
class _FStringRule(SyntaxRule):
_fstring_grammar = None
message_expr = "f-string expression part cannot include a backslash"
message_nested = "f-string: expressions nested too deeply"
message_conversion = "f-string: invalid conversion character: expected 's', 'r', or 'a'"
def _check_format_spec(self, format_spec, depth):
self._check_fstring_contents(format_spec.children[1:], depth)
def _check_fstring_expr(self, fstring_expr, depth):
if depth >= 2:
self.add_issue(fstring_expr, message=self.message_nested)
expr = fstring_expr.children[1]
if '\\' in expr.get_code():
self.add_issue(expr, message=self.message_expr)
children_2 = fstring_expr.children[2]
if children_2.type == 'operator' and children_2.value == '=':
conversion = fstring_expr.children[3]
else:
conversion = children_2
if conversion.type == 'fstring_conversion':
name = conversion.children[1]
if name.value not in ('s', 'r', 'a'):
self.add_issue(name, message=self.message_conversion)
format_spec = fstring_expr.children[-2]
if format_spec.type == 'fstring_format_spec':
self._check_format_spec(format_spec, depth + 1)
def is_issue(self, fstring):
self._check_fstring_contents(fstring.children[1:-1])
def _check_fstring_contents(self, children, depth=0):
for fstring_content in children:
if fstring_content.type == 'fstring_expr':
self._check_fstring_expr(fstring_content, depth)
class _CheckAssignmentRule(SyntaxRule):
def _check_assignment(self, node, is_deletion=False, is_namedexpr=False, is_aug_assign=False):
error = None
type_ = node.type
if type_ == 'lambdef':
error = 'lambda'
elif type_ == 'atom':
first, second = node.children[:2]
error = _get_comprehension_type(node)
if error is None:
if second.type == 'dictorsetmaker':
if self._normalizer.version < (3, 8):
error = 'literal'
else:
if second.children[1] == ':':
error = 'dict display'
else:
error = 'set display'
elif first == "{" and second == "}":
if self._normalizer.version < (3, 8):
error = 'literal'
else:
error = "dict display"
elif first == "{" and len(node.children) > 2:
if self._normalizer.version < (3, 8):
error = 'literal'
else:
error = "set display"
elif first in ('(', '['):
if second.type == 'yield_expr':
error = 'yield expression'
elif second.type == 'testlist_comp':
# ([a, b] := [1, 2])
# ((a, b) := [1, 2])
if is_namedexpr:
if first == '(':
error = 'tuple'
elif first == '[':
error = 'list'
# This is not a comprehension, they were handled
# further above.
for child in second.children[::2]:
self._check_assignment(child, is_deletion, is_namedexpr, is_aug_assign)
else: # Everything handled, must be useless brackets.
self._check_assignment(second, is_deletion, is_namedexpr, is_aug_assign)
elif type_ == 'keyword':
if node.value == "yield":
error = "yield expression"
elif self._normalizer.version < (3, 8):
error = 'keyword'
else:
error = str(node.value)
elif type_ == 'operator':
if node.value == '...':
error = 'Ellipsis'
elif type_ == 'comparison':
error = 'comparison'
elif type_ in ('string', 'number', 'strings'):
error = 'literal'
elif type_ == 'yield_expr':
# This one seems to be a slightly different warning in Python.
message = 'assignment to yield expression not possible'
self.add_issue(node, message=message)
elif type_ == 'test':
error = 'conditional expression'
elif type_ in ('atom_expr', 'power'):
if node.children[0] == 'await':
error = 'await expression'
elif node.children[-2] == '**':
error = 'operator'
else:
# Has a trailer
trailer = node.children[-1]
assert trailer.type == 'trailer'
if trailer.children[0] == '(':
error = 'function call'
elif is_namedexpr and trailer.children[0] == '[':
error = 'subscript'
elif is_namedexpr and trailer.children[0] == '.':
error = 'attribute'
elif type_ == "fstring":
if self._normalizer.version < (3, 8):
error = 'literal'
else:
error = "f-string expression"
elif type_ in ('testlist_star_expr', 'exprlist', 'testlist'):
for child in node.children[::2]:
self._check_assignment(child, is_deletion, is_namedexpr, is_aug_assign)
elif ('expr' in type_ and type_ != 'star_expr' # is a substring
or '_test' in type_
or type_ in ('term', 'factor')):
error = 'operator'
elif type_ == "star_expr":
if is_deletion:
if self._normalizer.version >= (3, 9):
error = "starred"
else:
self.add_issue(node, message="can't use starred expression here")
else:
if self._normalizer.version >= (3, 9):
ancestor = node.parent
else:
ancestor = _skip_parens_bottom_up(node)
if ancestor.type not in _STAR_EXPR_PARENTS and not is_aug_assign \
and not (ancestor.type == 'atom' and ancestor.children[0] == '['):
message = "starred assignment target must be in a list or tuple"
self.add_issue(node, message=message)
self._check_assignment(node.children[1])
if error is not None:
if is_namedexpr:
message = 'cannot use assignment expressions with %s' % error
else:
cannot = "can't" if self._normalizer.version < (3, 8) else "cannot"
message = ' '.join([cannot, "delete" if is_deletion else "assign to", error])
self.add_issue(node, message=message)
@ErrorFinder.register_rule(type='sync_comp_for')
class _CompForRule(_CheckAssignmentRule):
message = "asynchronous comprehension outside of an asynchronous function"
def is_issue(self, node):
expr_list = node.children[1]
if expr_list.type != 'expr_list': # Already handled.
