trac #32095: sorted is not inplace

Author: dcoudert

src/sage/graphs/base/boost_graph.pyx

@@ -2381,8 +2381,8 @@ cdef double diameter_DiFUB(BoostVecWeightedDiGraphU g_boost,
     # distances respectively.
     # Now order_1 and order_2 will contain order of vertices in which
     # further distance computations will be done.
-    sorted(order_1, reverse=True)
-    sorted(order_2, reverse=True)
+    order_1 = sorted(order_1, reverse=True)
+    order_2 = sorted(order_2, reverse=True)
 
     LB = max(LB, LB_1, LB_2)
     if LB == sys.float_info.max:

src/sage/graphs/digraph.py

@@ -2490,6 +2490,15 @@ def diameter(self, by_weight=False, algorithm=None, weight_function=None,
             Traceback (most recent call last):
             ...
             ValueError: diameter is not defined for the empty DiGraph
+
+        :trac:`32095` is fixed::
+
+            sage: set_random_seed(4)
+            sage: G = graphs.RandomGNP(40, 0.4).to_directed()
+            sage: G.diameter(algorithm='DiFUB', by_weight=False)
+            3
+            sage: G.diameter(algorithm='DiFUB', by_weight=True)
+            3.0
         """
         if not self.order():
             raise ValueError("diameter is not defined for the empty DiGraph")