Fix/validate positive float

CHANGELOG.md

@@ -5,6 +5,26 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [0.2.23] - 2026-09-14
+
+### Fixed
+- **`ValidationMixin.validate_positive_float` accepted `NaN` and `inf`.** The
+  check was `if value < 0`, which both slip past (`nan < 0` is False), so a
+  non-finite value passed validation and was committed to whatever property was
+  being set — poisoning every quantity derived from it with no exception
+  anywhere. Non-finite values now raise `ValueError`. Downstream: any setter
+  that reads a cached float and scales it (e.g.
+  `_Electrode.reversible_areal_capacity` in `steer-opencell-design`) could
+  silently store `nan`.
+
+### Added
+- `validate_positive_float(value, name, strictly=False)` takes a `strictly`
+  flag, mirroring `validate_positive_int`. With `strictly=True` a value of 0.0
+  is rejected, which callers need when zero would brick the property being set
+  (a zeroed denominator that can never be scaled back up). The default stays
+  non-strict (`>= 0`) because many callers legitimately pass 0.0 — zero
+  insulation width, zero gap, zero electrolyte overfill.
+
 ## [0.2.22] - 2026-08-18
 
 ### Fixed

steer_core/Mixins/TypeChecker.py

@@ -135,20 +135,41 @@ def validate_datum(datum: np.ndarray) -> None:
             raise TypeError("All coordinates in datum must be numbers.")
 
     @staticmethod
-    def validate_positive_float(value: float, name: str) -> None:
+    def validate_positive_float(value: float, name: str, strictly: bool = False) -> None:
         """Validate that a value is a positive float.
 
         Args:
             value: The value to validate.
             name: The name of the parameter for error messages.
+            strictly: If True, value must be strictly positive (> 0). Defaults to
+                False (>= 0), because many callers legitimately pass 0.0 (zero
+                insulation width, zero gap, zero overfill). Mirrors
+                :meth:`validate_positive_int`, which defaults to strict because
+                its callers are counts.
 
         Raises:
-            ValueError: If the value is not a positive float.
+            TypeError: If the value is not a number.
+            ValueError: If the value is NaN or infinite, or does not meet the
+                positivity requirement.
+
+        Examples:
+            >>> ValidationMixin.validate_positive_float(5.0, 'width')                   # OK
+            >>> ValidationMixin.validate_positive_float(0.0, 'width')                   # OK (non-strict default)
+            >>> ValidationMixin.validate_positive_float(0.0, 'width', strictly=True)    # ValueError
+            >>> ValidationMixin.validate_positive_float(-1.0, 'width')                  # ValueError
+            >>> ValidationMixin.validate_positive_float(float('nan'), 'width')          # ValueError
+            >>> ValidationMixin.validate_positive_float(float('inf'), 'width')          # ValueError
         """
         if not isinstance(value, (int, float, np.int64, np.float64)):
             raise TypeError(f"{name} must be a number. Provided: {type(value).__name__}.")
-        if value < 0:
-            raise ValueError(f"{name} must be a positive float. Provided: {value}.")
+        if not np.isfinite(value):
+            raise ValueError(f"{name} must be a finite number. Provided: {value}.")
+        if strictly:
+            if value <= 0:
+                raise ValueError(f"{name} must be a strictly positive float (> 0). Provided: {value}.")
+        else:
+            if value < 0:
+                raise ValueError(f"{name} must be a positive float. Provided: {value}.")
 
     @staticmethod
     def validate_positive_int(value: int, name: str, strictly: bool = True) -> None:

steer_core/__init__.py

@@ -1,7 +1,7 @@
 # SPDX-FileCopyrightText: 2024-2026 Stanford University
 # SPDX-License-Identifier: AGPL-3.0-or-later
 
-__version__ = "0.2.22"
+__version__ = "0.2.23"
 
 from .Mixins.Colors import ColorMixin
 from .Mixins.Coordinates import CoordinateMixin

test/test_typechecker_mixin.py

@@ -124,6 +124,29 @@ def test_non_numeric_raises(self):
     def test_numpy_int64(self):
         ValidationMixin.validate_positive_float(np.int64(5), "val")
 
+    def test_nan_raises(self):
+        with pytest.raises(ValueError):
+            ValidationMixin.validate_positive_float(float("nan"), "val")
+
+    def test_infinity_raises(self):
+        with pytest.raises(ValueError):
+            ValidationMixin.validate_positive_float(float("inf"), "val")
+
+    def test_negative_infinity_raises(self):
+        with pytest.raises(ValueError):
+            ValidationMixin.validate_positive_float(float("-inf"), "val")
+
+    def test_numpy_nan_raises(self):
+        with pytest.raises(ValueError):
+            ValidationMixin.validate_positive_float(np.float64("nan"), "val")
+
+    def test_strictly_rejects_zero(self):
+        with pytest.raises(ValueError):
+            ValidationMixin.validate_positive_float(0.0, "val", strictly=True)
+
+    def test_strictly_accepts_positive(self):
+        ValidationMixin.validate_positive_float(5.0, "val", strictly=True)
+
 
 class TestValidatePositiveInt: