[CI][LoRA] Preserve QKV fuser split sizes through LoRA wrappers

tests/lora/test_layers.py

@@ -797,12 +797,18 @@ def create_column_parallel_packed_layer(idx: int = 0):
                 params_dtype=torch.float16,
                 prefix=f"layer_{idx}",
             )
+            linear.split_sizes = [
+                linear.num_heads * linear.head_size,
+                linear.num_kv_heads * linear.head_size,
+                linear.num_kv_heads * linear.v_head_size,
+            ]
             linear.weight.data = torch.rand_like(linear.weight.data)
             lora_linear = (
                 MergedQKVParallelLinearWithLoRA(linear)
                 if not fully_shard
                 else MergedQKVParallelLinearWithShardedLoRA(linear)
             )
+            assert lora_linear.split_sizes == linear.split_sizes
         else:
             linear = QKVParallelLinear(
                 4096,

vllm/lora/layers/column_parallel_linear.py

@@ -467,6 +467,17 @@ def __init__(self, base_layer: QKVParallelLinear) -> None:
             self.kv_shard_id,
             self.kv_shard_id,
         )
+        self.split_sizes = list(
+            getattr(
+                self.base_layer,
+                "split_sizes",
+                [
+                    self.q_proj_shard_size,
+                    self.kv_proj_shard_size,
+                    self.base_layer.num_kv_heads * self.base_layer.v_head_size,
+                ],
+            )
+        )
 
     def create_lora_weights(
         self,