Enable code-specific revision for code on the Hub (#23799)

* Enable code-specific revision for code on the Hub

* invalidate old revision

src/transformers/dynamic_module_utils.py

@@ -316,7 +316,7 @@ def get_cached_module_file(
                 )
                 new_files.append(f"{module_needed}.py")
 
-    if len(new_files) > 0:
+    if len(new_files) > 0 and revision is None:
         new_files = "\n".join([f"- {f}" for f in new_files])
         repo_type_str = "" if repo_type is None else f"{repo_type}s/"
         url = f"https://huggingface.co/{repo_type_str}{pretrained_model_name_or_path}"
@@ -340,6 +340,7 @@ def get_class_from_dynamic_module(
     revision: Optional[str] = None,
     local_files_only: bool = False,
     repo_type: Optional[str] = None,
+    code_revision: Optional[str] = None,
     **kwargs,
 ):
     """
@@ -391,6 +392,10 @@ def get_class_from_dynamic_module(
             If `True`, will only try to load the tokenizer configuration from local files.
         repo_type (`str`, *optional*):
             Specify the repo type (useful when downloading from a space for instance).
+        code_revision (`str`, *optional*, defaults to `"main"`):
+            The specific revision to use for the code on the Hub, if the code leaves in a different repository than the
+            rest of the model. It can be a branch name, a tag name, or a commit id, since we use a git-based system for
+            storing models and other artifacts on huggingface.co, so `revision` can be any identifier allowed by git.
 
     <Tip>
 
@@ -415,12 +420,12 @@ def get_class_from_dynamic_module(
     # Catch the name of the repo if it's specified in `class_reference`
     if "--" in class_reference:
         repo_id, class_reference = class_reference.split("--")
-        # Invalidate revision since it's not relevant for this repo
-        revision = "main"
     else:
         repo_id = pretrained_model_name_or_path
     module_file, class_name = class_reference.split(".")
 
+    if code_revision is None and pretrained_model_name_or_path == repo_id:
+        code_revision = revision
     # And lastly we get the class inside our newly created module
     final_module = get_cached_module_file(
         repo_id,
@@ -430,7 +435,7 @@ def get_class_from_dynamic_module(
         resume_download=resume_download,
         proxies=proxies,
         use_auth_token=use_auth_token,
-        revision=revision,
+        revision=code_revision,
         local_files_only=local_files_only,
         repo_type=repo_type,
     )