Dont allow on_collision(None, 1). Better assert for non-inf mass.

Author: viblo

CHANGELOG.rst

@@ -94,6 +94,7 @@ Other improvements:
   GCed.
 - Improved documentation in many places (``Vec2d``, ``Poly``, ``Shape`` and 
   more)
+- Improved assert for ``body.mass`` sanity check.
 - Internal cleanup of code
 
 

Munk2D

@@ -8,7 +8,7 @@
 b = pymunk.Body(1,10)
 c = pymunk.Circle(b, 5)
 s.add(b, c)
-h = s.add_collision_handler(None, None)
+h = s.on_collision(None, None)
 def f(arb, s, data):
     return False
 h.pre_solve = f

benchmarks/pymunk-collision-callback.py

@@ -252,8 +252,8 @@ def mass(self) -> float:
 
     @mass.setter
     def mass(self, mass: float) -> None:
-        assert (
-            self.space is None or mass > 0
+        assert self.space is None or 0 < mass < float(
+            "inf"
         ), "Dynamic bodies must have mass > 0 if they are attached to a Space."
         lib.cpBodySetMass(self._body, mass)
 

pymunk/body.py

@@ -605,7 +605,8 @@ def on_collision(
         normally.
 
         Its possible to pass in None for one or both of the collision types.
-        None matches any collision type on a Shape.
+        None matches any collision type on a Shape. However, if
+        collision_type_a is None, then collision_type_b must also be None.
 
         If you call this multiple times with the same combination of
         collision_type_a and collision_type_b, then the last call will
@@ -642,8 +643,9 @@ def on_collision(
         # key = min(collision_type_a, collision_type_b), max(
         #     collision_type_a, collision_type_b
         # )
-        if collision_type_a == None and collision_type_b != None:
-            collision_type_b, collision_type_a = collision_type_a, collision_type_b
+        assert (
+            collision_type_a != None or collision_type_b == None
+        ), "collision_type_a can not be None if collision_type_b is not None. Please swap them."
 
         key = collision_type_a, collision_type_b
         if key not in self._handlers:

pymunk/space.py

@@ -181,6 +181,9 @@ def test_mass(self) -> None:
         with self.assertRaises(AssertionError):
             b.mass = 0
 
+        with self.assertRaises(AssertionError):
+            b.mass = float("inf")
+
         s.remove(b)
         b.mass = 0
         s.add(b)

pymunk/tests/test_body.py

@@ -914,7 +914,8 @@ def pre_solve(arb: p.Arbiter, space: p.Space, data: Any) -> None:
             d["space"] = space  # type: ignore
 
         s.on_collision(1, None, pre_solve=pre_solve)
-        s.on_collision(None, 1, pre_solve=pre_solve)
+        with self.assertRaises(AssertionError):
+            s.on_collision(None, 1, pre_solve=pre_solve)
 
         s.step(0.1)