use hasattr to check for components

Author: bedroge

easybuild/framework/easyblock.py

@@ -5033,7 +5033,7 @@ def build_and_install_one(ecdict, init_env):
                 _log.warning("Failed to create build environment dump for easyconfig %s: %s", reprod_spec, err)
 
             # also add any component/extension easyblocks used during the build for reproducibility
-            if app.comp_instances:
+            if hasattr(app, 'comp_instances'):
                 copy_easyblocks_for_reprod([comp for cfg, comp in app.comp_instances], reprod_dir)
             if app.ext_instances:
                 copy_easyblocks_for_reprod(app.ext_instances, reprod_dir)