Make Buildable fields instance variables.

packages/chassisml/src/chassis/builder/buildable.py

@@ -69,12 +69,13 @@ class Buildable(metaclass=abc.ABCMeta):
             [chassis.runtime.constants][].
     """
 
-    packaged = False
-    metadata = ModelMetadata.default()
-    requirements: set[str] = set()
-    apt_packages: set[str] = set()
-    additional_files: set[str] = set()
-    python_modules: dict = {}
+    def __init__(self):
+        self.packaged = False
+        self.metadata = ModelMetadata.default()
+        self.requirements: set[str] = set()
+        self.apt_packages: set[str] = set()
+        self.additional_files: set[str] = set()
+        self.python_modules: dict = {}
 
     def merge_package(self, package: Buildable):
         """

packages/chassisml/src/chassisml/v1/chassis_model.py

@@ -38,6 +38,7 @@ def __init__(self, process_fn: PredictFunction, batch_size: int = 1,
             legacy_predict_fn: For internal backwards-compatibility use only.
             chassis_client: For internal backwards-compatibility use only.
         """
+        super().__init__()
         self.runner = ModelRunner(process_fn, batch_size=batch_size,
                                   is_legacy_fn=legacy_predict_fn)
         self.python_modules[PYTHON_MODEL_KEY] = self.runner

packages/chassisml/tests/test_chassis_model.py

@@ -37,4 +37,22 @@ def test_adding_pip_requirements_from_conda_env(echo_predict_function):
     model.parse_conda_env(env)
     assert len(model.requirements.symmetric_difference(["scikit-learn", "numpy", "chassisml"])) == 0
 
+
+def test_each_model_instance_has_own_default_values(echo_predict_function):
+    model = ChassisModel(echo_predict_function)
+    assert model.metadata.model_name == ""
+    assert model.metadata.model_version == ""
+    assert model.metadata.has_inputs() is False
+    model.metadata.model_name = "Test Model"
+    model.metadata.model_version = "1.0.1"
+    model.metadata.add_input("input", ["text/plain"])
+    assert model.metadata.model_name == "Test Model"
+    assert model.metadata.model_version == "1.0.1"
+    assert model.metadata.has_inputs() is True
+
+    model2 = ChassisModel(echo_predict_function)
+    assert model2.metadata.model_name == ""
+    assert model2.metadata.model_version == ""
+    assert model2.metadata.has_inputs() is False
+
 # Verify that the fields in the metadata are updated based on the values provided during `prepare_context`.