[sqlite3] Use TypeAlias for isolation_level (#14460)

Author: donbarbos

stdlib/_sqlite3.pyi

@@ -16,8 +16,9 @@ from sqlite3 import (
     ProgrammingError as ProgrammingError,
     Row as Row,
     Warning as Warning,
+    _IsolationLevel,
 )
-from typing import Any, Final, Literal, TypeVar, overload
+from typing import Any, Final, TypeVar, overload
 from typing_extensions import TypeAlias
 
 if sys.version_info >= (3, 11):
@@ -225,7 +226,7 @@ if sys.version_info >= (3, 12):
         database: StrOrBytesPath,
         timeout: float = 5.0,
         detect_types: int = 0,
-        isolation_level: Literal["DEFERRED", "EXCLUSIVE", "IMMEDIATE"] | None = "DEFERRED",
+        isolation_level: _IsolationLevel = "DEFERRED",
         check_same_thread: bool = True,
         cached_statements: int = 128,
         uri: bool = False,
@@ -237,7 +238,7 @@ if sys.version_info >= (3, 12):
         database: StrOrBytesPath,
         timeout: float,
         detect_types: int,
-        isolation_level: Literal["DEFERRED", "EXCLUSIVE", "IMMEDIATE"] | None,
+        isolation_level: _IsolationLevel,
         check_same_thread: bool,
         factory: type[_ConnectionT],
         cached_statements: int = 128,
@@ -250,7 +251,7 @@ if sys.version_info >= (3, 12):
         database: StrOrBytesPath,
         timeout: float = 5.0,
         detect_types: int = 0,
-        isolation_level: Literal["DEFERRED", "EXCLUSIVE", "IMMEDIATE"] | None = "DEFERRED",
+        isolation_level: _IsolationLevel = "DEFERRED",
         check_same_thread: bool = True,
         *,
         factory: type[_ConnectionT],
@@ -265,7 +266,7 @@ else:
         database: StrOrBytesPath,
         timeout: float = 5.0,
         detect_types: int = 0,
-        isolation_level: Literal["DEFERRED", "EXCLUSIVE", "IMMEDIATE"] | None = "DEFERRED",
+        isolation_level: _IsolationLevel = "DEFERRED",
         check_same_thread: bool = True,
         cached_statements: int = 128,
         uri: bool = False,
@@ -275,7 +276,7 @@ else:
         database: StrOrBytesPath,
         timeout: float,
         detect_types: int,
-        isolation_level: Literal["DEFERRED", "EXCLUSIVE", "IMMEDIATE"] | None,
+        isolation_level: _IsolationLevel,
         check_same_thread: bool,
         factory: type[_ConnectionT],
         cached_statements: int = 128,
@@ -286,7 +287,7 @@ else:
         database: StrOrBytesPath,
         timeout: float = 5.0,
         detect_types: int = 0,
-        isolation_level: Literal["DEFERRED", "EXCLUSIVE", "IMMEDIATE"] | None = "DEFERRED",
+        isolation_level: _IsolationLevel = "DEFERRED",
         check_same_thread: bool = True,
         *,
         factory: type[_ConnectionT],

stdlib/sqlite3/__init__.pyi

@@ -220,6 +220,8 @@ _SqliteData: TypeAlias = str | ReadableBuffer | int | float | None
 _AdaptedInputData: TypeAlias = _SqliteData | Any
 # The Mapping must really be a dict, but making it invariant is too annoying.
 _Parameters: TypeAlias = SupportsLenAndGetItem[_AdaptedInputData] | Mapping[str, _AdaptedInputData]
+# Controls the legacy transaction handling mode of sqlite3.
+_IsolationLevel: TypeAlias = Literal["DEFERRED", "EXCLUSIVE", "IMMEDIATE"] | None
 
 class _AnyParamWindowAggregateClass(Protocol):
     def step(self, *args: Any) -> object: ...
@@ -285,7 +287,7 @@ class Connection:
     def Warning(self) -> type[Warning]: ...
     @property
     def in_transaction(self) -> bool: ...
-    isolation_level: str | None  # one of '', 'DEFERRED', 'IMMEDIATE' or 'EXCLUSIVE'
+    isolation_level: _IsolationLevel
     @property
     def total_changes(self) -> int: ...
     if sys.version_info >= (3, 12):
@@ -299,26 +301,26 @@ class Connection:
         def __init__(
             self,
             database: StrOrBytesPath,
-            timeout: float = ...,
-            detect_types: int = ...,
-            isolation_level: str | None = ...,
-            check_same_thread: bool = ...,
+            timeout: float = 5.0,
+            detect_types: int = 0,
+            isolation_level: _IsolationLevel = "DEFERRED",
+            check_same_thread: bool = True,
             factory: type[Connection] | None = ...,
-            cached_statements: int = ...,
-            uri: bool = ...,
+            cached_statements: int = 128,
+            uri: bool = False,
             autocommit: bool = ...,
         ) -> None: ...
     else:
         def __init__(
             self,
             database: StrOrBytesPath,
-            timeout: float = ...,
-            detect_types: int = ...,
-            isolation_level: str | None = ...,
-            check_same_thread: bool = ...,
+            timeout: float = 5.0,
+            detect_types: int = 0,
+            isolation_level: _IsolationLevel = "DEFERRED",
+            check_same_thread: bool = True,
             factory: type[Connection] | None = ...,
-            cached_statements: int = ...,
-            uri: bool = ...,
+            cached_statements: int = 128,
+            uri: bool = False,
         ) -> None: ...
 
     def close(self) -> None: ...