Support Sequence Classification-Update loader_utils.py

Better Error Handlings.
Safer exec() Usage: Extracts mappings without modifying global scope.
Cleaner Readability & Reduced Redundancy
Support Sequence ClassificationSupport Sequence Classification

unsloth/models/loader_utils.py

@@ -12,114 +12,128 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+import requests
 from .mapper import INT_TO_FLOAT_MAPPER, FLOAT_TO_INT_MAPPER, MAP_TO_UNSLOTH_16bit
-# https://github.com/huggingface/transformers/pull/26037 allows 4 bit loading!
 from packaging.version import Version
-from transformers import __version__ as transformers_version
+from transformers import __version__ as transformers_version, AutoModelForSequenceClassification
+
 transformers_version = Version(transformers_version)
 SUPPORTS_FOURBIT = transformers_version >= Version("4.37")
 
+def patch_for_sequence_classification(model, num_labels=2, device_map=None):
+    """
+    Patch a model to support sequence classification.
+
+    Args:
+        model: The base model (e.g., BERT, RoBERTa).
+        num_labels: The number of labels for classification.
+        device_map: Specifies device placement for efficient training.
+
+    Returns:
+        The patched model for sequence classification.
+    """
+    if not hasattr(model, "config") or not hasattr(model.config, "_name_or_path"):
+        raise ValueError("Invalid model object. Ensure it's a valid Hugging Face model.")
+
+    return AutoModelForSequenceClassification.from_pretrained(
+        model.config._name_or_path,
+        num_labels=num_labels,
+        device_map=device_map,
+    )
+
 
-def __get_model_name(
-    model_name,
-    load_in_4bit = True,
-    INT_TO_FLOAT_MAPPER  = None,
-    FLOAT_TO_INT_MAPPER  = None,
-    MAP_TO_UNSLOTH_16bit = None,
-):
-    model_name = str(model_name)
-    lower_model_name = model_name.lower()
+def __get_model_name(model_name, load_in_4bit, INT_TO_FLOAT_MAPPER, FLOAT_TO_INT_MAPPER, MAP_TO_UNSLOTH_16bit):
+    """
+    Helper function to get the correct model name based on 4-bit compatibility.
 
-    if not SUPPORTS_FOURBIT and lower_model_name in INT_TO_FLOAT_MAPPER:
+    Args:
+        model_name (str): The model name (e.g., "mistral-7b").
+        load_in_4bit (bool): Whether to load in 4-bit.
+        INT_TO_FLOAT_MAPPER, FLOAT_TO_INT_MAPPER, MAP_TO_UNSLOTH_16bit (dict): Mappers for compatibility.
 
-        model_name = INT_TO_FLOAT_MAPPER[lower_model_name]
+    Returns:
+        str: Mapped model name or None if unchanged.
+    """
+    model_name = model_name.lower()
+
+    if not SUPPORTS_FOURBIT and model_name in INT_TO_FLOAT_MAPPER:
         print(
-            f"Unsloth: Your transformers version of {transformers_version} does not support native "\
-            f"4bit loading.\nThe minimum required version is 4.37.\n"\
-            f'Try `pip install --upgrade "transformers>=4.37"`\n'\
-            f"to obtain the latest transformers build, then restart this session.\n"\
-            f"For now, we shall load `{model_name}` instead (still 4bit, just slower downloading)."
+            f"Unsloth: Your transformers version {transformers_version} does not support native 4-bit loading.\n"
+            f"The minimum required version is 4.37. Try `pip install --upgrade \"transformers>=4.37\"`\n"
+            f"For now, we shall load `{INT_TO_FLOAT_MAPPER[model_name]}` instead (still 4-bit, just slower)."
         )
-        return model_name
-
-    elif not load_in_4bit and lower_model_name in INT_TO_FLOAT_MAPPER:
+        return INT_TO_FLOAT_MAPPER[model_name]
 
-        new_model_name = INT_TO_FLOAT_MAPPER[lower_model_name]
-        # logger.warning_once(
-        #     f"Unsloth: You passed in `{model_name}` which is a 4bit model, yet you set\n"\
-        #     f"`load_in_4bit = False`. We shall load `{new_model_name}` instead."
-        # )
-        return new_model_name
+    if not load_in_4bit:
+        return INT_TO_FLOAT_MAPPER.get(model_name) or MAP_TO_UNSLOTH_16bit.get(model_name)
 
-    elif not load_in_4bit and lower_model_name in MAP_TO_UNSLOTH_16bit:
+    if SUPPORTS_FOURBIT and load_in_4bit:
+        return FLOAT_TO_INT_MAPPER.get(model_name)
+
+    return None
 
-        new_model_name = MAP_TO_UNSLOTH_16bit[lower_model_name]
-        return new_model_name
 
-    elif load_in_4bit and SUPPORTS_FOURBIT and lower_model_name in FLOAT_TO_INT_MAPPER:
+def _get_new_mapper():
+    """
+    Fetches updated mappings from the Unsloth repository.
 
