Merge branch 'main' into brain-typing-cast

ChangeLog

@@ -11,12 +11,22 @@ What's New in astroid 2.6.3?
 ============================
 Release date: TBA
 
+
+* Fix a bad inferenece type for yield values inside of a derived class.
+
+  Closes PyCQA/astroid#1090
+
 * Fix a crash when the node is a 'Module' in the brain builtin inference
 
   Closes PyCQA/pylint#4671
 
 * Added support to infer return type of typing.cast()
 
+* Fix issues when inferring match variables
+
+  Closes PyCQA/pylint#4685
+
+
 What's New in astroid 2.6.2?
 ============================
 Release date: 2021-06-30
@@ -31,6 +41,7 @@ Release date: 2021-06-30
   Closes PyCQA/pylint#4631
   Closes #1080
 
+
 What's New in astroid 2.6.1?
 ============================
 Release date: 2021-06-29

astroid/as_string.py

@@ -317,7 +317,7 @@ def visit_joinedstr(self, node):
         # Try to find surrounding quotes that don't appear at all in the string.
         # Because the formatted values inside {} can't contain backslash (\)
         # using a triple quote is sometimes necessary
-        for quote in ["'", '"', '"""', "'''"]:
+        for quote in ("'", '"', '"""', "'''"):
             if quote not in string:
                 break
 

astroid/bases.py

@@ -26,7 +26,7 @@
 import collections
 
 from astroid import context as contextmod
-from astroid import util
+from astroid import decorators, util
 from astroid.const import BUILTINS, PY310_PLUS
 from astroid.exceptions import (
     AstroidTypeError,
@@ -543,9 +543,14 @@ class Generator(BaseInstance):
 
     special_attributes = util.lazy_descriptor(objectmodel.GeneratorModel)
 
-    def __init__(self, parent=None):
+    def __init__(self, parent=None, generator_initial_context=None):
         super().__init__()
         self.parent = parent
+        self._call_context = contextmod.copy_context(generator_initial_context)
+
+    @decorators.cached
+    def infer_yield_types(self):
+        yield from self.parent.infer_yield_result(self._call_context)
 
     def callable(self):
         return False

astroid/builder.py

@@ -334,7 +334,7 @@ def _find_statement_by_line(node, line):
       can be found.
     :rtype:  astroid.bases.NodeNG or None
     """
-    if isinstance(node, (nodes.ClassDef, nodes.FunctionDef)):
+    if isinstance(node, (nodes.ClassDef, nodes.FunctionDef, nodes.MatchCase)):
         # This is an inaccuracy in the AST: the nodes that can be
         # decorated do not carry explicit information on which line
         # the actual definition (class/def), but .fromline seems to

astroid/const.py

@@ -15,8 +15,8 @@ class Context(enum.Enum):
 
 
 # TODO Remove in 3.0 in favor of Context
-Load = Context.Load  # pylint: disable=invalid-name
-Store = Context.Store  # pylint: disable=invalid-name
-Del = Context.Del  # pylint: disable=invalid-name
+Load = Context.Load
+Store = Context.Store
+Del = Context.Del
 
 BUILTINS = builtins.__name__  # Could be just 'builtins' ?

astroid/interpreter/_import/spec.py

@@ -129,7 +129,7 @@ def find_module(self, modname, module_parts, processed, submodule_path):
 
         for entry in submodule_path:
             package_directory = os.path.join(entry, modname)
-            for suffix in [".py", importlib.machinery.BYTECODE_SUFFIXES[0]]:
+            for suffix in (".py", importlib.machinery.BYTECODE_SUFFIXES[0]):
                 package_file_name = "__init__" + suffix
                 file_path = os.path.join(package_directory, package_file_name)
                 if os.path.isfile(file_path):

astroid/node_classes.py

@@ -36,10 +36,11 @@
 import abc
 import itertools
 import pprint
+import sys
 import typing
 from functools import lru_cache
 from functools import singledispatch as _singledispatch
-from typing import ClassVar, Optional
+from typing import Callable, ClassVar, Generator, Optional
 
 from astroid import as_string, bases
 from astroid import context as contextmod
@@ -55,10 +56,10 @@
 )
 from astroid.manager import AstroidManager
 
-try:
+if sys.version_info >= (3, 8):
+    # pylint: disable=no-name-in-module
     from typing import Literal
-except ImportError:
-    # typing.Literal was added in Python 3.8
+else:
     from typing_extensions import Literal
 
