Function makeDependencyGraph

src/backend/parser/parse_cte.c:647–663

* Identify the cross-references of a list of WITH RECURSIVE items, * and sort into an order that has no forward references. */

 * and sort into an order that has no forward references.
 */
static void
makeDependencyGraph(CteState *cstate)
{
	int			i;

	for (i = 0; i < cstate->numitems; i++)
	{
		CommonTableExpr *cte = cstate->items[i].cte;

		cstate->curitem = i;
		cstate->innerwiths = NIL;
		makeDependencyGraphWalker((Node *) cte->ctequery, cstate);
		Assert(cstate->innerwiths == NIL);
	}

	TopologicalSort(cstate->pstate, cstate->items, cstate->numitems);
}

/*
 * Tree walker function to detect cross-references and self-references of the