Prefer packaging library if available.

3 files changed, 28 insertions, 7 deletions

diff --git a/setuptools/command/egg_info.py b/setuptools/command/egg_info.py
index de43bf0c..43df87dc 100755
--- a/setuptools/command/egg_info.py
+++ b/setuptools/command/egg_info.py
@@ -10,12 +10,18 @@ import os
 import re
 import sys
 
+try:
+    import packaging.version
+except ImportError:
+    # fallback to vendored version
+    import setuptools._vendor.packaging.version
+    packaging = setuptools._vendor.packaging
+
 from setuptools import Command
 from setuptools.command.sdist import sdist
 from setuptools.compat import basestring, PY3, StringIO
 from setuptools import svn_utils
 from setuptools.command.sdist import walk_revctrl
-from setuptools._vendor.packaging.version import Version
 from pkg_resources import (
     parse_requirements, safe_name, parse_version,
     safe_version, yield_lines, EntryPoint, iter_entry_points, to_filename)
@@ -72,8 +78,9 @@ class egg_info(Command):
         parsed_version = parse_version(self.egg_version)
 
         try:
+            is_version = isinstance(parsed_version, packaging.version.Version)
             spec = (
-                "%s==%s" if isinstance(parsed_version, Version) else "%s===%s"
+                "%s==%s" if is_version else "%s===%s"
             )
             list(
                 parse_requirements(spec % (self.egg_name, self.egg_version))
diff --git a/setuptools/dist.py b/setuptools/dist.py
index ae4ff554..a3a37ee4 100644
--- a/setuptools/dist.py
+++ b/setuptools/dist.py
@@ -13,11 +13,18 @@ from distutils.core import Distribution as _Distribution
 from distutils.errors import (DistutilsOptionError, DistutilsPlatformError,
     DistutilsSetupError)
 
+try:
+    import packaging.version
+except ImportError:
+    # fallback to vendored version
+    import setuptools._vendor.packaging.version
+    packaging = setuptools._vendor.packaging
+
 from setuptools.depends import Require
 from setuptools.compat import basestring, PY2
-from setuptools._vendor.packaging.version import Version, InvalidVersion
 import pkg_resources
 
+
 def _get_unpatched(cls):
     """Protect against re-patching the distutils if reloaded
 
@@ -271,7 +278,8 @@ class Distribution(_Distribution):
 
         if self.metadata.version is not None:
             try:
-                normalized_version = str(Version(self.metadata.version))
+                ver = packaging.version.Version(self.metadata.version)
+                normalized_version = str(ver)
                 if self.metadata.version != normalized_version:
                     warnings.warn(
                         "The version specified requires normalization, "
@@ -281,7 +289,7 @@ class Distribution(_Distribution):
                         )
                     )
                     self.metadata.version = normalized_version
-            except (InvalidVersion, TypeError):
+            except (packaging.version.InvalidVersion, TypeError):
                 warnings.warn(
                     "The version specified (%r) is an invalid version, this "
                     "may not work as expected with newer versions of "
diff --git a/setuptools/tests/test_resources.py b/setuptools/tests/test_resources.py
index 9051b414..8336a85d 100644
--- a/setuptools/tests/test_resources.py
+++ b/setuptools/tests/test_resources.py
@@ -8,6 +8,13 @@ import tempfile
 import shutil
 from unittest import TestCase
 
+try:
+    import packaging.version
+except ImportError:
+    # fallback to vendored version
+    import setuptools._vendor.packaging.version
+    packaging = setuptools._vendor.packaging
+
 import pkg_resources
 from pkg_resources import (parse_requirements, VersionConflict, parse_version,
     Distribution, EntryPoint, Requirement, safe_version, safe_name,
@@ -16,7 +23,6 @@ from pkg_resources import (parse_requirements, VersionConflict, parse_version,
 from setuptools.command.easy_install import (get_script_header, is_sh,
     nt_quote_arg)
 from setuptools.compat import StringIO, iteritems, PY3
-from setuptools._vendor.packaging.version import Specifier
 from .py26compat import skipIf
 
 def safe_repr(obj, short=False):
@@ -339,7 +345,7 @@ class RequirementsTests(TestCase):
         self.assertEqual(r2.extras, ("bar","foo"))  # extras are normalized
         self.assertEqual(hash(r1), hash(r2))
         self.assertEqual(
-            hash(r1), hash(("twisted", Specifier(">=1.2"),
+            hash(r1), hash(("twisted", packaging.version.Specifier(">=1.2"),
                             frozenset(["foo","bar"])))
         )