make proc_val more permissive: not run when type differs from recording

Author: DanielYang59

src/pymatgen/io/vasp/inputs.py

@@ -1039,7 +1039,8 @@ def smart_int_or_float_bool(str_: str) -> float | int | bool:
             if "int" in incar_types:
                 return int(re.match(r"^-?[0-9]+", val)[0])  # type: ignore[index]
 
-        except ValueError:
+        # If re.match doesn't hit, it would return None and thus TypeError from indexing
+        except (ValueError, TypeError):
             pass
 
         # Not in known keys. We will try a hierarchy of conversions.

tests/io/vasp/test_inputs.py

@@ -1013,6 +1013,43 @@ def test_proc_val(self):
         assert Incar.proc_val("LREAL", "Auto") == "Auto"
         assert Incar.proc_val("LREAL", "on") == "On"
 
+    def test_proc_val_inconsistent_type(self):
+        """proc_val should not raise even when value conflicts with expected type."""
+
+        bool_values = ["T", ".FALSE."]
+        int_values = ["5", "-3"]
+        float_values = ["1.23", "-4.56e-2"]
+        list_values = ["3*1.0 2*0.5", "1 2 3"]
+        str_values = ["Auto", "Run", "Hello"]
+
+        # Expect bool
+        for v in int_values + float_values + list_values + str_values:
+            assert Incar.proc_val("LASPH", v) is not None
+
+        # Expect int
+        for v in bool_values + float_values + list_values + str_values:
+            assert Incar.proc_val("LORBIT", v) is not None
+
+        # Expect float
+        for v in bool_values + int_values + list_values + str_values:
+            assert Incar.proc_val("ENCUT", v) is not None
+
+        # Expect str
+        for v in bool_values + int_values + float_values + list_values:
+            assert Incar.proc_val("ALGO", v) is not None
+
+        # Expect list
+        for v in bool_values + int_values + float_values + str_values:
+            assert Incar.proc_val("PHON_TLIST", v) is not None
+
+        # Union type (bool | str)
+        for v in int_values + float_values + list_values:
+            assert Incar.proc_val("LREAL", v) is not None
+
+        # Non-existent
+        for v in int_values + float_values + list_values + str_values + bool_values:
+            assert Incar.proc_val("HELLOWORLD", v) is not None
+
     def test_check_params(self):
         # Triggers warnings when running into invalid parameters
         incar = Incar(