self._check_assignment(expr_list)
return node.parent.children[0] == 'async' \
and not self._normalizer.context.is_async_funcdef()
@ErrorFinder.register_rule(type='expr_stmt')
class _ExprStmtRule(_CheckAssignmentRule):
message = "illegal expression for augmented assignment"
extended_message = "'{target}' is an " + message
def is_issue(self, node):
augassign = node.children[1]
is_aug_assign = augassign != '=' and augassign.type != 'annassign'
if self._normalizer.version <= (3, 8) or not is_aug_assign:
for before_equal in node.children[:-2:2]:
self._check_assignment(before_equal, is_aug_assign=is_aug_assign)
if is_aug_assign:
target = _remove_parens(node.children[0])
# a, a[b], a.b
if target.type == "name" or (
target.type in ("atom_expr", "power")
and target.children[1].type == "trailer"
and target.children[-1].children[0] != "("
):
return False
if self._normalizer.version <= (3, 8):
return True
else:
self.add_issue(
node,
message=self.extended_message.format(
target=_get_rhs_name(node.children[0], self._normalizer.version)
),
)
@ErrorFinder.register_rule(type='with_item')
class _WithItemRule(_CheckAssignmentRule):
def is_issue(self, with_item):
self._check_assignment(with_item.children[2])
@ErrorFinder.register_rule(type='del_stmt')
class _DelStmtRule(_CheckAssignmentRule):
def is_issue(self, del_stmt):
child = del_stmt.children[1]
if child.type != 'expr_list': # Already handled.
self._check_assignment(child, is_deletion=True)
@ErrorFinder.register_rule(type='expr_list')
class _ExprListRule(_CheckAssignmentRule):
def is_issue(self, expr_list):
for expr in expr_list.children[::2]:
self._check_assignment(expr)
@ErrorFinder.register_rule(type='for_stmt')
class _ForStmtRule(_CheckAssignmentRule):
def is_issue(self, for_stmt):
# Some of the nodes here are already used, so no else if
expr_list = for_stmt.children[1]
if expr_list.type != 'expr_list': # Already handled.
self._check_assignment(expr_list)
@ErrorFinder.register_rule(type='namedexpr_test')
class _NamedExprRule(_CheckAssignmentRule):
# namedexpr_test: test [':=' test]
def is_issue(self, namedexpr_test):
# assigned name
first = namedexpr_test.children[0]
def search_namedexpr_in_comp_for(node):
while True:
parent = node.parent
if parent is None:
return parent
if parent.type == 'sync_comp_for' and parent.children[3] == node:
return parent
node = parent
if search_namedexpr_in_comp_for(namedexpr_test):
# [i+1 for i in (i := range(5))]
# [i+1 for i in (j := range(5))]
# [i+1 for i in (lambda: (j := range(5)))()]
message = 'assignment expression cannot be used in a comprehension iterable expression'
self.add_issue(namedexpr_test, message=message)
# defined names
exprlist = list()
def process_comp_for(comp_for):
if comp_for.type == 'sync_comp_for':
comp = comp_for
elif comp_for.type == 'comp_for':
comp = comp_for.children[1]
exprlist.extend(_get_for_stmt_definition_exprs(comp))
def search_all_comp_ancestors(node):
has_ancestors = False
while True:
node = node.search_ancestor('testlist_comp', 'dictorsetmaker')
if node is None:
break
for child in node.children:
if child.type in _COMP_FOR_TYPES:
process_comp_for(child)
has_ancestors = True
break
return has_ancestors
# check assignment expressions in comprehensions
search_all = search_all_comp_ancestors(namedexpr_test)
if search_all:
if self._normalizer.context.node.type == 'classdef':
message = 'assignment expression within a comprehension ' \
'cannot be used in a class body'
self.add_issue(namedexpr_test, message=message)
namelist = [expr.value for expr in exprlist if expr.type == 'name']
if first.type == 'name' and first.value in namelist:
# [i := 0 for i, j in range(5)]
# [[(i := i) for j in range(5)] for i in range(5)]
# [i for i, j in range(5) if True or (i := 1)]
# [False and (i := 0) for i, j in range(5)]
message = 'assignment expression cannot rebind ' \
'comprehension iteration variable %r' % first.value
self.add_issue(namedexpr_test, message=message)
self._check_assignment(first, is_namedexpr=True)