Fix determination of Metadata version (#8933). Patch by Filip Gruszczyński.

dist.py

@@ -1111,7 +1111,8 @@ class DistributionMetadata:
         """Write the PKG-INFO format data to a file object.
         """
         version = '1.0'
-        if self.provides or self.requires or self.obsoletes:
+        if (self.provides or self.requires or self.obsoletes or
+            self.classifiers or self.download_url):
             version = '1.1'
 
         self._write_field(file, 'Metadata-Version', version)

tests/test_dist.py

@@ -245,6 +245,20 @@ class MetadataTestCase(support.TempdirManager, support.EnvironGuard,
         sys.argv[:] = self.argv[1]
         super(MetadataTestCase, self).tearDown()
 
+    def test_classifier(self):
+        attrs = {'name': 'Boa', 'version': '3.0',
+                 'classifiers': ['Programming Language :: Python :: 3']}
+        dist = Distribution(attrs)
+        meta = self.format_metadata(dist)
+        self.assertIn('Metadata-Version: 1.1', meta)
+
+    def test_download_url(self):
+        attrs = {'name': 'Boa', 'version': '3.0',
+                 'download_url': 'http://example.org/boa'}
+        dist = Distribution(attrs)
+        meta = self.format_metadata(dist)
+        self.assertIn('Metadata-Version: 1.1', meta)
+
     def test_long_description(self):
         long_desc = textwrap.dedent("""\
         example::