Switch to packaging.tags.compatible_tags

This also has the effect of backfilling minor versions for py*-based
tags, increasing the number of wheels that can match.

Author: chrahunt

src/pip/_internal/pep425tags.py

@@ -9,7 +9,7 @@
 import sysconfig
 import warnings
 
-from pip._vendor.packaging.tags import Tag, mac_platforms
+from pip._vendor.packaging.tags import Tag, compatible_tags, mac_platforms
 
 import pip._internal.utils.glibc
 from pip._internal.utils.compat import get_extension_suffixes
@@ -369,22 +369,26 @@ def get_supported(
                     ("%s%s" % (impl, other_version), abi, arch)
                 )
 
-    # Has binaries, does not use the Python API:
-    for arch in arches:
-        supported.append(('py%s' % (current_version[0]), 'none', arch))
+    if len(current_version) == 1:
+        # XXX: Fake minor version to satisfy requirements of current interface.
+        python_version = (int(current_version[0]), 9)
+    else:
+        python_version = int(current_version[0]), int(current_version[1:])
 
-    # No abi / arch, but requires our implementation:
-    supported.append(('%s%s' % (impl, current_version), 'none', 'any'))
+    interpreter = "{}{}".format(impl, current_version)
 
-    # No abi / arch, generic Python
-    supported.append(('py%s' % (current_version,), 'none', 'any'))
-    supported.append(('py%s' % (current_version[0]), 'none', 'any'))
-    for other_version in other_versions:
-        supported.append(
-            ('py%s' % (other_version,), 'none', 'any')
+    supported.extend(
+        compatible_tags(
+            python_version=python_version,
+            interpreter=interpreter,
+            platforms=arches,
         )
+    )
 
-    return [Tag(*parts) for parts in supported]
+    return [
+        Tag(*parts) if not isinstance(parts, Tag) else parts
+        for parts in supported
+    ]
 
 
 implementation_tag = get_impl_tag()