+import ast
import asyncio
from concurrent.futures import Executor, ProcessPoolExecutor
from contextlib import contextmanager
from blib2to3.pgen2.grammar import Grammar
from blib2to3.pgen2.parse import ParseError
+from _version import get_versions
+
+v = get_versions()
+__version__ = v.get("closest-tag", v["version"])
+__git_version__ = v.get("full-revisionid")
-__version__ = "19.3b0"
DEFAULT_LINE_LENGTH = 88
DEFAULT_EXCLUDES = (
r"/(\.eggs|\.git|\.hg|\.mypy_cache|\.nox|\.tox|\.venv|_build|buck-out|build|dist)/"
)
DEFAULT_INCLUDES = r"\.pyi?$"
-CACHE_DIR = Path(user_cache_dir("black", version=__version__))
+CACHE_DIR = Path(user_cache_dir("black", version=__git_version__))
# types
# set for every version of python.
ASYNC_IDENTIFIERS = 6
ASYNC_KEYWORDS = 7
+ ASSIGNMENT_EXPRESSIONS = 8
+ POS_ONLY_ARGUMENTS = 9
VERSION_TO_FEATURES: Dict[TargetVersion, Set[Feature]] = {
Feature.TRAILING_COMMA_IN_CALL,
Feature.TRAILING_COMMA_IN_DEF,
Feature.ASYNC_KEYWORDS,
+ Feature.ASSIGNMENT_EXPRESSIONS,
+ Feature.POS_ONLY_ARGUMENTS,
},
}
token.DOUBLESTAR,
}
STARS = {token.STAR, token.DOUBLESTAR}
+VARARGS_SPECIALS = STARS | {token.SLASH}
VARARGS_PARENTS = {
syms.arglist,
syms.argument, # double star in arglist
lines (two on module-level).
"""
before, after = self._maybe_empty_lines(current_line)
- before -= self.previous_after
+ before = (
+ # Black should not insert empty lines at the beginning
+ # of the file
+ 0
+ if self.previous_line is None
+ else before - self.previous_after
+ )
self.previous_after = after
self.previous_line = current_line
return before, after
# that, too.
return prevp.prefix
- elif prevp.type in STARS:
+ elif prevp.type in VARARGS_SPECIALS:
if is_vararg(prevp, within=VARARGS_PARENTS | UNPACKING_PARENTS):
return NO
if not prevp or prevp.type == token.LPAR:
return NO
- elif prev.type in {token.EQUAL} | STARS:
+ elif prev.type in {token.EQUAL} | VARARGS_SPECIALS:
return NO
elif p.type == syms.decorator:
check_lpar = True
if check_lpar:
+ if is_walrus_assignment(child):
+ continue
if child.type == syms.atom:
if maybe_make_parens_invisible_in_atom(child, parent=node):
lpar = Leaf(token.LPAR, "")
# make parentheses invisible
first.value = "" # type: ignore
last.value = "" # type: ignore
- if len(node.children) > 1:
- maybe_make_parens_invisible_in_atom(node.children[1], parent=parent)
+ maybe_make_parens_invisible_in_atom(node.children[1], parent=parent)
return False
return True
)
+def unwrap_singleton_parenthesis(node: LN) -> Optional[LN]:
+ """Returns `wrapped` if `node` is of the shape ( wrapped ).
+
+ Parenthesis can be optional. Returns None otherwise"""
+ if len(node.children) != 3:
+ return None
+ lpar, wrapped, rpar = node.children
+ if not (lpar.type == token.LPAR and rpar.type == token.RPAR):
+ return None
+
+ return wrapped
+
+
def is_one_tuple(node: LN) -> bool:
"""Return True if `node` holds a tuple with one element, with or without parens."""
if node.type == syms.atom:
- if len(node.children) != 3:
- return False
-
- lpar, gexp, rpar = node.children
- if not (
- lpar.type == token.LPAR
- and gexp.type == syms.testlist_gexp
- and rpar.type == token.RPAR
- ):
+ gexp = unwrap_singleton_parenthesis(node)
+ if gexp is None or gexp.type != syms.testlist_gexp:
return False
return len(gexp.children) == 2 and gexp.children[1].type == token.COMMA
)
+def is_walrus_assignment(node: LN) -> bool:
+ """Return True iff `node` is of the shape ( test := test )"""
+ inner = unwrap_singleton_parenthesis(node)
+ return inner is not None and inner.type == syms.namedexpr_test
+
+
def is_yield(node: LN) -> bool:
"""Return True if `node` holds a `yield` or `yield from` expression."""
if node.type == syms.yield_expr:
extended iterable unpacking (PEP 3132) and additional unpacking
generalizations (PEP 448).
