diff --git a/master/buildbot/config.py b/master/buildbot/config.py
index c95ff405327..c33db5da10a 100644
--- a/master/buildbot/config.py
+++ b/master/buildbot/config.py
@@ -365,7 +365,7 @@ def load_caches(self, filename, config_dict, errors):
                 for (x, y) in valPairs:
                   if (not isinstance(y, int)):
                      errors.addError(
-		     "value for cache size '%s' must be an integer" % x)
+                     "value for cache size '%s' must be an integer" % x)
                 self.caches.update(caches)
 
         if 'buildCacheSize' in config_dict:
diff --git a/master/buildbot/test/unit/test_config.py b/master/buildbot/test/unit/test_config.py
index 30aceac7284..45da51bffff 100644
--- a/master/buildbot/test/unit/test_config.py
+++ b/master/buildbot/test/unit/test_config.py
@@ -551,7 +551,7 @@ def test_load_caches_entries_test(self):
                 dict(caches=dict(foo="1")),
                 self.errors)
         self.assertConfigError(self.errors,
-	                       "value for cache size 'foo' must be an integer")
+                               "value for cache size 'foo' must be an integer")
 
     def test_load_schedulers_defaults(self):
         self.cfg.load_schedulers(self.filename, {}, self.errors)