dummy version updater for base simulation

tests/test_components/test_eme.py

@@ -86,6 +86,17 @@ def make_eme_sim():
     return sim
 
 
+def test_sim_version_update(log_capture):
+    sim = make_eme_sim()
+    sim_dict = sim.dict()
+    sim_dict["version"] = "ancient_version"
+
+    with AssertLogLevel(log_capture, "WARNING"):
+        sim_new = td.EMESimulation.parse_obj(sim_dict)
+
+    assert sim_new.version == td.__version__
+
+
 def test_eme_grid():
     sim_geom = td.Box(size=(4, 4, 4), center=(0, 0, 0))
     axis = 2

tests/test_components/test_heat.py

@@ -552,6 +552,17 @@ def test_relative_min_dl_warning(log_capture):
         )
 
 
+def test_sim_version_update(log_capture):
+    heat_sim = make_heat_sim()
+    heat_sim_dict = heat_sim.dict()
+    heat_sim_dict["version"] = "ancient_version"
+
+    with AssertLogLevel(log_capture, "WARNING"):
+        heat_sim_new = td.HeatSimulation.parse_obj(heat_sim_dict)
+
+    assert heat_sim_new.version == td.__version__
+
+
 @pytest.mark.parametrize("zero_dim_axis", [None, 0, 2])
 def test_symmetry_expanded(zero_dim_axis):
     symmetry_center = [2, 0.5, 0]

tidy3d/components/base_sim/simulation.py

@@ -104,6 +104,18 @@ class AbstractSimulation(Box, ABC):
 
     """ Validating setup """
 
+    @pd.root_validator(pre=True)
+    def _update_simulation(cls, values):
+        """Update the simulation if it is an earlier version."""
+
+        # dummy upgrade of version number
+        # this should be overriden by each simulation class if needed
+        current_version = values.get("version")
+        if current_version != __version__ and current_version is not None:
+            log.warning(f"updating {cls.__name__} from {current_version} to {__version__}")
+            values["version"] = __version__
+        return values
+
     # make sure all names are unique
     _unique_monitor_names = assert_unique_names("monitors")
     _unique_structure_names = assert_unique_names("structures")