cgi: various improvements (#3790)

- add max_num_fields to FieldStorage
- fix various types based on default values

stdlib/2and3/cgi.pyi

@@ -3,7 +3,7 @@ from typing import Any, AnyStr, Dict, IO, Iterable, List, Mapping, Optional, Tup
 
 _T = TypeVar('_T', bound=FieldStorage)
 
-def parse(fp: IO[Any] = ..., environ: Mapping[str, str] = ...,
+def parse(fp: Optional[IO[Any]] = ..., environ: Mapping[str, str] = ...,
           keep_blank_values: bool = ..., strict_parsing: bool = ...) -> Dict[str, List[str]]: ...
 if sys.version_info < (3, 8):
     def parse_qs(qs: str, keep_blank_values: bool = ..., strict_parsing: bool = ...) -> Dict[str, List[str]]: ...
@@ -12,7 +12,7 @@ if sys.version_info >= (3, 7):
     def parse_multipart(fp: IO[Any], pdict: Mapping[str, bytes], encoding: str = ..., errors: str = ...) -> Dict[str, List[Any]]: ...
 else:
     def parse_multipart(fp: IO[Any], pdict: Mapping[str, bytes]) -> Dict[str, List[bytes]]: ...
-def parse_header(s: str) -> Tuple[str, Dict[str, str]]: ...
+def parse_header(line: str) -> Tuple[str, Dict[str, str]]: ...
 def test(environ: Mapping[str, str] = ...) -> None: ...
 def print_environ(environ: Mapping[str, str] = ...) -> None: ...
 def print_form(form: Dict[str, Any]) -> None: ...
@@ -21,7 +21,7 @@ def print_environ_usage() -> None: ...
 if sys.version_info < (3,):
     def escape(s: AnyStr, quote: bool = ...) -> AnyStr: ...
 elif sys.version_info < (3, 8):
-    def escape(s: str, quote: bool = ...) -> str: ...
+    def escape(s: str, quote: Optional[bool] = ...) -> str: ...
 
 class MiniFieldStorage:
     # The first five "Any" attributes here are always None, but mypy doesn't support that
@@ -64,10 +64,14 @@ class FieldStorage(object):
     list: Optional[List[Any]]
     value: Union[None, bytes, List[Any]]
 
-    if sys.version_info >= (3, 0):
-        def __init__(self, fp: IO[Any] = ..., headers: Mapping[str, str] = ..., outerboundary: bytes = ...,
+    if sys.version_info >= (3, 6):
+        def __init__(self, fp: Optional[IO[Any]] = ..., headers: Optional[Mapping[str, str]] = ..., outerboundary: bytes = ...,
                      environ: Mapping[str, str] = ..., keep_blank_values: int = ..., strict_parsing: int = ...,
-                     limit: int = ..., encoding: str = ..., errors: str = ...) -> None: ...
+                     limit: Optional[int] = ..., encoding: str = ..., errors: str = ..., max_num_fields: Optional[int] = ...) -> None: ...
+    elif sys.version_info >= (3, 0):
+        def __init__(self, fp: Optional[IO[Any]] = ..., headers: Optional[Mapping[str, str]] = ..., outerboundary: bytes = ...,
+                     environ: Mapping[str, str] = ..., keep_blank_values: int = ..., strict_parsing: int = ...,
+                     limit: Optional[int] = ..., encoding: str = ..., errors: str = ...) -> None: ...
     else:
         def __init__(self, fp: IO[Any] = ..., headers: Mapping[str, str] = ..., outerboundary: bytes = ...,
                      environ: Mapping[str, str] = ..., keep_blank_values: int = ..., strict_parsing: int = ...) -> None: ...

tests/stubtest_whitelists/py35.txt

@@ -17,7 +17,6 @@ asyncio.runners
 asyncio.tasks.Task.__init__
 bdb.GENERATOR_AND_COROUTINE_FLAGS
 builtins.str.maketrans
-cgi.escape
 cmath.log
 codecs.StreamRecoder.seek
 collections.Reversible

tests/stubtest_whitelists/py36.txt

@@ -9,7 +9,6 @@ asyncio.protocols.BufferedProtocol
 asyncio.runners
 asyncio.tasks.Task._wakeup
 builtins.str.maketrans
-cgi.escape
 cmath.log
 codecs.StreamRecoder.seek
 collections.AsyncGenerator.ag_await

tests/stubtest_whitelists/py37.txt

@@ -22,7 +22,6 @@ asyncio.selector_events.BaseSelectorEventLoop.create_unix_server
 builtins.dict.get
 builtins.reversed
 builtins.str.maketrans
-cgi.escape
 cmath.log
 collections.AsyncGenerator.ag_await
 collections.AsyncGenerator.ag_code

tests/stubtest_whitelists/py3_common.txt

@@ -125,9 +125,6 @@ bz2.BZ2File.readinto
 bz2.BZ2File.readlines
 bz2.BZ2File.write
 bz2.BZ2File.writelines
-cgi.FieldStorage.__init__
-cgi.parse
-cgi.parse_header
 codecs.BufferedIncrementalDecoder.decode
 codecs.CodecInfo.decode
 codecs.CodecInfo.encode