csv: annotate keyword arguments in various functions and methods

stdlib/_csv.pyi

@@ -41,9 +41,45 @@ class _writer:
     def writerow(self, row: Iterable[Any]) -> Any: ...
     def writerows(self, rows: Iterable[Iterable[Any]]) -> None: ...
 
-def writer(csvfile: SupportsWrite[str], dialect: _DialectLike = ..., **fmtparams: Any) -> _writer: ...
-def reader(csvfile: Iterable[str], dialect: _DialectLike = ..., **fmtparams: Any) -> _reader: ...
-def register_dialect(name: str, dialect: Any = ..., **fmtparams: Any) -> None: ...
+def writer(
+    csvfile: SupportsWrite[str],
+    dialect: _DialectLike = ...,
+    *,
+    delimiter: str = ...,
+    quotechar: str | None = ...,
+    escapechar: str | None = ...,
+    doublequote: bool = ...,
+    skipinitialspace: bool = ...,
+    lineterminator: str = ...,
+    quoting: _QuotingType = ...,
+    strict: bool = ...,
+) -> _writer: ...
+def reader(
+    csvfile: Iterable[str],
+    dialect: _DialectLike = ...,
+    *,
+    delimiter: str = ...,
+    quotechar: str | None = ...,
+    escapechar: str | None = ...,
+    doublequote: bool = ...,
+    skipinitialspace: bool = ...,
+    lineterminator: str = ...,
+    quoting: _QuotingType = ...,
+    strict: bool = ...,
+) -> _reader: ...
+def register_dialect(
+    name: str,
+    dialect: Any = ...,
+    *,
+    delimiter: str = ...,
+    quotechar: str | None = ...,
+    escapechar: str | None = ...,
+    doublequote: bool = ...,
+    skipinitialspace: bool = ...,
+    lineterminator: str = ...,
+    quoting: _QuotingType = ...,
+    strict: bool = ...,
+) -> None: ...
 def unregister_dialect(name: str) -> None: ...
 def get_dialect(name: str) -> Dialect: ...
 def list_dialects() -> list[str]: ...

stdlib/csv.pyi

@@ -91,8 +91,15 @@ class DictReader(Generic[_T], Iterator[_DictReadMapping[_T, str]]):
         restkey: str | None = ...,
         restval: str | None = ...,
         dialect: _DialectLike = ...,
-        *args: Any,
-        **kwds: Any,
+        *,
+        delimiter: str = ...,
+        quotechar: str | None = ...,
+        escapechar: str | None = ...,
+        doublequote: bool = ...,
+        skipinitialspace: bool = ...,
+        lineterminator: str = ...,
+        quoting: _QuotingType = ...,
+        strict: bool = ...,
     ) -> None: ...
     @overload
     def __init__(
@@ -102,8 +109,15 @@ class DictReader(Generic[_T], Iterator[_DictReadMapping[_T, str]]):
         restkey: str | None = ...,
         restval: str | None = ...,
         dialect: _DialectLike = ...,
-        *args: Any,
-        **kwds: Any,
+        *,
+        delimiter: str = ...,
+        quotechar: str | None = ...,
+        escapechar: str | None = ...,
+        doublequote: bool = ...,
+        skipinitialspace: bool = ...,
+        lineterminator: str = ...,
+        quoting: _QuotingType = ...,
+        strict: bool = ...,
     ) -> None: ...
     def __iter__(self: Self) -> Self: ...
     def __next__(self) -> _DictReadMapping[_T, str]: ...
@@ -120,8 +134,15 @@ class DictWriter(Generic[_T]):
         restval: Any | None = ...,
         extrasaction: Literal["raise", "ignore"] = ...,
         dialect: _DialectLike = ...,
-        *args: Any,
-        **kwds: Any,
+        *,
+        delimiter: str = ...,
+        quotechar: str | None = ...,
+        escapechar: str | None = ...,
+        doublequote: bool = ...,
+        skipinitialspace: bool = ...,
+        lineterminator: str = ...,
+        quoting: _QuotingType = ...,
+        strict: bool = ...,
     ) -> None: ...
     if sys.version_info >= (3, 8):
         def writeheader(self) -> Any: ...

tests/stubtest_allowlists/py3_common.txt

@@ -78,6 +78,8 @@ csv.Dialect.doublequote
 csv.Dialect.lineterminator
 csv.Dialect.quoting
 csv.Dialect.skipinitialspace
+csv.DictReader.__init__  # runtime sig has *args but will error if more than 5 positional args are supplied
+csv.DictWriter.__init__  # runtime sig has *args but will error if more than 5 positional args are supplied
 ctypes.Array.__iter__  # mypy doesn't support using __getitem__ instead of __iter__ so this is here https://github.com/python/mypy/issues/2220
 ctypes.Array._type_  # _type_ and _length_ are abstract, https://github.com/python/typeshed/pull/6361
 ctypes.Array._length_