Fix upgrade for when running circleci etc

ckan/model/__init__.py

@@ -271,23 +271,25 @@ def upgrade_db(self, version=None):
         assert meta.engine.name in ('postgres', 'postgresql'), \
             'Database migration - only Postgresql engine supported (not %s).' \
                 % meta.engine.name
+        import migrate.versioning.api as mig
+        self.setup_migration_version_control()
+        version_before = mig.db_version(self.metadata.bind, self.migrate_repository)
         from ckan.migration.migrate_package_activity import num_unmigrated
-        num_unmigrated_dataset_activities = num_unmigrated(meta.engine)
-        if num_unmigrated_dataset_activities:
-            print('''
-!!! ERROR !!!
-You have {num_unmigrated} unmigrated package activities.
+        # if still at version 0 there can't be any activities needing migrating
+        if version_before > 0:
+            num_unmigrated_dataset_activities = num_unmigrated(meta.engine)
+            if num_unmigrated_dataset_activities:
+                print('''
+    !!! ERROR !!!
+    You have {num_unmigrated} unmigrated package activities.
 
-You cannot do this db upgrade until you completed the package activity
-migration first. Full instructions for this situation are here:
+    You cannot do this db upgrade until you completed the package activity
+    migration first. Full instructions for this situation are here:
 
-https://github.com/ckan/ckan/wiki/Migrate-package-activity#if-you-tried-to-upgrade-from-ckan-28-or-earlier-to-ckan-29-and-it-stopped-at-paster-db-upgrade
-            '''.format(num_unmigrated=num_unmigrated_dataset_activities))
-            sys.exit(1)
+    https://github.com/ckan/ckan/wiki/Migrate-package-activity#if-you-tried-to-upgrade-from-ckan-28-or-earlier-to-ckan-29-and-it-stopped-at-paster-db-upgrade
+                '''.format(num_unmigrated=num_unmigrated_dataset_activities))
+                sys.exit(1)
 
-        import migrate.versioning.api as mig
-        self.setup_migration_version_control()
-        version_before = mig.db_version(self.metadata.bind, self.migrate_repository)
         mig.upgrade(self.metadata.bind, self.migrate_repository, version=version)
         version_after = mig.db_version(self.metadata.bind, self.migrate_repository)
         if version_after != version_before: