Move compatibility logic into its own module

twine/__init__.py

@@ -31,14 +31,10 @@
 __copyright__ = "Copyright 2019 Donald Stufft and individual contributors"
 
 import email.utils
-import sys
 
-if sys.version_info >= (3, 10):
-    import importlib.metadata as importlib_metadata
-else:
-    import importlib_metadata
+from .compat.py39 import importlib
 
-metadata = importlib_metadata.metadata("twine")
+metadata = importlib.metadata.metadata("twine")
 
 
 __title__ = metadata["name"]

twine/cli.py

@@ -13,21 +13,18 @@
 # limitations under the License.
 import argparse
 import logging.config
-import sys
 from typing import Any, List, Tuple
 
-if sys.version_info >= (3, 10):
-    import importlib.metadata as importlib_metadata
-else:
-    import importlib_metadata
-
 import rich
 import rich.highlighter
 import rich.logging
 import rich.theme
 
 import twine
 
+from .compat import py39
+from .compat.py39 import importlib
+
 args = argparse.Namespace()
 
 
@@ -75,16 +72,14 @@ def configure_output() -> None:
 
 
 def list_dependencies_and_versions() -> List[Tuple[str, str]]:
-    deps = [
+    deps = (
         "keyring",
         "pkginfo",
         "requests",
         "requests-toolbelt",
         "urllib3",
-    ]
-    if sys.version_info < (3, 10):
-        deps.append("importlib-metadata")
-    return [(dep, importlib_metadata.version(dep)) for dep in deps]
+    ) + py39.deps
+    return [(dep, importlib.metadata.version(dep)) for dep in deps]
 
 
 def dep_versions() -> str:
@@ -94,7 +89,7 @@ def dep_versions() -> str:
 
 
 def dispatch(argv: List[str]) -> Any:
-    registered_commands = importlib_metadata.entry_points(
+    registered_commands = importlib.metadata.entry_points(
         group="twine.registered_commands"
     )
 

twine/compat/py39.py

@@ -0,0 +1,15 @@
+import sys
+
+if sys.version_info >= (3, 10):
+    import importlib.metadata
+
+    deps = ()
+else:
+
+    class importlib:
+        import importlib_metadata as metadata  # noqa: F401
+
+    deps = ("importlib_metadata",)
+
+
+__all__ = ["importlib", "deps"]

twine/package.py

@@ -18,21 +18,17 @@
 import os
 import re
 import subprocess
-import sys
 from typing import Any, Dict, List, NamedTuple, Optional, Sequence, Tuple, Union, cast
 
-if sys.version_info >= (3, 10):
-    import importlib.metadata as importlib_metadata
-else:
-    import importlib_metadata
-
 import pkginfo
 from rich import print
 
 from twine import exceptions
 from twine import wheel
 from twine import wininst
 
+from .compat.py39 import importlib
+
 DIST_TYPES = {
     "bdist_wheel": wheel.Wheel,
     "bdist_wininst": wininst.WinInst,
@@ -131,7 +127,7 @@ def from_filename(cls, filename: str, comment: Optional[str]) -> "PackageFile":
 
         py_version: Optional[str]
         if dtype == "bdist_egg":
-            (dist,) = importlib_metadata.Distribution.discover(path=[filename])
+            (dist,) = importlib.metadata.Distribution.discover(path=[filename])
             py_version = dist.metadata["Version"]
         elif dtype == "bdist_wheel":
             py_version = cast(wheel.Wheel, meta).py_version