https://github.com/networkx/networkx/commit/ea2c8db07e0047daa649d484c4cf68ec2d9035f7
typo: swap source and target

--- networkx/algorithms/shortest_paths/astar.py.orig	2019-04-11 14:52:34.000000000 -0600
+++ networkx/algorithms/shortest_paths/astar.py	2019-09-11 09:22:19.922448001 -0600
@@ -131,7 +131,7 @@ def astar_path(G, source, target, heuris
             enqueued[neighbor] = ncost, h
             push(queue, (ncost + h, next(c), neighbor, ncost, curnode))
 
-    raise nx.NetworkXNoPath("Node %s not reachable from %s" % (source, target))
+    raise nx.NetworkXNoPath("Node %s not reachable from %s" % (target, source))
 
 
 def astar_path_length(G, source, target, heuristic=None, weight='weight'):
--- networkx/algorithms/shortest_paths/weighted.py.orig	2019-04-11 14:52:34.000000000 -0600
+++ networkx/algorithms/shortest_paths/weighted.py	2019-09-11 09:22:46.694007187 -0600
@@ -1422,7 +1422,7 @@ def bellman_ford_path_length(G, source,
         return length[target]
     except KeyError:
         raise nx.NetworkXNoPath(
-            "node %s not reachable from %s" % (source, target))
+            "node %s not reachable from %s" % (target, source))
 
 
 def single_source_bellman_ford_path(G, source, weight='weight'):
@@ -1597,7 +1597,7 @@ def single_source_bellman_ford(G, source
     try:
         return (dist[target], paths[target])
     except KeyError:
-        msg = "Node %s not reachable from %s" % (source, target)
+        msg = "Node %s not reachable from %s" % (target, source)
         raise nx.NetworkXNoPath(msg)