 
@@ -1385,7 +1386,6 @@ class Arguments(mixins.AssignTypeMixin, NodeNG):
     #  - we expose 'annotation', a list with annotations for
     #    for each normal argument. If an argument doesn't have an
     #    annotation, its value will be None.
-    # pylint: disable=too-many-instance-attributes
     _astroid_fields = (
         "args",
         "defaults",
@@ -5026,6 +5026,16 @@ def postinit(
         self.patterns = patterns
         self.rest = rest
 
+    assigned_stmts: Callable[
+        [
+            "MatchMapping",
+            AssignName,
+            Optional[contextmod.InferenceContext],
+            Literal[None],
+        ],
+        Generator[NodeNG, None, None],
+    ]
+
 
 class MatchClass(Pattern):
     """Class representing a :class:`ast.MatchClass` node.
@@ -5098,6 +5108,16 @@ def __init__(
     def postinit(self, *, name: Optional[AssignName]) -> None:
         self.name = name
 
+    assigned_stmts: Callable[
+        [
+            "MatchStar",
+            AssignName,
+            Optional[contextmod.InferenceContext],
+            Literal[None],
+        ],
+        Generator[NodeNG, None, None],
+    ]
+
 
 class MatchAs(mixins.AssignTypeMixin, Pattern):
     """Class representing a :class:`ast.MatchAs` node.
@@ -5144,6 +5164,16 @@ def postinit(
         self.pattern = pattern
         self.name = name
 
+    assigned_stmts: Callable[
+        [
+            "MatchAs",
+            AssignName,
+            Optional[contextmod.InferenceContext],
+            Literal[None],
+        ],
+        Generator[NodeNG, None, None],
+    ]
+
 
 class MatchOr(Pattern):
     """Class representing a :class:`ast.MatchOr` node.

astroid/protocols.py

@@ -28,6 +28,8 @@
 import collections
 import itertools
 import operator as operator_mod
+import sys
+from typing import Generator, Optional
 
 from astroid import arguments, bases
 from astroid import context as contextmod
@@ -41,6 +43,12 @@
     NoDefault,
 )
 
+if sys.version_info >= (3, 8):
+    # pylint: disable=no-name-in-module
+    from typing import Literal
+else:
+    from typing_extensions import Literal
+
 raw_building = util.lazy_import("raw_building")
 objects = util.lazy_import("objects")
 
@@ -481,22 +489,8 @@ def _infer_context_manager(self, mgr, context):
             # It doesn't interest us.
             raise InferenceError(node=func)
 
-        # Get the first yield point. If it has multiple yields,
-        # then a RuntimeError will be raised.
+        yield next(inferred.infer_yield_types())
 
-        possible_yield_points = func.nodes_of_class(nodes.Yield)
-        # Ignore yields in nested functions
-        yield_point = next(
-            (node for node in possible_yield_points if node.scope() == func), None
-        )
-        if yield_point:
-            if not yield_point.value:
-                const = nodes.Const(None)
-                const.parent = yield_point
-                const.lineno = yield_point.lineno
-                yield const
-            else:
-                yield from yield_point.value.infer(context=context)
     elif isinstance(inferred, bases.Instance):
         try:
             enter = next(inferred.igetattr("__enter__", context=context))
@@ -785,3 +779,58 @@ def _determine_starred_iteration_lookups(starred, target, lookups):
 
 
 nodes.Starred.assigned_stmts = starred_assigned_stmts
+
+
+@decorators.yes_if_nothing_inferred
+def match_mapping_assigned_stmts(
+    self: nodes.MatchMapping,
+    node: nodes.AssignName,
+    context: Optional[contextmod.InferenceContext] = None,
+    assign_path: Literal[None] = None,
+) -> Generator[nodes.NodeNG, None, None]:
+    """Return empty generator (return -> raises StopIteration) so inferred value
+    is Uninferable.
+    """
+    return
+    yield  # pylint: disable=unreachable
+
+
+nodes.MatchMapping.assigned_stmts = match_mapping_assigned_stmts
+
+
+@decorators.yes_if_nothing_inferred
+def match_star_assigned_stmts(
+    self: nodes.MatchStar,
+    node: nodes.AssignName,
+    context: Optional[contextmod.InferenceContext] = None,
+    assign_path: Literal[None] = None,
+) -> Generator[nodes.NodeNG, None, None]:
+    """Return empty generator (return -> raises StopIteration) so inferred value
+    is Uninferable.
+    """
+    return
+    yield  # pylint: disable=unreachable
+
+
+nodes.MatchStar.assigned_stmts = match_star_assigned_stmts
+
+
+@decorators.yes_if_nothing_inferred
+def match_as_assigned_stmts(
+    self: nodes.MatchAs,
+    node: nodes.AssignName,
+    context: Optional[contextmod.InferenceContext] = None,
+    assign_path: Literal[None] = None,
+) -> Generator[nodes.NodeNG, None, None]:
+    """Infer MatchAs as the Match subject if it's the only MatchCase pattern
+    else raise StopIteration to yield Uninferable.
+    """
+    if (
+        isinstance(self.parent, nodes.MatchCase)
+        and isinstance(self.parent.parent, nodes.Match)
+        and self.pattern is None
+    ):
+        yield self.parent.parent.subject
+
+
+nodes.MatchAs.assigned_stmts = match_as_assigned_stmts

