csv, ctypes, configparser explanations (#5204)

stdlib/configparser.pyi

@@ -45,7 +45,9 @@ class Interpolation:
 
 class BasicInterpolation(Interpolation): ...
 class ExtendedInterpolation(Interpolation): ...
-class LegacyInterpolation(Interpolation): ...
+
+class LegacyInterpolation(Interpolation):
+    def before_get(self, parser: _parser, section: str, option: str, value: str, vars: _section) -> str: ...
 
 class RawConfigParser(_parser):
     _SECT_TMPL: ClassVar[str] = ...  # Undocumented
@@ -188,7 +190,7 @@ class SectionProxy(MutableMapping[str, str]):
     def getboolean(
         self, option: str, fallback: _T = ..., *, raw: bool = ..., vars: Optional[_section] = ...
     ) -> Union[bool, _T]: ...
-    # SectionProxy can have arbitrary attributes when custon converters are used
+    # SectionProxy can have arbitrary attributes when custom converters are used
     def __getattr__(self, key: str) -> Callable[..., Any]: ...
 
 class ConverterMapping(MutableMapping[str, Optional[_converter]]):

stdlib/ctypes/__init__.pyi

@@ -36,15 +36,25 @@ class CDLL(object):
     _name: str = ...
     _handle: int = ...
     _FuncPtr: Type[_FuncPointer] = ...
-    def __init__(
-        self,
-        name: Optional[str],
-        mode: int = ...,
-        handle: Optional[int] = ...,
-        use_errno: bool = ...,
-        use_last_error: bool = ...,
-        winmode: Optional[int] = ...,
-    ) -> None: ...
+    if sys.version_info >= (3, 8):
+        def __init__(
+            self,
+            name: Optional[str],
+            mode: int = ...,
+            handle: Optional[int] = ...,
+            use_errno: bool = ...,
+            use_last_error: bool = ...,
+            winmode: Optional[int] = ...,
+        ) -> None: ...
+    else:
+        def __init__(
+            self,
+            name: Optional[str],
+            mode: int = ...,
+            handle: Optional[int] = ...,
+            use_errno: bool = ...,
+            use_last_error: bool = ...,
+        ) -> None: ...
     def __getattr__(self, name: str) -> _NamedFuncPointer: ...
     def __getitem__(self, name: str) -> _NamedFuncPointer: ...
 
@@ -151,7 +161,7 @@ def byref(obj: _CData, offset: int = ...) -> _CArgObject: ...
 
 _CastT = TypeVar("_CastT", bound=_CanCastTo)
 
-def cast(obj: _UnionT[_CData, _CArgObject, int], type: Type[_CastT]) -> _CastT: ...
+def cast(obj: _UnionT[_CData, _CArgObject, int], typ: Type[_CastT]) -> _CastT: ...
 def create_string_buffer(init: _UnionT[int, bytes], size: Optional[int] = ...) -> Array[c_char]: ...
 
 c_buffer = create_string_buffer

tests/stubtest_whitelists/py36.txt

@@ -20,7 +20,6 @@ collections.AsyncGenerator.ag_running
 collections.UserString.maketrans
 contextlib._GeneratorContextManager.__init__
 copy.PyStringMap
-ctypes.CDLL.__init__
 email.message.MIMEPart.as_string
 enum.Enum._generate_next_value_
 fractions.Fraction.__new__  # overload is too complicated for stubtest to resolve

tests/stubtest_whitelists/py37.txt

@@ -29,7 +29,6 @@ contextvars.Context.get
 contextvars.ContextVar.get
 contextlib.nullcontext  # not a function at runtime
 copy.PyStringMap
-ctypes.CDLL.__init__
 dataclasses.field
 email.message.MIMEPart.as_string
 enum.Enum._generate_next_value_

tests/stubtest_whitelists/py3_common.txt

@@ -120,24 +120,24 @@ collections.abc.Generator.gi_yieldfrom
 collections.abc.Mapping.get
 collections.abc.Sequence.index
 collections.deque.__hash__
-configparser.LegacyInterpolation.before_get
-configparser.SectionProxy.__getattr__
+configparser.SectionProxy.__getattr__  # SectionProxy can have arbitrary attributes when custom converters are used
+# SectionProxy get functions are set in __init__
 configparser.SectionProxy.getboolean
 configparser.SectionProxy.getfloat
 configparser.SectionProxy.getint
+# The Dialect properties are initialized as None in Dialect but their values are enforced in _Dialect
 csv.Dialect.delimiter
 csv.Dialect.doublequote
 csv.Dialect.lineterminator
 csv.Dialect.quoting
 csv.Dialect.skipinitialspace
-ctypes.Array.__iter__
-ctypes.CDLL._FuncPtr
-ctypes.cast
-ctypes.memmove
-ctypes.memset
-ctypes.pointer
-ctypes.string_at
-ctypes.wstring_at
+ctypes.Array.__iter__  # mypy doesn't support using __getitem__ instead of __iter__ so this is here https://github.com/python/mypy/issues/2220
+ctypes.CDLL._FuncPtr  # None at class level but initialized in __init__ to this value
+ctypes.memmove  # CFunctionType
+ctypes.memset  # CFunctionType
+ctypes.pointer  # imported C function
+ctypes.string_at  # docstring argument name is wrong
+ctypes.wstring_at  # docstring argument name is wrong
 dbm.error
 difflib.SequenceMatcher.__init__  # mypy default value for generic parameter issues. See https://github.com/python/mypy/issues/3737
 distutils.command.bdist_packager  # It exists in docs as package name but not in code except as a mention in a comment.