Make winreg import compatible to modern Python

news/7495.bugfix

@@ -0,0 +1 @@
+Make the bundled appdirs compatible with Python 3 on Windows when ``ctypes`` is not available.

src/pip/_internal/utils/appdirs.py

@@ -204,19 +204,22 @@ def _get_win_folder_from_registry(csidl_name):
     registry for this guarantees us the correct answer for all CSIDL_*
     names.
     """
-    import _winreg
+    if PY2:
+        import _winreg as winreg
+    else:
+        import winreg
 
     shell_folder_name = {
         "CSIDL_APPDATA": "AppData",
         "CSIDL_COMMON_APPDATA": "Common AppData",
         "CSIDL_LOCAL_APPDATA": "Local AppData",
     }[csidl_name]
 
-    key = _winreg.OpenKey(
-        _winreg.HKEY_CURRENT_USER,
+    key = winreg.OpenKey(
+        winreg.HKEY_CURRENT_USER,
         r"Software\Microsoft\Windows\CurrentVersion\Explorer\Shell Folders"
     )
-    directory, _type = _winreg.QueryValueEx(key, shell_folder_name)
+    directory, _type = winreg.QueryValueEx(key, shell_folder_name)
     return directory
 
 

tests/unit/test_appdirs.py

@@ -2,6 +2,7 @@
 import os
 import posixpath
 import sys
+import types
 
 import pretend
 
@@ -300,3 +301,78 @@ def test_user_config_dir_linux_home_slash(self, monkeypatch):
         monkeypatch.setattr(sys, "platform", "linux2")
 
         assert appdirs.user_config_dir("pip") == "/.config/pip"
+
+
+class TestGetWinFolder:
+
+    def test_win_folder_ctypes(self, monkeypatch):
+        if sys.platform != 'win32':
+            return
+
+        @pretend.call_recorder
+        def _get_win_folder_from_registry(csidl_name):
+            return "return-value-from-registry"
+
+        @pretend.call_recorder
+        def _get_win_folder_with_ctypes(csidl_name):
+            return "return-value-from-ctypes"
+
+        monkeypatch.setitem(sys.modules, 'ctypes', types.ModuleType('ctypes'))
+        monkeypatch.setattr(
+            appdirs,
+            "_get_win_folder_from_registry",
+            _get_win_folder_from_registry,
+            raising=False,
+        )
+        monkeypatch.setattr(
+            appdirs,
+            "_get_win_folder_with_ctypes",
+            _get_win_folder_with_ctypes,
+            raising=False,
+        )
+
+        assert (
+            appdirs._get_win_folder("place-holder") ==
+            "return-value-from-ctypes"
+        )
+        assert (
+            _get_win_folder_with_ctypes.calls ==
+            [pretend.call("place-holder")]
+        )
+        assert _get_win_folder_from_registry.calls == []
+
+    def test_win_folder_registry(self, monkeypatch):
+        if sys.platform != 'win32':
+            return
+
+        @pretend.call_recorder
+        def _get_win_folder_from_registry(csidl_name):
+            return "return-value-from-registry"
+
+        @pretend.call_recorder
+        def _get_win_folder_with_ctypes(csidl_name):
+            return "return-value-from-ctypes"
+
+        monkeypatch.setitem(sys.modules, 'ctypes', None)
+        monkeypatch.setattr(
+            appdirs,
+            "_get_win_folder_from_registry",
+            _get_win_folder_from_registry,
+            raising=False,
+        )
+        monkeypatch.setattr(
+            appdirs,
+            "_get_win_folder_with_ctypes",
+            _get_win_folder_with_ctypes,
+            raising=False,
+        )
+
+        assert (
+            appdirs._get_win_folder("place-holder") ==
+            "return-value-from-registry"
+        )
+        assert _get_win_folder_with_ctypes.calls == []
+        assert (
+            _get_win_folder_from_registry.calls ==
+            [pretend.call("place-holder")]
+        )