Improve errors for invalid constants

CHANGELOG.md

@@ -32,6 +32,7 @@
 - Skip unused functions in module code generation, improving performance.
 - Avoid reloading modules if their content does not change, improving performance.
 - `wp.Mesh.points` is now a property instead of a raw data member, its reference can be changed after the mesh is initialized.
+- Improve error message when invalid objects are referenced in a Warp kernel.
 
 ### Fixed
 

warp/codegen.py

@@ -1647,7 +1647,7 @@ def emit_Name(adj, node):
         if isinstance(obj, types.ModuleType):
             return obj
 
-        raise RuntimeError("Cannot reference a global variable from a kernel unless `wp.constant()` is being used")
+        raise TypeError(f"Invalid external reference type: {type(obj)}")
 
     @staticmethod
     def resolve_type_attribute(var_type: type, attr: str):

warp/tests/test_codegen.py

@@ -405,22 +405,22 @@ def kernel_3_fn(
 
     kernel = wp.Kernel(func=kernel_1_fn)
     with test.assertRaisesRegex(
-        RuntimeError,
-        r"Cannot reference a global variable from a kernel unless `wp.constant\(\)` is being used",
+        TypeError,
+        r"Invalid external reference type: <class 'warp.types.array'>",
     ):
         wp.launch(kernel, dim=out.shape, inputs=(), outputs=(out,), device=device)
 
     kernel = wp.Kernel(func=kernel_2_fn)
     with test.assertRaisesRegex(
-        RuntimeError,
-        r"Cannot reference a global variable from a kernel unless `wp.constant\(\)` is being used",
+        TypeError,
+        r"Invalid external reference type: <class 'warp.types.array'>",
     ):
         wp.launch(kernel, dim=out.shape, inputs=(), outputs=(out,), device=device)
 
     kernel = wp.Kernel(func=kernel_3_fn)
     with test.assertRaisesRegex(
-        RuntimeError,
-        r"Cannot reference a global variable from a kernel unless `wp.constant\(\)` is being used",
+        TypeError,
+        r"Invalid external reference type: <class 'warp.types.array'>",
     ):
         wp.launch(kernel, dim=out.shape, inputs=(), outputs=(out,), device=device)
 

warp/tests/test_types.py

@@ -215,7 +215,7 @@ def test_constant(self):
         self.assertEqual(const, wp.vec3i(1, 2, 3))
 
     def test_constant_error_invalid_type(self):
-        with self.assertRaisesRegex(RuntimeError, r"Invalid constant type: <class 'tuple'>$"):
+        with self.assertRaisesRegex(TypeError, r"Invalid constant type: <class 'tuple'>$"):
             wp.constant((1, 2, 3))
 
     def test_vector_assign(self):

warp/types.py

@@ -66,8 +66,8 @@ def constant(x):
         x: Compile-time constant value, can be any of the built-in math types.
     """
 
-    if not isinstance(x, (builtins.bool, int, float, tuple(scalar_and_bool_types), ctypes.Array)):
-        raise RuntimeError(f"Invalid constant type: {type(x)}")
+    if not is_value(x):
+        raise TypeError(f"Invalid constant type: {type(x)}")
 
     return x
 
@@ -1384,7 +1384,7 @@ def type_is_matrix(t):
 
 # returns true for all value types (int, float, bool, scalars, vectors, matrices)
 def type_is_value(x):
-    return x in value_types or issubclass(x, ctypes.Array)
+    return x in value_types or hasattr(x, "_wp_scalar_type_")
 
 
 # equivalent of the above but for values