fix: wrongly decorated _validate_inplane_pec validator

Author: yaugenst-flex

CHANGELOG.md

@@ -32,6 +32,7 @@ with fewer layers than recommended.
 - Fixed incorrect gradient computation in PyTorch plugin (`to_torch`) for functions returning multi-element arrays.
 - `MonitorData.get_amplitude()` no longers multiplies by a factor of `1j` and now directly returns the complex value of the data.
 - `EMESimulationData.port_modes_tuple` is now symmetry-expanded.
+- Fixed `Medium2D` validation error message when invalid data is passed to `ss`.
 
 ## [2.9.0rc1] - 2025-06-10
 

tidy3d/components/medium.py

@@ -7036,8 +7036,8 @@ def _validate_modulation_spec(cls, val):
             )
         return val
 
-    @skip_if_fields_missing(["ss"])
     @pd.validator("tt", always=True)
+    @skip_if_fields_missing(["ss"])
     def _validate_inplane_pec(cls, val, values):
         """ss/tt components must be both PEC or non-PEC."""
         if isinstance(val, PECMedium) != isinstance(values["ss"], PECMedium):

tidy3d/components/tcad/simulation/heat_charge.py

@@ -889,7 +889,6 @@ def estimate_charge_mesh_size(cls, values):
             )
         return values
 
-    @skip_if_fields_missing(["analysis_spec", "monitors", "structures", "size"])
     @pd.root_validator(skip_on_failure=True)
     def check_transient_heat(cls, values):
         """Make sure transient heat simulations can run."""