[ModelOpt] Fix Weight Loading for DSR1-FP4 Quantization (#9712)

Signed-off-by: Pavani Majety <pmajety@nvidia.com>

python/sglang/srt/layers/linear.py

@@ -235,8 +235,9 @@ class ReplicatedLinear(LinearBase):
                     loaded_weight = loaded_weight[:1]
                 else:
                     raise ValueError(f"{loaded_weight} are not all equal")
-
-        assert param.size() == loaded_weight.size()
+        assert (
+            param.size() == loaded_weight.size()
+        ), f"Loading weight error:  param: {param.size()}, loaded_weight: {loaded_weight.size()}"
         param.data.copy_(loaded_weight)
 
     def forward(self, x: torch.Tensor) -> Tuple[torch.Tensor, Optional[torch.Tensor]]:

python/sglang/srt/layers/quantization/modelopt_quant.py

@@ -599,6 +599,13 @@ class ModelOptFp4Config(QuantizationConfig):
             regex_str = pattern.replace(".", r"\.").replace("*", r".*")
             if re.fullmatch(regex_str, prefix):
                 return True
+
+            # Check if the last part of the excluded pattern is contained in the last part of the prefix
+            # This handles fused modules like fused_qkv_a_proj_with_mqa that contain q_a_proj and kv_a_proj_with_mqa
+            pattern_last_part = pattern.split(".")[-1]
+            prefix_last_part = prefix.split(".")[-1]
+            if pattern_last_part in prefix_last_part:
+                return True
         return False
 
     def get_quant_method(