fix(rl): accept numpy ints and reject bool in is_positive_integer

tests/rl/rl_utils_test.py

@@ -254,5 +254,52 @@ def _create_mock_train_example(
       np.testing.assert_array_equal(pack2.completion_mask, expected_mask_2)
 
 
+class IsPositiveIntegerTest(absltest.TestCase):
+  """Tests for `utils.is_positive_integer`."""
+
+  def test_accepts_python_int(self):
+    utils.is_positive_integer(1, 'x')
+    utils.is_positive_integer(100, 'x')
+
+  def test_accepts_numpy_int(self):
+    utils.is_positive_integer(np.int32(5), 'x')
+    utils.is_positive_integer(np.int64(5), 'x')
+    utils.is_positive_integer(np.uint8(5), 'x')
+
+  def test_accepts_none(self):
+    utils.is_positive_integer(None, 'x')
+
+  def test_rejects_zero(self):
+    with self.assertRaises(ValueError):
+      utils.is_positive_integer(0, 'x')
+
+  def test_rejects_negative(self):
+    with self.assertRaises(ValueError):
+      utils.is_positive_integer(-1, 'x')
+    with self.assertRaises(ValueError):
+      utils.is_positive_integer(np.int64(-5), 'x')
+
+  def test_rejects_bool(self):
+    with self.assertRaises(ValueError):
+      utils.is_positive_integer(True, 'x')
+    with self.assertRaises(ValueError):
+      utils.is_positive_integer(False, 'x')
+
+  def test_rejects_float(self):
+    with self.assertRaises(ValueError):
+      utils.is_positive_integer(1.0, 'x')
+    with self.assertRaises(ValueError):
+      utils.is_positive_integer(1.5, 'x')
+
+  def test_rejects_string(self):
+    with self.assertRaises(ValueError):
+      utils.is_positive_integer('5', 'x')
+
+  def test_error_message_includes_name(self):
+    with self.assertRaises(ValueError) as ctx:
+      utils.is_positive_integer(-1, 'max_steps')
+    self.assertIn('max_steps', str(ctx.exception))
+
+
 if __name__ == '__main__':
   absltest.main()

tunix/rl/utils.py

@@ -41,8 +41,17 @@
 
 
 def is_positive_integer(value: int | None, name: str):
-  """Checks if the value is positive."""
-  if value is not None and (not isinstance(value, int) or value <= 0):
+  """Checks if the value is a positive integer.
+
+  Accepts Python ``int`` and numpy integer scalars (e.g. ``np.int64``).
+  Explicitly rejects ``bool``, which is a subclass of ``int`` in Python but
+  is not semantically an integer in this context.
+  """
+  if value is None:
+    return
+  if isinstance(value, bool) or not isinstance(value, (int, np.integer)):
+    raise ValueError(f"{name} must be a positive integer. Got: {value}")
+  if value <= 0:
     raise ValueError(f"{name} must be a positive integer. Got: {value}")