Move wheel extension information to remove cycle imports

Author: pradyunsg

src/pip/_internal/index.py

@@ -34,11 +34,11 @@
 from pip._internal.utils.deprecation import deprecated
 from pip._internal.utils.logging import indent_log
 from pip._internal.utils.misc import (
-    ARCHIVE_EXTENSIONS, SUPPORTED_EXTENSIONS, normalize_path,
+    ARCHIVE_EXTENSIONS, SUPPORTED_EXTENSIONS, WHEEL_EXTENSION, normalize_path,
     redact_password_from_url,
 )
 from pip._internal.utils.packaging import check_requires_python
-from pip._internal.wheel import Wheel, wheel_ext
+from pip._internal.wheel import Wheel
 
 __all__ = ['FormatControl', 'PackageFinder']
 
@@ -781,15 +781,15 @@ def _link_package_versions(self, link, search):
                     link, 'unsupported archive format: %s' % ext,
                 )
                 return
-            if "binary" not in search.formats and ext == wheel_ext:
+            if "binary" not in search.formats and ext == WHEEL_EXTENSION:
                 self._log_skipped_link(
                     link, 'No binaries permitted for %s' % search.supplied,
                 )
                 return
             if "macosx10" in link.path and ext == '.zip':
                 self._log_skipped_link(link, 'macosx10 one')
                 return
-            if ext == wheel_ext:
+            if ext == WHEEL_EXTENSION:
                 try:
                     wheel = Wheel(link.filename)
                 except InvalidWheelFilename:
@@ -808,7 +808,7 @@ def _link_package_versions(self, link, search):
                 version = wheel.version
 
         # This should be up by the search.ok_binary check, but see issue 2700.
-        if "source" not in search.formats and ext != wheel_ext:
+        if "source" not in search.formats and ext != WHEEL_EXTENSION:
             self._log_skipped_link(
                 link, 'No sources permitted for %s' % search.supplied,
             )

src/pip/_internal/models/link.py

@@ -4,9 +4,10 @@
 from pip._vendor.six.moves.urllib import parse as urllib_parse
 
 from pip._internal.download import path_to_url
-from pip._internal.utils.misc import redact_password_from_url, splitext
+from pip._internal.utils.misc import (
+    WHEEL_EXTENSION, redact_password_from_url, splitext,
+)
 from pip._internal.utils.models import KeyBasedCompareMixin
-from pip._internal.wheel import wheel_ext
 
 
 class Link(KeyBasedCompareMixin):
@@ -126,7 +127,7 @@ def show_url(self):
 
     @property
     def is_wheel(self):
-        return self.ext == wheel_ext
+        return self.ext == WHEEL_EXTENSION
 
     @property
     def is_artifact(self):

src/pip/_internal/utils/misc.py

@@ -50,19 +50,21 @@
            'renames', 'get_prog',
            'unzip_file', 'untar_file', 'unpack_file', 'call_subprocess',
            'captured_stdout', 'ensure_dir',
-           'ARCHIVE_EXTENSIONS', 'SUPPORTED_EXTENSIONS',
+           'ARCHIVE_EXTENSIONS', 'SUPPORTED_EXTENSIONS', 'WHEEL_EXTENSION',
            'get_installed_version', 'remove_auth_from_url']
 
 
 logger = std_logging.getLogger(__name__)
 
+WHEEL_EXTENSION = '.whl'
 BZ2_EXTENSIONS = ('.tar.bz2', '.tbz')
 XZ_EXTENSIONS = ('.tar.xz', '.txz', '.tlz', '.tar.lz', '.tar.lzma')
-ZIP_EXTENSIONS = ('.zip', '.whl')
+ZIP_EXTENSIONS = ('.zip', WHEEL_EXTENSION)
 TAR_EXTENSIONS = ('.tar.gz', '.tgz', '.tar')
 ARCHIVE_EXTENSIONS = (
     ZIP_EXTENSIONS + BZ2_EXTENSIONS + TAR_EXTENSIONS + XZ_EXTENSIONS)
 SUPPORTED_EXTENSIONS = ZIP_EXTENSIONS + TAR_EXTENSIONS
+
 try:
     import bz2  # noqa
     SUPPORTED_EXTENSIONS += BZ2_EXTENSIONS

src/pip/_internal/wheel.py

@@ -43,8 +43,6 @@
 if MYPY_CHECK_RUNNING:
     from typing import Dict, List, Optional  # noqa: F401
 
-wheel_ext = '.whl'
-
 VERSION_COMPATIBLE = (1, 0)