[Fix] don't force hybrid-SWA when sliding_window is disabled (#28604)

python/sglang/srt/configs/laguna.py

@@ -137,10 +137,7 @@ class LagunaConfig(PretrainedConfig):
         self.layer_types = (
             list(layer_types)
             if layer_types
-            else [
-                "full_attention" if i % 4 == 0 else "sliding_attention"
-                for i in range(num_hidden_layers)
-            ]
+            else ["full_attention" for _ in range(num_hidden_layers)]
         )
         self.mlp_layer_types = (
             list(mlp_layer_types)

python/sglang/srt/configs/model_config.py

@@ -1724,6 +1724,13 @@ def is_hybrid_swa_model(
         "LagunaForCausalLM",
     }
     if any(arch in hybrid_swa_archs for arch in model_architectures):
+        # Only treat Laguna as hybrid SWA when it actually has a sliding window.
+        if (
+            "LagunaForCausalLM" in model_architectures
+            and hf_text_config is not None
+            and not getattr(hf_text_config, "sliding_window", 0)
+        ):
+            return False
         return True
     # Also recognize models that explicitly opt-in via their HF text config,
     # so custom hybrid-SWA architectures don't need to be added to the allowlist.