Make it easier to develop without a dev install (#22697)

* Make it easier to develop without a dev install

* Remove ugly hack that doesn't work anyway

utils/check_inits.py

@@ -277,11 +277,20 @@ def check_submodules():
 
     transformers = direct_transformers_import(PATH_TO_TRANSFORMERS)
 
+    import_structure_keys = set(transformers._import_structure.keys())
+    # This contains all the base keys of the _import_structure object defined in the init, but if the user is missing
+    # some optional dependencies, they may not have all of them. Thus we read the init to read all additions and
+    # (potentiall re-) add them.
+    with open(os.path.join(PATH_TO_TRANSFORMERS, "__init__.py"), "r") as f:
+        init_content = f.read()
+    import_structure_keys.update(set(re.findall(r"import_structure\[\"([^\"]*)\"\]", init_content)))
+
     module_not_registered = [
         module
         for module in get_transformers_submodules()
-        if module not in IGNORE_SUBMODULES and module not in transformers._import_structure.keys()
+        if module not in IGNORE_SUBMODULES and module not in import_structure_keys
     ]
+
     if len(module_not_registered) > 0:
         list_of_modules = "\n".join(f"- {module}" for module in module_not_registered)
         raise ValueError(