Declare support for Python 3.10 (#2562)

[etc/vim.git] / src / black / parsing.py

diff --git a/src/black/parsing.py b/src/black/parsing.py
index 8e9feea9120db796afdf980b10ddc5e7864cebd0..ee6aae1e7ff9db26be2f5f4c439a25d31baf2b7d 100644 (file)
--- a/src/black/parsing.py
+++ b/src/black/parsing.py
@@ -2,8 +2,9 @@
 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
@@ -15,10 +16,13 @@ from blib2to3.pgen2.parse import ParseError
 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"
@@ -59,6 +63,9 @@ def get_grammars(target_versions: Set[TargetVersion]) -> List[Grammar]:
 
     # 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+
@@ -106,28 +113,39 @@ def lib2to3_unparse(node: Node) -> str:
     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(
@@ -140,12 +158,14 @@ 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)