fix: handle legacy Lyria output accessors

google/genai/_interactions/_legacy_lyria.py

@@ -103,13 +103,22 @@
 }
 
 
+def _is_legacy_lyria_model(model: object) -> bool:
+    if not isinstance(model, str):
+        return False
+    return any(
+        model == known_model or model.endswith(f"/models/{known_model}")
+        for known_model in LEGACY_LYRIA_MODELS
+    )
+
+
 def is_legacy_lyria_request(*, is_vertex: bool, model: object) -> bool:
     """Return True iff the (client, model) combination needs the shim active.
 
     Used at request issue time (in the resource layer) to decide whether to
     pick the `LegacyLyriaInteractionStream` subclass for streaming requests.
     """
-    return bool(is_vertex) and isinstance(model, str) and model in LEGACY_LYRIA_MODELS
+    return bool(is_vertex) and _is_legacy_lyria_model(model)
 
 
 def is_legacy_lyria_response_body(data: object) -> bool:
@@ -125,7 +134,7 @@ def is_legacy_lyria_response_body(data: object) -> bool:
         return False
     typed_data: Dict[str, Any] = cast("Dict[str, Any]", data)
     model = typed_data.get("model")
-    return isinstance(model, str) and model in LEGACY_LYRIA_MODELS
+    return _is_legacy_lyria_model(model)
 
 
 def maybe_remap_legacy_sse_event(data: Dict[str, Any]) -> Dict[str, Any]:

google/genai/_interactions/types/interaction.py

@@ -430,7 +430,7 @@ def output_text(self) -> str:
     @property
     def output_image(self) -> Optional[ImageContent]:
         """The last image generated by the model in response to the current request."""
-        for step in reversed(self.steps):
+        for step in reversed(self.steps or []):
             if isinstance(step, UserInputStep):
                 break
             if isinstance(step, ModelOutputStep) and step.content:
@@ -442,7 +442,7 @@ def output_image(self) -> Optional[ImageContent]:
     @property
     def output_audio(self) -> Optional[AudioContent]:
         """The last audio generated by the model in response to the current request."""
-        for step in reversed(self.steps):
+        for step in reversed(self.steps or []):
             if isinstance(step, UserInputStep):
                 break
             if isinstance(step, ModelOutputStep) and step.content:
@@ -454,7 +454,7 @@ def output_audio(self) -> Optional[AudioContent]:
     @property
     def output_video(self) -> Optional[VideoContent]:
         """The last video generated by the model in response to the current request."""
-        for step in reversed(self.steps):
+        for step in reversed(self.steps or []):
             if isinstance(step, UserInputStep):
                 break
             if isinstance(step, ModelOutputStep) and step.content:

google/genai/tests/interactions/test_legacy_lyria.py

@@ -0,0 +1,68 @@
+# Copyright 2025 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+
+from ..._interactions._legacy_lyria import (
+    is_legacy_lyria_request,
+    is_legacy_lyria_response_body,
+)
+from ..._interactions.types.interaction import Interaction
+
+
+_LYRIA_MODEL_PATH = (
+    "projects/123/locations/global/publishers/google/models/lyria-3-clip-preview"
+)
+
+
+def test_legacy_lyria_vertex_model_path_rewrites_outputs_to_steps():
+    interaction = Interaction.model_validate(
+        {
+            "id": "interaction-1",
+            "created": "2026-01-01T00:00:00Z",
+            "updated": "2026-01-01T00:00:01Z",
+            "status": "completed",
+            "model": _LYRIA_MODEL_PATH,
+            "outputs": [
+                {
+                    "type": "audio",
+                    "data": "abc",
+                    "mime_type": "audio/wav",
+                }
+            ],
+        }
+    )
+
+    assert len(interaction.steps) == 1
+    assert interaction.output_audio is not None
+    assert interaction.output_audio.data == "abc"
+    assert interaction.model_extra is None or "outputs" not in interaction.model_extra
+
+
+def test_legacy_lyria_model_path_detection():
+    assert is_legacy_lyria_request(is_vertex=True, model=_LYRIA_MODEL_PATH)
+    assert is_legacy_lyria_response_body({"model": _LYRIA_MODEL_PATH})
+
+
+def test_output_accessors_tolerate_missing_steps():
+    interaction = Interaction.construct(
+        id="interaction-1",
+        created="2026-01-01T00:00:00Z",
+        updated="2026-01-01T00:00:01Z",
+        status="completed",
+        steps=None,
+    )
+
+    assert interaction.output_image is None
+    assert interaction.output_audio is None
+    assert interaction.output_video is None