From 9c342449691e54efbb9b0f4e3bab9d4e4a8d3986 Mon Sep 17 00:00:00 2001
From: jlnav <jnavarro@anl.gov>
Date: Wed, 11 Mar 2026 12:21:01 -0500
Subject: [PATCH] adjusts to please mypy, add mypy to precommit

---
 .pre-commit-config.yaml   | 5 +++++
 libensemble/utils/misc.py | 8 ++++----
 pixi.lock                 | 2 +-
 3 files changed, 10 insertions(+), 5 deletions(-)

diff --git a/.pre-commit-config.yaml b/.pre-commit-config.yaml
index de927cff8..515439b2b 100644
--- a/.pre-commit-config.yaml
+++ b/.pre-commit-config.yaml
@@ -32,3 +32,8 @@ repos:
       additional_dependencies: [black==22.12.0]
       files: ^(.*\.py|.*\.rst)$
       args: [--line-length=120]
+
+- repo: https://github.com/pre-commit/mirrors-mypy
+  rev: v1.19.1
+  hooks:
+    - id: mypy
diff --git a/libensemble/utils/misc.py b/libensemble/utils/misc.py
index c4327dd02..6e3779910 100644
--- a/libensemble/utils/misc.py
+++ b/libensemble/utils/misc.py
@@ -4,7 +4,6 @@
 
 from itertools import chain, groupby
 from operator import itemgetter
-from typing import List
 
 import numpy as np
 import numpy.typing as npt
@@ -85,6 +84,7 @@ def _get_combinable_multidim_names(first: dict, new_dtype_names: list) -> list:
 
 def _decide_dtype(name: str, entry, size: int) -> tuple:
     """decide dtype of field, and size if needed"""
+    output_type: str | type  # str for numpy string type, type for python type
     if isinstance(entry, str):  # use numpy style for string type
         output_type = "U" + str(len(entry) + 1)
     else:
@@ -115,7 +115,7 @@ def _pack_field(input_dict: dict, field_names: list) -> tuple:
     return tuple(input_dict[name] for name in field_names) if len(field_names) > 1 else input_dict[field_names[0]]
 
 
-def list_dicts_to_np(list_dicts: list, dtype: list = None, mapping: dict = {}) -> npt.NDArray:
+def list_dicts_to_np(list_dicts: list, dtype: list | None = None, mapping: dict = {}) -> npt.NDArray:
     """Convert list of dicts to numpy structured array"""
     if list_dicts is None:
         return None
@@ -231,7 +231,7 @@ def map_numpy_array(array: npt.NDArray, mapping: dict = {}) -> npt.NDArray:
         return array
 
     # Create new dtype with mapped fields
-    new_fields = []
+    new_fields: list[tuple] = []
 
     # Track fields processed by mapping to avoid duplication
     mapped_source_fields = set()
@@ -275,7 +275,7 @@ def map_numpy_array(array: npt.NDArray, mapping: dict = {}) -> npt.NDArray:
     return mapped_array
 
 
-def np_to_list_dicts(array: npt.NDArray, mapping: dict = {}) -> List[dict]:
+def np_to_list_dicts(array: npt.NDArray, mapping: dict = {}) -> list[dict]:
     """Convert numpy structured array to list of dicts"""
     out = []
 
diff --git a/pixi.lock b/pixi.lock
index 7ecb5aabd..f93bbb6a2 100644
--- a/pixi.lock
+++ b/pixi.lock
@@ -1,3 +1,3 @@
 version https://git-lfs.github.com/spec/v1
-oid sha256:e6c850dcd99a7481c401b3f7be69d1519994aaad0416880955acd41f2603082d
+oid sha256:ce81e3ca628ccd7f7370c1e3aeb11e3f5eb4da0ad3d4c809acf22c91c1ff7159
 size 1156243