"""
- if leaf.type not in STARS or not leaf.parent:
+ if leaf.type not in VARARGS_SPECIALS or not leaf.parent:
return False
p = leaf.parent
Currently looking for:
- f-strings;
- - underscores in numeric literals; and
- - trailing commas after * or ** in function signatures and calls.
+ - underscores in numeric literals;
+ - trailing commas after * or ** in function signatures and calls;
+ - positional only arguments in function signatures and lambdas;
"""
features: Set[Feature] = set()
for n in node.pre_order():
if "_" in n.value: # type: ignore
features.add(Feature.NUMERIC_UNDERSCORES)
+ elif n.type == token.SLASH:
+ if n.parent and n.parent.type in {syms.typedargslist, syms.arglist}:
+ features.add(Feature.POS_ONLY_ARGUMENTS)
+
+ elif n.type == token.COLONEQUAL:
+ features.add(Feature.ASSIGNMENT_EXPRESSIONS)
+
elif (
n.type in {syms.typedargslist, syms.arglist}
and n.children
return ", ".join(report) + "."
-def parse_ast(src: str) -> Union[ast3.AST, ast27.AST]:
- for feature_version in (7, 6):
- try:
- return ast3.parse(src, feature_version=feature_version)
- except SyntaxError:
- continue
+def parse_ast(src: str) -> Union[ast.AST, ast3.AST, ast27.AST]:
+ filename = "<unknown>"
+ if sys.version_info >= (3, 8):
+ # TODO: support Python 4+ ;)
+ for minor_version in range(sys.version_info[1], 4, -1):
+ try:
+ return ast.parse(src, filename, feature_version=(3, minor_version))
+ except SyntaxError:
+ continue
+ else:
+ for feature_version in (7, 6):
+ try:
+ return ast3.parse(src, filename, feature_version=feature_version)
+ except SyntaxError:
+ continue
return ast27.parse(src)
+def _fixup_ast_constants(
+ node: Union[ast.AST, ast3.AST, ast27.AST]
+) -> Union[ast.AST, ast3.AST, ast27.AST]:
+ """Map ast nodes deprecated in 3.8 to Constant."""
+ # casts are required until this is released:
+ # https://github.com/python/typeshed/pull/3142
+ if isinstance(node, (ast.Str, ast3.Str, ast27.Str, ast.Bytes, ast3.Bytes)):
+ return cast(ast.AST, ast.Constant(value=node.s))
+ elif isinstance(node, (ast.Num, ast3.Num, ast27.Num)):
+ return cast(ast.AST, ast.Constant(value=node.n))
+ elif isinstance(node, (ast.NameConstant, ast3.NameConstant)):
+ return cast(ast.AST, ast.Constant(value=node.value))
+ return node
+
+
def assert_equivalent(src: str, dst: str) -> None:
"""Raise AssertionError if `src` and `dst` aren't equivalent."""
- def _v(node: Union[ast3.AST, ast27.AST], depth: int = 0) -> Iterator[str]:
+ def _v(node: Union[ast.AST, ast3.AST, ast27.AST], depth: int = 0) -> Iterator[str]:
"""Simple visitor generating strings to compare ASTs by content."""
+
+ node = _fixup_ast_constants(node)
+
yield f"{' ' * depth}{node.__class__.__name__}("
for field in sorted(node._fields):
# TypeIgnore has only one field 'lineno' which breaks this comparison
- if isinstance(node, (ast3.TypeIgnore, ast27.TypeIgnore)):
+ type_ignore_classes = (ast3.TypeIgnore, ast27.TypeIgnore)
+ if sys.version_info >= (3, 8):
+ type_ignore_classes += (ast.TypeIgnore,)
+ if isinstance(node, type_ignore_classes):
break
- # Ignore str kind which is case sensitive / and ignores unicode_literals
- if isinstance(node, (ast3.Str, ast27.Str, ast3.Bytes)) and field == "kind":
- continue
-
try:
value = getattr(node, field)
except AttributeError:
# parentheses and they change the AST.
if (
field == "targets"
- and isinstance(node, (ast3.Delete, ast27.Delete))
- and isinstance(item, (ast3.Tuple, ast27.Tuple))
+ and isinstance(node, (ast.Delete, ast3.Delete, ast27.Delete))
+ and isinstance(item, (ast.Tuple, ast3.Tuple, ast27.Tuple))
):
for item in item.elts:
yield from _v(item, depth + 2)
- elif isinstance(item, (ast3.AST, ast27.AST)):
+ elif isinstance(item, (ast.AST, ast3.AST, ast27.AST)):
yield from _v(item, depth + 2)
- elif isinstance(value, (ast3.AST, ast27.AST)):
+ elif isinstance(value, (ast.AST, ast3.AST, ast27.AST)):
yield from _v(value, depth + 2)
else: