Typing improvements and updates for code in master

asyncpg/cluster.py

@@ -36,7 +36,7 @@ class _ConnectionSpec(typing_extensions.TypedDict):
     port: str
 
 
-_system = platform.uname().system
+_system: typing_extensions.Final = platform.uname().system
 
 if _system == 'Windows':
     def platform_exe(name: str) -> str:

asyncpg/compat.py

@@ -10,12 +10,13 @@
 import platform
 import sys
 import typing
+import typing_extensions
 
 
 _T = typing.TypeVar('_T')
-PY_36 = sys.version_info >= (3, 6)
-PY_37 = sys.version_info >= (3, 7)
-SYSTEM = platform.uname().system
+PY_36: typing_extensions.Final = sys.version_info >= (3, 6)
+PY_37: typing_extensions.Final = sys.version_info >= (3, 7)
+SYSTEM: typing_extensions.Final = platform.uname().system
 
 
 if SYSTEM == 'Windows':

asyncpg/connect_utils.py

@@ -56,7 +56,7 @@ class _ClientConfiguration(typing.NamedTuple):
     max_cacheable_statement_size: int
 
 
-_system = platform.uname().system
+_system: typing_extensions.Final = platform.uname().system
 
 
 if _system == 'Windows':

asyncpg/connection.py

@@ -320,7 +320,9 @@ def get_settings(self) -> '_cprotocol.ConnectionSettings':
         return self._protocol.get_settings()
 
     def transaction(self, *,
-                    isolation: transaction.IsolationLevels = 'read_committed',
+                    isolation: typing.Optional[
+                        transaction.IsolationLevels
+                    ] = None,
                     readonly: bool = False,
                     deferrable: bool = False) -> transaction.Transaction:
         """Create a :class:`~transaction.Transaction` object.
@@ -1749,7 +1751,7 @@ def _maybe_gc_stmt(
         if (
             stmt.refs == 0
             and not self._stmt_cache.has(
-                (stmt.query, stmt.record_class, bool(stmt.ignore_custom_codec))
+                (stmt.query, stmt.record_class, stmt.ignore_custom_codec)
             )
         ):
             # If low-level `stmt` isn't referenced from any high-level
@@ -2736,14 +2738,17 @@ async def connect(dsn: typing.Optional[str] = None, *,
     )
 
 
+_StatementCacheKey = typing.Tuple[str, typing.Type[_Record], bool]
+
+
 class _StatementCacheEntry:
 
     __slots__ = ('_query', '_statement', '_cache', '_cleanup_cb')
 
     def __init__(
         self,
         cache: '_StatementCache',
-        query: typing.Tuple[str, typing.Type[_Record], bool],
+        query: _StatementCacheKey[_Record],
         statement: '_cprotocol.PreparedStatementState[_Record]'
     ) -> None:
         self._cache = cache
@@ -2783,7 +2788,7 @@ def __init__(self, *, loop: asyncio.AbstractEventLoop,
         # entries dict, whereas the unused one will group in the
         # beginning of it.
         self._entries: collections.OrderedDict[
-            typing.Tuple[str, typing.Type['_cprotocol.Record'], bool],
+            _StatementCacheKey['_cprotocol.Record'],
             _StatementCacheEntry
         ] = collections.OrderedDict()
 
@@ -2811,7 +2816,7 @@ def set_max_lifetime(self, new_lifetime: float) -> None:
 
     def get(
         self,
-        query: typing.Tuple[str, typing.Type[_Record], bool],
+        query: _StatementCacheKey[_Record],
         *,
         promote: bool = True
     ) -> typing.Optional['_cprotocol.PreparedStatementState[_Record]']:
@@ -2837,12 +2842,12 @@ def get(
 
         return entry._statement
 
-    def has(self, query: typing.Tuple[str, typing.Type[_Record], bool]) -> bool:
+    def has(self, query: _StatementCacheKey[_Record]) -> bool:
         return self.get(query, promote=False) is not None
 
     def put(
         self,
-        query: typing.Tuple[str, typing.Type[_Record], bool],
+        query: _StatementCacheKey[_Record],
         statement: '_cprotocol.PreparedStatementState[_Record]'
     ) -> None:
         if not self._max_size:
@@ -2884,7 +2889,7 @@ def _set_entry_timeout(self, entry: _StatementCacheEntry) -> None:
 
     def _new_entry(
         self,
-        query: typing.Tuple[str, typing.Type[_Record], bool],
+        query: _StatementCacheKey[_Record],
         statement: '_cprotocol.PreparedStatementState[_Record]'
     ) -> _StatementCacheEntry:
         entry = _StatementCacheEntry(self, query, statement)

asyncpg/cursor.py

@@ -109,7 +109,7 @@ def __await__(self) -> typing.Generator[
             self._query,
             self._state,
             self._args,
-            self._record_class
+            self._record_class,
         )
         return cursor._init(self._timeout).__await__()
 

asyncpg/introspection.py

@@ -6,12 +6,13 @@
 
 
 import typing
+import typing_extensions
 
 if typing.TYPE_CHECKING:
     from . import protocol
 
 
-_TYPEINFO = '''\
+_TYPEINFO: typing_extensions.Final = '''\
     (
         SELECT
             t.oid                           AS oid,
@@ -102,7 +103,7 @@
 '''
 
