[Misc][LoRA] Support loading LoRA weights for target_modules in reg f…

…ormat (vllm-project#9275)

tests/lora/conftest.py

@@ -199,6 +199,11 @@ def baichuan_zero_lora_files():
     return snapshot_download(repo_id="jeeejeee/baichuan7b-zero-init")
 
 
+@pytest.fixture(scope="session")
+def baichuan_regex_lora_files():
+    return snapshot_download(repo_id="jeeejeee/baichuan-7b-lora-zero-regex")
+
+
 @pytest.fixture(scope="session")
 def minicpmv_lora_files():
     return snapshot_download(repo_id="jeeejeee/minicpmv25-lora-pokemon")

tests/lora/test_lora_checkpoints.py

@@ -5,14 +5,17 @@
 from vllm.lora.models import LoRAModel
 from vllm.model_executor.models.baichuan import BaiChuanBaseForCausalLM
 
-lora_lst = ["baichuan7B", "baichuan7B-zero", "chatglm3-6b"]
+lora_lst = [
+    "baichuan7B", "baichuan7B-zero", "baichuan7B-zero-regex", "chatglm3-6b"
+]
 
 
 @pytest.mark.parametrize("lora_name", lora_lst)
 def test_load_checkpoints(
     lora_name,
     baichuan_lora_files,
     baichuan_zero_lora_files,
+    baichuan_regex_lora_files,
     chatglm3_lora_files,
 ):
     supported_lora_modules = BaiChuanBaseForCausalLM.supported_lora_modules
@@ -36,7 +39,7 @@ def test_load_checkpoints(
             embedding_modules=embedding_modules,
             embedding_padding_modules=embed_padding_modules)
     elif lora_name == "baichuan7B-zero":
-        #Test that the target_modules contain prefix
+        # Test that the target_modules contain prefix
         # such as "model.layers.0.self_atten.W_pack", and
         # the test should pass.
         LoRAModel.from_local_checkpoint(
@@ -46,6 +49,16 @@ def test_load_checkpoints(
             device="cpu",
             embedding_modules=embedding_modules,
             embedding_padding_modules=embed_padding_modules)
+    elif lora_name == "baichuan7B-zero-regex":
+        # Test that the `target_modules` in the form of regular expressions,
+        # such as `model\\..*(W_pack|o_proj)`, and the test should pass.
+        LoRAModel.from_local_checkpoint(
+            baichuan_regex_lora_files,
+            expected_lora_modules,
+            lora_model_id=1,
+            device="cpu",
+            embedding_modules=embedding_modules,
+            embedding_padding_modules=embed_padding_modules)
     else:
         # For the baichuan7B model, load chatglm3-6b's LoRA,
         # and the test should raise the following error.

vllm/lora/models.py

@@ -23,6 +23,7 @@
 from vllm.lora.lora import LoRALayerWeights, PackedLoRALayerWeights
 from vllm.lora.punica import PunicaWrapper
 from vllm.lora.utils import (from_layer, from_layer_logits_processor,
+                             is_regex_target_modules,
                              parse_fine_tuned_lora_name, replace_submodule)
 from vllm.model_executor.models import SupportsLoRA, supports_multimodal
 from vllm.model_executor.models.module_mapping import MultiModelKeys
@@ -233,6 +234,8 @@ def from_local_checkpoint(
             # modules.
             unexpected_modules = []
             target_modules = config["target_modules"]
+            if not isinstance(target_modules, list):
+                target_modules = [target_modules]
             for module in target_modules:
                 # Compatible with more modules,
                 # such as:layers.11.self_attn.k_proj
@@ -243,8 +246,8 @@ def from_local_checkpoint(
             # expected_lora_modules. It is not reliable. See
             # https://github.com/vllm-project/vllm/pull/5909. But there's no
             # other better mechanism.
-            if unexpected_modules:
-                print(unexpected_modules, "modules")
+            if unexpected_modules and not is_regex_target_modules(
+                    config["target_modules"], expected_lora_modules):
                 raise ValueError(
                     f"While loading {lora_dir}, expected"
                     f" target modules in {expected_lora_modules}"

vllm/lora/utils.py

@@ -1,5 +1,6 @@
 import os
-from typing import List, Optional, Set, Tuple, Type
+import re
+from typing import List, Optional, Set, Tuple, Type, Union
 
 import huggingface_hub
 from huggingface_hub.utils import (EntryNotFoundError, HfHubHTTPError,
@@ -113,6 +114,38 @@ def parse_fine_tuned_lora_name(name: str) -> Tuple[str, bool]:
     raise ValueError(f"{name} is unsupported LoRA weight")
 
 
+def is_regex_target_modules(load_modules: Union[str, List[str]],
+                            expected_lora_modules: List[str]) -> bool:
+    """
+    PEFT supports passing `target_modules` in the form of regular expressions, 
+    such as `model.*(q_proj|k_proj|v_proj)$`. This function is mainly used to 
+    determine whether the suffix in the regular expression is present in the 
+    `expected_lora_modules`.
+    """
+
+    def is_valid_regex(pattern):
+        try:
+            re.compile(pattern)
+            return True
+        except re.error:
+            return False
+
+    def is_subset(sub_list, full_list):
+        return set(sub_list).issubset(set(full_list))
+
+    # Similar to PEFT's processing logic, regex-related operations are only
+    #  executed when the load_modules is a `str`.
+    if not isinstance(load_modules, str):
+        return False
+
+    if is_valid_regex(load_modules):
+        match = re.search(r"\((.*?)\)\$?$", load_modules)
+        if match:
+            suffix = match.group(1).split("|")
+            return is_subset(suffix, expected_lora_modules)
+    return False
+
+
 def get_adapter_absolute_path(lora_path: str) -> str:
     """
     Resolves the given lora_path to an absolute local path.