let env vars override .pmgrc.yaml in _load_pmg_settings()

pymatgen/core/__init__.py

@@ -6,6 +6,8 @@
 operations on them.
 """
 
+from __future__ import annotations
+
 import os
 import warnings
 
@@ -29,28 +31,28 @@
 SETTINGS_FILE = os.path.join(os.path.expanduser("~"), ".pmgrc.yaml")
 
 
-def _load_pmg_settings():
-    # Load environment variables by default as backup
-    d = {}
-    for k, v in os.environ.items():
-        if k.startswith("PMG_"):
-            d[k] = v
-        elif k in ["VASP_PSP_DIR", "MAPI_KEY", "DEFAULT_FUNCTIONAL"]:
-            d["PMG_" + k] = v
-
-    # Override anything in env vars with that in yml file
+def _load_pmg_settings() -> dict[str, str]:
+    settings = {}
+    # Load .pmgrc.yaml file
     if os.path.exists(SETTINGS_FILE):
         try:
             yaml = YAML()
             with open(SETTINGS_FILE) as f:
                 d_yml = yaml.load(f)
-            d.update(d_yml)
+            settings.update(d_yml)
         except Exception as ex:
             # If there are any errors, default to using environment variables
             # if present.
             warnings.warn(f"Error loading .pmgrc.yaml: {ex}. You may need to reconfigure your yaml file.")
 
-    return d
+    # Override .pmgrc.yaml with env vars if present
+    for k, v in os.environ.items():
+        if k.startswith("PMG_"):
+            settings[k] = v
+        elif k in ["VASP_PSP_DIR", "MAPI_KEY", "DEFAULT_FUNCTIONAL"]:
+            settings["PMG_" + k] = v
+
+    return settings
 
 
 SETTINGS = _load_pmg_settings()

pymatgen/io/vasp/inputs.py

@@ -470,7 +470,6 @@ def get_string(self, direct: bool = True, vasp4_compatible: bool = False, signif
         Returns:
             String representation of POSCAR.
         """
-
         # This corrects for VASP really annoying bug of crashing on lattices
         # which have triple product < 0. We will just invert the lattice
         # vectors.
@@ -1244,12 +1243,9 @@ def automatic_gamma_density(structure: Structure, kppa: float):
             reciprocal lattice vector proportional to its length.
 
         Args:
-            structure:
-                Input structure
-            kppa:
-                Grid density
+            structure: Input structure
+            kppa: Grid density
         """
-
         latt = structure.lattice
         lengths = latt.abc
         ngrid = kppa / structure.num_sites
@@ -1889,8 +1885,8 @@ def from_symbol_and_functional(symbol: str, functional: str = None):
         :param functional: E.g., PBE
         :return: PotcarSingle
         """
-        if functional is None:
-            functional = SETTINGS.get("PMG_DEFAULT_FUNCTIONAL", "PBE")
+        functional = functional or SETTINGS.get("PMG_DEFAULT_FUNCTIONAL", "PBE")
+        assert isinstance(functional, str)  # type narrowing
         funcdir = PotcarSingle.functional_dir[functional]
         d = SETTINGS.get("PMG_VASP_PSP_DIR")
         if d is None:
@@ -2158,7 +2154,6 @@ def __getattr__(self, a):
         For float type properties, they are converted to the correct float. By
         default, all energies in eV and all length scales are in Angstroms.
         """
-
         try:
             return self.keywords[a.upper()]
         except Exception:
@@ -2420,7 +2415,9 @@ def run_vasp(
         :param err_file: File to write err.
         """
         self.write_input(output_dir=run_dir)
-        vasp_cmd = vasp_cmd or SETTINGS.get("PMG_VASP_EXE")
+        vasp_cmd = vasp_cmd or SETTINGS.get("PMG_VASP_EXE")  # type: ignore[assignment]
+        if not vasp_cmd:
+            raise ValueError("No VASP executable specified!")
         vasp_cmd = [os.path.expanduser(os.path.expandvars(t)) for t in vasp_cmd]
         if not vasp_cmd:
             raise RuntimeError("You need to supply vasp_cmd or set the PMG_VASP_EXE in .pmgrc.yaml to run VASP.")