pkgset: Use highest pickle protocol

Higher protocols should be more efficient in terms of performance and
storage size. Since we don't really care about interoperability with
different python version, we can safely go to the highest version.

Signed-off-by: Lubomír Sedlář <lsedlar@redhat.com>

pungi/phases/pkgset/pkgsets.py

@@ -253,7 +253,7 @@ class PackageSetBase(kobo.log.LoggingBase):
         Saves the current FileCache using the pickle module to `file_path`.
         """
         with open(file_path, 'wb') as f:
-            pickle.dump(self.file_cache, f)
+            pickle.dump(self.file_cache, f, protocol=pickle.HIGHEST_PROTOCOL)
 
 
 class FilelistPackageSet(PackageSetBase):

pungi/phases/pkgset/sources/source_koji.py

@@ -712,7 +712,7 @@ def populate_global_pkgset(compose, koji_wrapper, path_prefix, event):
             else:
                 global_pkgset.fast_merge(pkgset)
         with open(global_pkgset_path, 'wb') as f:
-            data = pickle.dumps(global_pkgset)
+            data = pickle.dumps(global_pkgset, protocol=pickle.HIGHEST_PROTOCOL)
             f.write(data)
 
     # write global package list

pungi/phases/pkgset/sources/source_repos.py

@@ -152,7 +152,7 @@ def populate_global_pkgset(compose, file_list, path_prefix):
         pkgset = pungi.phases.pkgset.pkgsets.FilelistPackageSet(compose.conf["sigkeys"], logger=compose._logger, arches=ALL_ARCHES)
         pkgset.populate(file_list)
         with open(global_pkgset_path, "wb") as f:
-            pickle.dump(pkgset, f)
+            pickle.dump(pkgset, f, protocol=pickle.HIGHEST_PROTOCOL)
 
     # write global package list
     pkgset.save_file_list(compose.paths.work.package_list(arch="global"), remove_path_prefix=path_prefix)

tests/test_pkgset_source_koji.py

@@ -10,6 +10,8 @@ try:
 except ImportError:
     import unittest
 
+from six.moves import cPickle as pickle
+
 sys.path.insert(0, os.path.join(os.path.dirname(__file__), ".."))
 
 from pungi.phases.pkgset.sources import source_koji
@@ -127,7 +129,7 @@ class TestPopulateGlobalPkgset(helpers.PungiTestCase):
             ]
         )
         self.assertItemsEqual(pickle_dumps.call_args_list,
-                              [mock.call(orig_pkgset)])
+                              [mock.call(orig_pkgset, protocol=pickle.HIGHEST_PROTOCOL)])
         with open(self.pkgset_path) as f:
             self.assertEqual(f.read(), 'DATA')
 
@@ -174,7 +176,7 @@ class TestPopulateGlobalPkgset(helpers.PungiTestCase):
         # for each tag, call pkgset.fast_merge once for each variant and once for global pkgset
         self.assertEqual(pkgset.fast_merge.call_count, 2 * (len(self.compose.all_variants.values()) + 1))
         self.assertItemsEqual(pickle_dumps.call_args_list,
-                              [mock.call(orig_pkgset)])
+                              [mock.call(orig_pkgset, protocol=pickle.HIGHEST_PROTOCOL)])
         with open(self.pkgset_path) as f:
             self.assertEqual(f.read(), 'DATA')