Parse Python code and perform AST validation.
"""
import ast
+import platform
import sys
-from typing import Iterable, Iterator, List, Set, Union
+from typing import Iterable, Iterator, List, Set, Union, Tuple
# lib2to3 fork
from blib2to3.pytree import Node, Leaf
from black.mode import TargetVersion, Feature, supports_feature
from black.nodes import syms
+_IS_PYPY = platform.python_implementation() == "PyPy"
+
try:
from typed_ast import ast3, ast27
except ImportError:
- if sys.version_info < (3, 8):
+ # Either our python version is too low, or we're on pypy
+ if sys.version_info < (3, 7) or (sys.version_info < (3, 8) and not _IS_PYPY):
print(
"The typed_ast package is required but not installed.\n"
"You can upgrade to Python 3.8+ or install typed_ast with\n"
# Python 3-compatible code, so only try Python 3 grammar.
grammars = []
+ if supports_feature(target_versions, Feature.PATTERN_MATCHING):
+ # Python 3.10+
+ grammars.append(pygram.python_grammar_soft_keywords)
# If we have to parse both, try to parse async as a keyword first
if not supports_feature(target_versions, Feature.ASYNC_IDENTIFIERS):
# Python 3.7+
return code
-def parse_ast(src: str) -> Union[ast.AST, ast3.AST, ast27.AST]:
+def parse_single_version(
+ src: str, version: Tuple[int, int]
+) -> 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
- if ast27.__name__ == "ast":
- raise SyntaxError(
- "The requested source code has invalid Python 3 syntax.\n"
- "If you are trying to format Python 2 files please reinstall Black"
- " with the 'python2' extra: `python3 -m pip install black[python2]`."
- )
- return ast27.parse(src)
+ # typed_ast is needed because of feature version limitations in the builtin ast
+ if sys.version_info >= (3, 8) and version >= (3,):
+ return ast.parse(src, filename, feature_version=version)
+ elif version >= (3,):
+ if _IS_PYPY:
+ return ast3.parse(src, filename)
+ else:
+ return ast3.parse(src, filename, feature_version=version[1])
+ elif version == (2, 7):
+ return ast27.parse(src)
+ raise AssertionError("INTERNAL ERROR: Tried parsing unsupported Python version!")
+
+
+def parse_ast(src: str) -> Union[ast.AST, ast3.AST, ast27.AST]:
+ # TODO: support Python 4+ ;)
+ versions = [(3, minor) for minor in range(3, sys.version_info[1] + 1)]
+
+ if ast27.__name__ != "ast":
+ versions.append((2, 7))
+
+ first_error = ""
+ for version in sorted(versions, reverse=True):
+ try:
+ return parse_single_version(src, version)
+ except SyntaxError as e:
+ if not first_error:
+ first_error = str(e)
+
+ raise SyntaxError(first_error)
def stringify_ast(
yield f"{' ' * depth}{node.__class__.__name__}("
for field in sorted(node._fields): # noqa: F402
- # TypeIgnore has only one field 'lineno' which breaks this comparison
- 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
+ # TypeIgnore will not be present using pypy < 3.8, so need for this
+ if not (_IS_PYPY and sys.version_info < (3, 8)):
+ # TypeIgnore has only one field 'lineno' which breaks this comparison
+ 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
try:
value = getattr(node, field)