fix: prepare_for_smd() missing return value causes CustomOrchestrator container h (6200)

sagemaker-serve/src/sagemaker/serve/model_server/multi_model_server/prepare.py

@@ -123,3 +123,5 @@ def prepare_for_mms(
     hash_value = compute_hash(buffer=buffer)
     with open(str(code_dir.joinpath("metadata.json")), "wb") as metadata:
         metadata.write(_MetaData(hash_value).to_json())
+
+    return hash_value

sagemaker-serve/src/sagemaker/serve/model_server/smd/prepare.py

@@ -68,3 +68,5 @@ def prepare_for_smd(
     hash_value = compute_hash(buffer=buffer)
     with open(str(code_dir.joinpath("metadata.json")), "wb") as metadata:
         metadata.write(_MetaData(hash_value).to_json())
+
+    return hash_value

sagemaker-serve/src/sagemaker/serve/model_server/tensorflow_serving/prepare.py

@@ -61,3 +61,5 @@ def prepare_for_tf_serving(
     hash_value = compute_hash(buffer=buffer)
     with open(str(code_dir.joinpath("metadata.json")), "wb") as metadata:
         metadata.write(_MetaData(hash_value).to_json())
+
+    return hash_value

sagemaker-serve/src/sagemaker/serve/model_server/torchserve/prepare.py

@@ -73,3 +73,5 @@ def prepare_for_torchserve(
     hash_value = compute_hash(buffer=buffer)
     with open(str(code_dir.joinpath("metadata.json")), "wb") as metadata:
         metadata.write(_MetaData(hash_value).to_json())
+
+    return hash_value

sagemaker-serve/tests/unit/model_server/test_smd_prepare.py

@@ -44,6 +44,7 @@ def test_prepare_for_smd_with_inference_spec(self, mock_copy, mock_capture, mock
             )
 
         mock_inference_spec.prepare.assert_called_once_with(str(model_path))
+        self.assertEqual(secret_key, "test-hash")
 
     @patch("os.rename")
     @patch("sagemaker.serve.model_server.smd.prepare.compute_hash")
@@ -76,6 +77,7 @@ def test_prepare_for_smd_with_custom_orchestrator(
 
         # Verify custom_execution_inference.py was copied and renamed
         mock_rename.assert_called_once()
+        self.assertEqual(secret_key, "test-hash")
 
     @patch("sagemaker.serve.model_server.smd.prepare.compute_hash")
     @patch("sagemaker.serve.model_server.smd.prepare.capture_dependencies")
@@ -115,6 +117,31 @@ def test_prepare_for_smd_invalid_dir(self):
             prepare_for_smd(model_path=str(file_path), shared_libs=[], dependencies={})
         self.assertIn("not a valid directory", str(context.exception))
 
+    @patch("sagemaker.serve.model_server.smd.prepare.capture_dependencies")
+    @patch("shutil.copy2")
+    def test_prepare_for_smd_returns_hash_value(self, mock_copy, mock_capture):
+        """Test prepare_for_smd returns a valid SHA-256 hash string."""
+        from sagemaker.serve.model_server.smd.prepare import prepare_for_smd
+
+        model_path = Path(self.temp_dir) / "model"
+        code_dir = model_path / "code"
+        code_dir.mkdir(parents=True)
+
+        # Create a real serve.pkl file
+        serve_pkl = code_dir / "serve.pkl"
+        serve_pkl.write_bytes(b"test pickle data")
+
+        result = prepare_for_smd(
+            model_path=str(model_path), shared_libs=[], dependencies={}
+        )
+
+        # Verify the return value is a valid 64-character hex string (SHA-256)
+        self.assertIsNotNone(result)
+        self.assertIsInstance(result, str)
+        self.assertEqual(len(result), 64)
+        # Verify it's a valid hex string
+        int(result, 16)
+
 
 if __name__ == "__main__":
     unittest.main()