core.Lattice cast pbc to bool (possibly np.bool_) (#4356)

* cast to bool

* update test

Author: DanielYang59

src/pymatgen/core/lattice.py

@@ -11,7 +11,7 @@
 from collections import defaultdict
 from fractions import Fraction
 from functools import reduce
-from typing import TYPE_CHECKING, cast
+from typing import TYPE_CHECKING
 
 import numpy as np
 from monty.dev import deprecated
@@ -183,7 +183,7 @@ def pbc(self, pbc: PbcLike) -> None:
         if len(pbc) != 3 or any(item not in {True, False} for item in pbc):
             raise ValueError(f"pbc must be a tuple of three True/False values, got {pbc}")
 
-        self._pbc = cast("tuple[bool, bool, bool]", tuple(pbc))
+        self._pbc = tuple(bool(item) for item in pbc)
 
     @property
     def is_3d_periodic(self) -> bool:

tests/core/test_structure.py

@@ -964,7 +964,11 @@ def test_to_from_ase_atoms(self):
         assert isinstance(atoms, Atoms)
         assert len(atoms) == len(self.struct)
 
-        assert AseAtomsAdaptor.get_structure(atoms) == self.struct
+        structure = AseAtomsAdaptor.get_structure(atoms)
+        assert structure == self.struct
+
+        # Ensure PBC is `bool` type (not `np.bool_`) and JSON serializable
+        assert "pymatgen.core.structure" in structure.to(fmt="json")
 
         assert IStructure.from_ase_atoms(atoms) == self.struct
         assert type(IStructure.from_ase_atoms(atoms)) is IStructure