astroid/rebuilder.py

@@ -45,18 +45,18 @@
     overload,
 )
 
-try:
-    from typing import Final
-except ImportError:
-    # typing.Final was added in Python 3.8
-    from typing_extensions import Final
-
 from astroid import node_classes, nodes
 from astroid._ast import ParserModule, get_parser_module, parse_function_type_comment
 from astroid.const import PY37_PLUS, PY38_PLUS, PY39_PLUS, Context
 from astroid.manager import AstroidManager
 from astroid.node_classes import NodeNG
 
+if sys.version_info >= (3, 8):
+    # pylint: disable=no-name-in-module
+    from typing import Final
+else:
+    from typing_extensions import Final
+
 if TYPE_CHECKING:
     import ast
 
@@ -85,7 +85,6 @@
 
 # noinspection PyMethodMayBeStatic
 class TreeRebuilder:
-    # pylint: disable=no-self-use
     """Rebuilds the _ast tree to become an Astroid tree"""
 
     def __init__(

astroid/scoped_nodes.py

@@ -1708,6 +1708,21 @@ def is_generator(self):
         """
         return bool(next(self._get_yield_nodes_skip_lambdas(), False))
 
+    def infer_yield_result(self, context=None):
+        """Infer what the function yields when called
+
+        :returns: What the function yields
+        :rtype: iterable(NodeNG or Uninferable) or None
+        """
+        for yield_ in self.nodes_of_class(node_classes.Yield):
+            if yield_.value is None:
+                const = node_classes.Const(None)
+                const.parent = yield_
+                const.lineno = yield_.lineno
+                yield const
+            elif yield_.scope() == self:
+                yield from yield_.value.infer(context=context)
+
     def infer_call_result(self, caller=None, context=None):
         """Infer what the function returns when called.
 
@@ -1719,7 +1734,7 @@ def infer_call_result(self, caller=None, context=None):
                 generator_cls = bases.AsyncGenerator
             else:
                 generator_cls = bases.Generator
-            result = generator_cls(self)
+            result = generator_cls(self, generator_initial_context=context)
             yield result
             return
         # This is really a gigantic hack to work around metaclass generators
@@ -2516,7 +2531,7 @@ def _metaclass_lookup_attribute(self, name, context):
         implicit_meta = self.implicit_metaclass()
         context = contextmod.copy_context(context)
         metaclass = self.metaclass(context=context)
-        for cls in {implicit_meta, metaclass}:
+        for cls in (implicit_meta, metaclass):
             if cls and cls != self and isinstance(cls, ClassDef):
                 cls_attributes = self._get_attribute_from_metaclass(cls, name, context)
                 attrs.update(set(cls_attributes))

pylintrc

@@ -21,6 +21,8 @@ persistent=yes
 # usually to register additional checkers.
 load-plugins=
     pylint.extensions.check_elif,
+    pylint.extensions.bad_builtin,
+    pylint.extensions.code_style,
 
 # Use multiple processes to speed up Pylint.
 jobs=1
@@ -48,7 +50,7 @@ output-format=text
 files-output=no
 
 # Tells whether to display a full report or only the messages
-reports=yes
+reports=no
 
 # Python expression which should return a note less than 10 (10 is the highest
 # note). You have access to the variables errors warning, statement which

requirements_test_pre_commit.txt

@@ -1,5 +1,5 @@
 black==21.6b0
-pylint==2.8.2
+pylint==2.9.3
 isort==5.8.0
 flake8==3.9.2
 mypy==0.910