guard against empty shape arrays by setting initial value in reduce operations over state dimensions in State

pydra/engine/state.py

@@ -1150,12 +1150,12 @@
         else:
             container_ndim = self.container_ndim_all.get(term, 1)
             shape = input_shape(self.inputs[term], container_ndim=container_ndim)
-            var_ind = range(reduce(lambda x, y: x * y, shape))
+            var_ind = range(reduce(lambda x, y: x * y, shape, 1))
             new_keys = [term]
             # checking if the term is in inner_inputs
             if term in self.inner_inputs:
                 # TODO: have to be changed if differ length
-                inner_len = [shape[-1]] * reduce(lambda x, y: x * y, shape[:-1])
+                inner_len = [shape[-1]] * reduce(lambda x, y: x * y, shape[:-1], 1)
                 # this come from the previous node
                 outer_ind = self.inner_inputs[term].ind_l
                 var_ind_out = itertools.chain.from_iterable(
@@ -1172,7 +1172,7 @@
             self.inputs[op_single],
             container_ndim=self.container_ndim_all.get(op_single, 1),
         )
-        val_ind = range(reduce(lambda x, y: x * y, shape))
+        val_ind = range(reduce(lambda x, y: x * y, shape, 1))
         if op_single in self.inner_inputs:
             # TODO: have to be changed if differ length
             inner_len = [shape[-1]] * reduce(lambda x, y: x * y, shape[:-1], 1)