 
-INTRO_LOOKUP_TYPES = '''\
+INTRO_LOOKUP_TYPES: typing_extensions.Final = '''\
 WITH RECURSIVE typeinfo_tree(
     oid, ns, name, kind, basetype, has_bin_io, elemtype, elemdelim,
     range_subtype, elem_has_bin_io, attrtypoids, attrnames, depth)
@@ -140,7 +141,7 @@
 '''.format(typeinfo=_TYPEINFO)
 
 
-TYPE_BY_NAME = '''\
+TYPE_BY_NAME: typing_extensions.Final = '''\
 SELECT
     t.oid,
     t.typelem     AS elemtype,
@@ -153,7 +154,7 @@
 '''
 
 
-TYPE_BY_OID = '''\
+TYPE_BY_OID: typing_extensions.Final = '''\
 SELECT
     t.oid,
     t.typelem     AS elemtype,
@@ -166,7 +167,7 @@
 
 
 # 'b' for a base type, 'd' for a domain, 'e' for enum.
-SCALAR_TYPE_KINDS = (b'b', b'd', b'e')
+SCALAR_TYPE_KINDS: typing_extensions.Final = (b'b', b'd', b'e')
 
 
 def is_scalar_type(typeinfo: 'protocol.Record') -> bool:

asyncpg/protocol/protocol.pyi

@@ -18,7 +18,7 @@ from typing import (
     Union,
     overload,
 )
-from typing_extensions import Protocol as _TEProtocol, Literal
+from typing_extensions import Protocol as _TEProtocol, Literal, Final
 
 import asyncpg.pgproto.pgproto
 
@@ -33,9 +33,9 @@ _OtherRecord = TypeVar('_OtherRecord', bound=Record)
 _PreparedStatementState = TypeVar('_PreparedStatementState',
                                   bound=PreparedStatementState[Any])
 
-BUILTIN_TYPE_NAME_MAP: Dict[str, int]
-BUILTIN_TYPE_OID_MAP: Dict[int, str]
-NO_TIMEOUT: _NoTimeoutType
+BUILTIN_TYPE_NAME_MAP: Final[Dict[str, int]]
+BUILTIN_TYPE_OID_MAP: Final[Dict[int, str]]
+NO_TIMEOUT: Final[_NoTimeoutType]
 
 def hashlib_md5(*args: Any, **kwargs: Any) -> Any: ...
 
@@ -186,7 +186,7 @@ class ConnectionSettings(asyncpg.pgproto.pgproto.CodecContext):
         format: Any,
     ) -> Any: ...
     def clear_type_cache(self) -> None: ...
-    def get_data_codec(self, oid: int, format: Any = ...) -> Any: ...
+    def get_data_codec(self, oid: int, format: Any = ..., ignore_custom_codec: bool = ...) -> Any: ...
     def get_text_codec(self) -> CodecInfo: ...
     def register_data_types(self, types: Iterable[Any]) -> None: ...
     def remove_python_codec(
@@ -247,15 +247,15 @@ class PreparedStatementState(Generic[_Record]):
     query: str = ...
     refs: int = ...
     record_class: _TypingType[_Record] = ...
-    ignore_custom_codec: int = ...
+    ignore_custom_codec: bool = ...
     __pyx_vtable__: Any = ...
     def __init__(
         self,
         name: str,
         query: str,
         protocol: BaseProtocol[Any],
         record_class: _TypingType[_Record],
-        ignore_custom_codec: int,
+        ignore_custom_codec: bool,
     ) -> None: ...
     def _get_parameters(self) -> Tuple[Type, ...]: ...
     def _get_attributes(self) -> Tuple[Attribute, ...]: ...

asyncpg/transaction.py

@@ -28,10 +28,16 @@ class TransactionState(enum.Enum):
 IsolationLevels = typing_extensions.Literal['read_committed',
                                             'serializable',
                                             'repeatable_read']
-ISOLATION_LEVELS: typing.Set[IsolationLevels] = {'read_committed',
-                                                 'serializable',
-                                                 'repeatable_read'}
-ISOLATION_LEVELS_BY_VALUE: typing.Dict[str, IsolationLevels] = {
+ISOLATION_LEVELS: typing_extensions.Final[
+    typing.Set[IsolationLevels]
+] = {
+    'read_committed',
+    'serializable',
+    'repeatable_read'
+}
+ISOLATION_LEVELS_BY_VALUE: typing_extensions.Final[
+    typing.Dict[str, IsolationLevels]
+] = {
     'read committed': 'read_committed',
     'serializable': 'serializable',
     'repeatable read': 'repeatable_read',
@@ -50,7 +56,7 @@ class Transaction(connresource.ConnectionResource):
                  '_state', '_nested', '_id', '_managed')
 
     def __init__(self, connection: '_connection.Connection[typing.Any]',
-                 isolation: IsolationLevels,
+                 isolation: typing.Optional[IsolationLevels],
                  readonly: bool, deferrable: bool) -> None:
         super().__init__(connection)
 
@@ -249,7 +255,7 @@ def __repr__(self) -> str:
         attrs = []
         attrs.append('state:{}'.format(self._state.name.lower()))
 
-        attrs.append(self._isolation)
+        attrs.append(str(self._isolation))
         if self._readonly:
             attrs.append('readonly')
         if self._deferrable:

setup.py

@@ -35,7 +35,7 @@
     'pycodestyle~=2.6.0',
     'flake8~=3.8.2',
     'uvloop~=0.14.0;platform_system!="Windows"',
-    'mypy>=0.780'
+    'mypy>=0.790'
 ]
 
 # Dependencies required to build documentation.