Consistently import annotations from future

And use them.

Author: oschwald

maxminddb/__init__.py

@@ -1,7 +1,8 @@
 """Module for reading MaxMind DB files."""
 
-import os
-from typing import IO, AnyStr, Union, cast
+from __future__ import annotations
+
+from typing import IO, TYPE_CHECKING, AnyStr, cast
 
 from .const import (
     MODE_AUTO,
@@ -14,6 +15,9 @@
 from .decoder import InvalidDatabaseError
 from .reader import Reader
 
+if TYPE_CHECKING:
+    import os
+
 try:
     from . import extension as _extension
 except ImportError:
@@ -34,7 +38,7 @@
 
 
 def open_database(
-    database: Union[AnyStr, int, os.PathLike, IO],
+    database: AnyStr | int | os.PathLike | IO,
     mode: int = MODE_AUTO,
 ) -> Reader:
     """Open a MaxMind DB database.

maxminddb/reader.py

@@ -1,5 +1,7 @@
 """Pure-Python reader for the MaxMind DB file format."""
 
+from __future__ import annotations
+
 try:
     import mmap
 except ImportError:
@@ -8,16 +10,20 @@
 import contextlib
 import ipaddress
 import struct
-from collections.abc import Iterator
 from ipaddress import IPv4Address, IPv6Address
-from os import PathLike
-from typing import IO, Any, AnyStr, Optional, Union
+from typing import IO, TYPE_CHECKING, Any, AnyStr
 
 from maxminddb.const import MODE_AUTO, MODE_FD, MODE_FILE, MODE_MEMORY, MODE_MMAP
 from maxminddb.decoder import Decoder
 from maxminddb.errors import InvalidDatabaseError
 from maxminddb.file import FileBuffer
-from maxminddb.types import Record
+
+if TYPE_CHECKING:
+    from collections.abc import Iterator
+    from os import PathLike
+    from types import Self
+
+    from maxminddb.types import Record
 
 _IPV4_MAX_NUM = 2**32
 
@@ -31,16 +37,16 @@ class Reader:
     _DATA_SECTION_SEPARATOR_SIZE = 16
     _METADATA_START_MARKER = b"\xab\xcd\xefMaxMind.com"
 
-    _buffer: Union[bytes, FileBuffer, "mmap.mmap"]
+    _buffer: bytes | FileBuffer | "mmap.mmap"  # noqa: UP037
     _buffer_size: int
     closed: bool
     _decoder: Decoder
-    _metadata: "Metadata"
+    _metadata: Metadata
     _ipv4_start: int
 
     def __init__(
         self,
-        database: Union[AnyStr, int, PathLike, IO],
+        database: AnyStr | int | PathLike | IO,
         mode: int = MODE_AUTO,
     ) -> None:
         """Reader for the MaxMind DB file format.
@@ -133,11 +139,11 @@ def __init__(
             ipv4_start = node
         self._ipv4_start = ipv4_start
 
-    def metadata(self) -> "Metadata":
+    def metadata(self) -> Metadata:
         """Return the metadata associated with the MaxMind DB file."""
         return self._metadata
 
-    def get(self, ip_address: Union[str, IPv6Address, IPv4Address]) -> Optional[Record]:
+    def get(self, ip_address: str | IPv6Address | IPv4Address) -> Record | None:
         """Return the record for the ip_address in the MaxMind DB.
 
         Arguments:
@@ -149,8 +155,8 @@ def get(self, ip_address: Union[str, IPv6Address, IPv4Address]) -> Optional[Reco
 
     def get_with_prefix_len(
         self,
-        ip_address: Union[str, IPv6Address, IPv4Address],
-    ) -> tuple[Optional[Record], int]:
+        ip_address: str | IPv6Address | IPv4Address,
+    ) -> tuple[Record | None, int]:
         """Return a tuple with the record and the associated prefix length.
 
         Arguments:
@@ -279,7 +285,7 @@ def close(self) -> None:
     def __exit__(self, *_) -> None:  # noqa: ANN002
         self.close()
 
-    def __enter__(self) -> "Reader":
+    def __enter__(self) -> Self:
         if self.closed:
             msg = "Attempt to reopen a closed MaxMind DB"
             raise ValueError(msg)

pyproject.toml

@@ -72,9 +72,6 @@ ignore = [
     # Conflicts with D212
     "D213",
 
-    # Don't bother with future imports for type annotations
-    "FA100",
-
     # Magic numbers for HTTP status codes seem ok most of the time.
     "PLR2004",
 

tests/reader_test.py

@@ -1,10 +1,12 @@
+from __future__ import annotations
+
 import ipaddress
 import multiprocessing
 import os
 import pathlib
 import threading
 import unittest
-from typing import Union, cast
+from typing import TYPE_CHECKING, cast
 from unittest import mock
 
 import maxminddb
@@ -23,7 +25,9 @@
     MODE_MMAP,
     MODE_MMAP_EXT,
 )
-from maxminddb.reader import Reader
+
+if TYPE_CHECKING:
+    from maxminddb.reader import Reader
 
 
 def get_reader_from_file_descriptor(filepath: str, mode: int) -> Reader:
@@ -40,18 +44,15 @@ def get_reader_from_file_descriptor(filepath: str, mode: int) -> Reader:
 
 class BaseTestReader(unittest.TestCase):
     mode: int
-    reader_class: Union[
-        type["maxminddb.extension.Reader"],
-        type["maxminddb.reader.Reader"],
-    ]
+    reader_class: type[maxminddb.extension.Reader | maxminddb.reader.Reader]
     use_ip_objects = False
 
     # fork doesn't work on Windows and spawn would involve pickling the reader,
     # which isn't possible.
     if os.name != "nt":
         mp = multiprocessing.get_context("fork")
 
-    def ipf(self, ip: str) -> Union[ipaddress.IPv4Address, ipaddress.IPv6Address, str]:
+    def ipf(self, ip: str) -> ipaddress.IPv4Address | ipaddress.IPv6Address | str:
         if self.use_ip_objects:
             return ipaddress.ip_address(ip)
         return ip
@@ -680,10 +681,7 @@ class TestExtensionReaderWithIPObjects(BaseTestReader):
 class TestAutoReader(BaseTestReader):
     mode = MODE_AUTO
 
-    reader_class: Union[
-        type["maxminddb.extension.Reader"],
-        type["maxminddb.reader.Reader"],
-    ]
+    reader_class: type[maxminddb.extension.Reader | maxminddb.reader.Reader]
     if has_maxminddb_extension():
         reader_class = maxminddb.extension.Reader
     else: