Small string formatting bug in Graph.delete_vertex

[tjolivet]

If we remove a vertex which is a tuple from a graph which does not contain this vertex, Sage fails because it raises a TypeError instead of the usual RuntimeError: Vertex (1) not in the graph.

sage: G = Graph()
sage: G.delete_vertex((1,'a'))
---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)

/home/jaje/e_one_star/<ipython console> in <module>()

/home/jaje/sage-5.0.1/local/lib/python2.7/site-packages/sage/graphs/generic_graph.pyc in delete_vertex(self, vertex, in_order)
   7247             vertex = self.vertices()[vertex]
   7248         if vertex not in self:
-> 7249             raise RuntimeError("Vertex (%s) not in the graph."%vertex)
   7250 
   7251         attributes_to_update = ('_pos', '_assoc', '_embedding')

TypeError: not all arguments converted during string formatting

This is because the source code reads

raise RuntimeError("Vertex (%s) not in the graph."%vertex)

so it fails if vertex is a tuple (too many values to unpack for the %s), as illustrated here:

sage: "BLA%sBLA"%(1,'a')      
---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)

/home/jaje/e_one_star/<ipython console> in <module>()

TypeError: not all arguments converted during string formatting
sage: "BLA%sBLA"%str((1,'a'))
"BLA(1, 'a')BLA"

I guess this bug can just be corrected by replacing all the occurrences of %vertex by %str(vertex). It also occurs in DiGraph.delete_vertex.

[dcoudert]

This patch solves the problem for Graph and DiGraph? since the function is in generic_graph.py. The delete_vertices also add the same bug.

[tjolivet]

Thanks!

[dcoudert]

You are welcome.