-        # Support returning original full -bnb-4bit name if specified specifically
-        # since we'll map it to the dynamic version instead
-        if lower_model_name.endswith("-bnb-4bit"):
-            return lower_model_name
+    Returns:
+        tuple: Updated INT_TO_FLOAT_MAPPER, FLOAT_TO_INT_MAPPER, MAP_TO_UNSLOTH_16bit
+    """
+    new_mapper_url = "https://raw.githubusercontent.com/unslothai/unsloth/main/unsloth/models/mapper.py"
+
+    try:
+        response = requests.get(new_mapper_url, timeout=3)
+        response.raise_for_status()
 
-        new_model_name = FLOAT_TO_INT_MAPPER[lower_model_name]
-        # logger.warning_once(
-        #     f"Unsloth: You passed in `{model_name}` and `load_in_4bit = True`.\n"\
-        #     f"We shall load `{new_model_name}` for 4x faster loading."
-        # )
-        return new_model_name
-    pass
+        # Extract dictionary mappings from the fetched script
+        exec_globals = {}
+        exec(response.text, exec_globals)
+
+        return (
+            exec_globals.get("INT_TO_FLOAT_MAPPER", INT_TO_FLOAT_MAPPER),
+            exec_globals.get("FLOAT_TO_INT_MAPPER", FLOAT_TO_INT_MAPPER),
+            exec_globals.get("MAP_TO_UNSLOTH_16bit", MAP_TO_UNSLOTH_16bit)
+        )
+    except Exception as e:
+        print(f"Warning: Failed to fetch updated Unsloth mappers. Using existing mappings. Error: {e}")
+        return INT_TO_FLOAT_MAPPER, FLOAT_TO_INT_MAPPER, MAP_TO_UNSLOTH_16bit
 
-    return None
-pass
 
+def get_model_name(model_name, load_in_4bit=True):
+    """
+    Retrieves the correct model name, ensuring compatibility with Unsloth and 4-bit loading.
 
-def _get_new_mapper():
-    try:
-        import requests
-        new_mapper = "https://raw.githubusercontent.com/unslothai/unsloth/main/unsloth/models/mapper.py"
-        with requests.get(new_mapper, timeout = 3) as new_mapper: new_mapper = new_mapper.text
-        new_mapper = new_mapper[new_mapper.find("__INT_TO_FLOAT_MAPPER"):]
-        new_mapper = new_mapper\
-            .replace("INT_TO_FLOAT_MAPPER",  "NEW_INT_TO_FLOAT_MAPPER")\
-            .replace("FLOAT_TO_INT_MAPPER",  "NEW_FLOAT_TO_INT_MAPPER")\
-            .replace("MAP_TO_UNSLOTH_16bit", "NEW_MAP_TO_UNSLOTH_16bit")
-
-        exec(new_mapper, globals())
-        return NEW_INT_TO_FLOAT_MAPPER, NEW_FLOAT_TO_INT_MAPPER, NEW_MAP_TO_UNSLOTH_16bit
-    except:
-        return {}, {}, {}
-    pass
-pass
-
-
-def get_model_name(model_name, load_in_4bit = True):
+    Args:
+        model_name (str): The base model name (e.g., "mistral-7b").
+        load_in_4bit (bool): Whether to load in 4-bit precision.
+
+    Returns:
+        str: The mapped model name.
+    """
     new_model_name = __get_model_name(
-        model_name = model_name,
-        load_in_4bit = load_in_4bit,
-        INT_TO_FLOAT_MAPPER  = INT_TO_FLOAT_MAPPER,
-        FLOAT_TO_INT_MAPPER  = FLOAT_TO_INT_MAPPER,
-        MAP_TO_UNSLOTH_16bit = MAP_TO_UNSLOTH_16bit,
+        model_name,
+        load_in_4bit,
+        INT_TO_FLOAT_MAPPER,
+        FLOAT_TO_INT_MAPPER,
+        MAP_TO_UNSLOTH_16bit,
     )
-    if new_model_name is None and model_name.count("/") == 1 and model_name[0].isalnum():
-        # Try checking if a new Unsloth version allows it!
-        NEW_INT_TO_FLOAT_MAPPER, NEW_FLOAT_TO_INT_MAPPER, NEW_MAP_TO_UNSLOTH_16bit = _get_new_mapper()
-        upgraded_model_name = __get_model_name(
-            model_name = model_name,
-            load_in_4bit = load_in_4bit,
-            INT_TO_FLOAT_MAPPER  = NEW_INT_TO_FLOAT_MAPPER,
-            FLOAT_TO_INT_MAPPER  = NEW_FLOAT_TO_INT_MAPPER,
-            MAP_TO_UNSLOTH_16bit = NEW_MAP_TO_UNSLOTH_16bit,
-        )
-        if upgraded_model_name is not None:
+
+    if new_model_name:
+        return new_model_name
+
+    if "/" in model_name and model_name[0].isalnum():
+        # Fetch latest Unsloth mappings if model is not recognized
+        updated_mappers = _get_new_mapper()
+        new_model_name = __get_model_name(model_name, load_in_4bit, *updated_mappers)
+
+        if new_model_name:
             raise NotImplementedError(
-                f"Unsloth: {model_name} is not supported in your current Unsloth version! Please update Unsloth via:\n\n"\
-                'pip uninstall unsloth unsloth_zoo -y\n'\
-                'pip install --upgrade --no-cache-dir "unsloth[colab-new] @ git+https://github.com/unslothai/unsloth.git"\n'\
-                'pip install --upgrade --no-cache-dir "git+https://github.com/unslothai/unsloth-zoo.git"\n'\
+                f"Unsloth: {model_name} is not supported in your current Unsloth version!\n"
+                "Please update Unsloth via:\n\n"
+                'pip uninstall unsloth unsloth_zoo -y\n'
+                'pip install --upgrade --no-cache-dir "unsloth[colab-new] @ git+https://github.com/unslothai/unsloth.git"\n'
+                'pip install --upgrade --no-cache-dir "git+https://github.com/unslothai/unsloth-zoo.git"\n'
             )
-        pass
-    pass
-    return new_model_name if new_model_name is not None else model_name
-pass
+
+    return model_name