diff --git a/runbot/common.py b/runbot/common.py
index 9b61beae..0ac783df 100644
--- a/runbot/common.py
+++ b/runbot/common.py
@@ -28,9 +28,18 @@ class Commit():
     def export(self):
         return self.repo._git_export(self.sha)
 
+    def read_source(self, file, mode='r'):
+        file_path = self._source_path(file)
+        try:
+            with open(file_path, mode) as f:
+                return f.read()
+        except:
+            return False
+
     def __str__(self):
         return '%s:%s' % (self.repo.short_name, self.sha)
 
+
 def fqdn():
     return socket.getfqdn()
 
diff --git a/runbot/models/build_config.py b/runbot/models/build_config.py
index cbe19569..619f4ec3 100644
--- a/runbot/models/build_config.py
+++ b/runbot/models/build_config.py
@@ -337,8 +337,7 @@ class ConfigStep(models.Model):
             docker_source_folder = build._docker_source_folder(commit)
             for manifest_file in commit.repo.manifest_files.split(','):
                 pattern_to_omit.add('*%s' % manifest_file)
-            for (addons_path, module, manifest_file_name) in build._get_available_modules(commit):
-                module = os.path.basename(module_path)
+            for (addons_path, module, _) in build._get_available_modules(commit):
                 if module not in modules_to_install:
                     # we want to omit docker_source_folder/[addons/path/]module/*
                     module_path_in_docker = os.path.join(docker_source_folder, addons_path, module)