monkey-patch transformers to simplify monkey-patching modeling code (#1877)

* monkey-patch transformers so that monkey-patched modeling code doesnt get overwritten

* unnecessary now

* add comment

src/axolotl/monkeypatch/multipack.py

@@ -94,5 +94,3 @@ def patch_remote(model_name, config_name, modeling_name):
     module_name = model_config.__class__.__module__.replace(config_name, modeling_name)
     modeling_arch = importlib.import_module(module_name)
     modeling_arch._get_unpad_data = get_unpad_data  # pylint: disable=protected-access
-    # workaround to make the patch stick
-    modeling_arch._axolotl_multipack_patch = True  # pylint: disable=protected-access

src/axolotl/monkeypatch/transformers_dynamic_module_utils.py

@@ -0,0 +1,51 @@
+"""Patch transformers.dynamic_module_utils.get_class_in_module to avoid reloading models from disk"""
+
+import importlib
+import os
+import sys
+import typing
+from pathlib import Path
+
+from transformers.file_utils import HF_MODULES_CACHE
+
+
+def _patched_get_class_in_module(
+    class_name: str, module_path: typing.Union[str, os.PathLike]
+) -> typing.Type:
+    """
+    Import a module on the cache directory for modules and extract a class from it.
+
+    Args:
+        class_name (`str`): The name of the class to import.
+        module_path (`str` or `os.PathLike`): The path to the module to import.
+
+    Returns:
+        `typing.Type`: The class looked for.
+    """
+    name = os.path.normpath(module_path)
+    if name.endswith(".py"):
+        name = name[:-3]
+    name = name.replace(os.path.sep, ".")
+    module_spec = importlib.util.spec_from_file_location(
+        name, location=Path(HF_MODULES_CACHE) / module_path
+    )
+    module = sys.modules.get(name)
+    if module is None:
+        module = importlib.util.module_from_spec(module_spec)
+        # insert it into sys.modules before any loading begins
+        sys.modules[name] = module
+        # load in initial case only
+        module_spec.loader.exec_module(module)
+    return getattr(module, class_name)
+
+
+def patch_transformers_dynamic_module_utils():
+    """
+    Recently, transformers started reloading modeling code from disk for models marked trust_remote_code=True.
+    This causes monkey-patches for multipack and liger to be removed.
+    We replace the original function with a version that does not reload the module from disk.
+    See https://github.com/huggingface/transformers/pull/30370#pullrequestreview-2264361581
+    """
+    import transformers
+
+    transformers.dynamic_module_utils.get_class_in_module = _patched_get_class_in_module

src/axolotl/utils/models.py

@@ -43,6 +43,9 @@ from axolotl.monkeypatch.multipack import (
     SUPPORTED_MULTIPACK_MODEL_TYPES,
     patch_for_multipack,
 )
+from axolotl.monkeypatch.transformers_dynamic_module_utils import (
+    patch_transformers_dynamic_module_utils,
+)
 from axolotl.prompt_tokenizers import LLAMA_DEFAULT_EOS_TOKEN
 from axolotl.utils.bench import log_gpu_memory_usage
 from axolotl.utils.chat_templates import chat_templates
@@ -54,6 +57,8 @@ from axolotl.utils.model_shard_quant import load_sharded_model, load_sharded_mod
 
 LOG = logging.getLogger("axolotl")
 
+patch_transformers_dynamic_module_utils()
+
 
 # copied from accelerator.FullyShardedDataParallelPlugin
 def get_module_class_from_name(module, name):