Unable to edit schema after graph is created

[joshcho]

This issue deals with

vivace-graph-v3/schema.lisp

Lines 75 to 79 in cf2caaf

	(setf (schema-class-locks schema) nil)
	(setf (schema-lock schema) nil)
	(cl-store:store (schema graph) schema-file)
	(setf (schema-lock schema) schema-lock)
	(setf (schema-class-locks schema) locks)

and

vivace-graph-v3/graph.lisp

Lines 130 to 133 in cf2caaf

	(if (probe-file schema-file)
	(setf (schema graph)
	(cl-store:restore schema-file))
	(init-schema graph))

I noticed that after making the graph, its schema is stored without any of its class locks or locks. Then when it's restored, the class locks nor locks return, resulting in (schema-class-locks (schema graph)) being nil. This prevents some functions that use instantiate-node-type, e.g. def-edge.

To recreate, make an empty graph, close it, open it again, just to notice schema-class-locks being nil. Then you can't def-edge.

Temporarily I have made a workaround to this issue in my fork.