BUG: accept numpy integer parachute height triggers (#1106)

rocketpy/rocket/parachute.py

@@ -1,4 +1,5 @@
 from inspect import Parameter, signature
+from numbers import Real
 
 import numpy as np
 
@@ -350,8 +351,8 @@ def wrapper(p, h, y, sensors, u_dot):
             self.triggerfunc = _make_wrapper(trigger)
             return
 
-        # Numeric altitude trigger
-        if isinstance(trigger, (int, float)):
+        # Numeric altitude trigger (accept numpy integers/floats; reject bool)
+        if isinstance(trigger, Real) and not isinstance(trigger, bool):
             self._trigger_falling_only = True
 
             def triggerfunc(p, h, y, sensors, u_dot):  # pylint: disable=unused-argument
@@ -379,8 +380,8 @@ def triggerfunc(p, h, y, sensors, u_dot):  # pylint: disable=unused-argument
         # If we reach this point, the trigger is invalid
         raise ValueError(
             f"Unable to set the trigger function for parachute '{self.name}'. "
-            + "Trigger must be a callable, a float value or one of the strings "
-            + "('apogee'). "
+            + "Trigger must be a callable, a real number (height in meters), "
+            + "or one of the strings ('apogee'). "
             + "See the Parachute class documentation for more information."
         )
 

tests/unit/rocket/test_parachute.py

@@ -130,3 +130,32 @@ def test_callable_trigger_arities_route_arguments(trigger, expects_udot):
     result = parachute.triggerfunc(800.0, 500.0, [0.0] * 6, [], [1.0] * 6)
     assert result is True
     assert parachute.triggerfunc._expects_udot is expects_udot
+
+
+class TestParachuteNumericTrigger:
+    """Numeric height triggers must accept numpy scalar integers/floats and
+    reject bool (which is a Real subclass in Python)."""
+
+    @pytest.mark.parametrize(
+        "trigger",
+        [
+            800,
+            800.0,
+            np.int32(800),
+            np.int64(800),
+            np.float64(800.0),
+        ],
+    )
+    def test_numeric_height_trigger_accepted(self, trigger):
+        parachute = _make_parachute(trigger=trigger)
+        assert callable(parachute.triggerfunc)
+        # Falling below trigger height should fire
+        y = np.zeros(13)
+        y[5] = -1.0
+        assert bool(parachute.triggerfunc(101325.0, 799.0, y, [], None)) is True
+        assert bool(parachute.triggerfunc(101325.0, 801.0, y, [], None)) is False
+
+    @pytest.mark.parametrize("trigger", [True, False])
+    def test_bool_trigger_rejected(self, trigger):
+        with pytest.raises(ValueError, match="real number"):
+            _make_parachute(trigger=trigger)