[Bugfix] Fix missing lora name mapping for lora without prefix (#17793)

Signed-off-by: Isotr0py <2037008807@qq.com>

tests/lora/test_utils.py

 # SPDX-License-Identifier: Apache-2.0
 
 from collections import OrderedDict
+from typing import NamedTuple, Optional
 from unittest.mock import patch
 
 import pytest
@@ -9,52 +10,96 @@ from torch import nn
 
 from vllm.lora.utils import (get_adapter_absolute_path,
                              parse_fine_tuned_lora_name, replace_submodule)
+from vllm.model_executor.models.utils import WeightsMapper
+
+
+class LoRANameParserTestConfig(NamedTuple):
+    name: str
+    module_name: str
+    is_lora_a: bool
+    is_bias: bool
+    weights_mapper: Optional[WeightsMapper] = None
 
 
 def test_parse_fine_tuned_lora_name_valid():
-    fixture = {
-        ("base_model.model.lm_head.lora_A.weight", "lm_head", True, False),
-        ("base_model.model.lm_head.lora_B.weight", "lm_head", False, False),
-        (
+    fixture = [
+        LoRANameParserTestConfig("base_model.model.lm_head.lora_A.weight",
+                                 "lm_head", True, False),
+        LoRANameParserTestConfig("base_model.model.lm_head.lora_B.weight",
+                                 "lm_head", False, False),
+        LoRANameParserTestConfig(
             "base_model.model.model.embed_tokens.lora_embedding_A",
             "model.embed_tokens",
             True,
             False,
         ),
-        (
+        LoRANameParserTestConfig(
             "base_model.model.model.embed_tokens.lora_embedding_B",
             "model.embed_tokens",
             False,
             False,
         ),
-        (
+        LoRANameParserTestConfig(
             "base_model.model.model.layers.9.mlp.down_proj.lora_A.weight",
             "model.layers.9.mlp.down_proj",
             True,
             False,
         ),
-        (
+        LoRANameParserTestConfig(
             "base_model.model.model.layers.9.mlp.down_proj.lora_B.weight",
             "model.layers.9.mlp.down_proj",
             False,
             False,
         ),
-        (
+        LoRANameParserTestConfig(
             "language_model.layers.9.mlp.down_proj.lora_A.weight",
             "language_model.layers.9.mlp.down_proj",
             True,
             False,
         ),
-        (
+        LoRANameParserTestConfig(
             "language_model.layers.9.mlp.down_proj.lora_B.weight",
             "language_model.layers.9.mlp.down_proj",
             False,
             False,
         ),
-    }
-    for name, module_name, is_lora_a, is_bias in fixture:
+        # Test with WeightsMapper
+        LoRANameParserTestConfig(
+            "base_model.model.model.layers.9.mlp.down_proj.lora_A.weight",
+            "language_model.model.layers.9.mlp.down_proj",
+            True,
+            False,
+            weights_mapper=WeightsMapper(
+                orig_to_new_prefix={"model.": "language_model.model."}),
+        ),
+        LoRANameParserTestConfig(
+            "base_model.model.model.layers.9.mlp.down_proj.lora_B.weight",
+            "language_model.model.layers.9.mlp.down_proj",
+            False,
+            False,
+            weights_mapper=WeightsMapper(
+                orig_to_new_prefix={"model.": "language_model.model."}),
+        ),
+        LoRANameParserTestConfig(
+            "model.layers.9.mlp.down_proj.lora_A.weight",
+            "language_model.model.layers.9.mlp.down_proj",
+            True,
+            False,
+            weights_mapper=WeightsMapper(
+                orig_to_new_prefix={"model.": "language_model.model."}),
+        ),
+        LoRANameParserTestConfig(
+            "model.layers.9.mlp.down_proj.lora_B.weight",
+            "language_model.model.layers.9.mlp.down_proj",
+            False,
+            False,
+            weights_mapper=WeightsMapper(
+                orig_to_new_prefix={"model.": "language_model.model."}),
+        ),
+    ]
+    for name, module_name, is_lora_a, is_bias, weights_mapper in fixture:
         assert (module_name, is_lora_a,
-                is_bias) == parse_fine_tuned_lora_name(name)
+                is_bias) == parse_fine_tuned_lora_name(name, weights_mapper)
 
 
 def test_parse_fine_tuned_lora_name_invalid():

vllm/lora/utils.py

@@ -117,16 +117,18 @@ def parse_fine_tuned_lora_name(
     # LoRA weight qualified name usually starts with `base_model.model.`,
     # so we remove the prefix `base_model.model.` to make the following
     # mapping correctly.
-    if "base_model.model." in name:
+    if name.startswith("base_model.model."):
         name = name.replace("base_model.model.", "")
         name = weights_mapper._map_name(name) if weights_mapper else name
         # recover the prefix `base_model.model.`
         name = "base_model.model." + name
+    else:
+        name = weights_mapper._map_name(name) if weights_mapper else name
 
     # In some situations, we may not start with `base_model.model.`.
     # If we don't (e.g., ibm-granite/granite-speech-3.3-8b),
     # we should keep the prefix intact.
-    start_index = 2 if "base_model.model." in name else 0
+    start_index = 2 if name.startswith("base_model.model.") else 0
 
     parts = name.split(".")
     if parts[-1] == "weight" and (parts[-2] == "lora_A"