If you do that, Hibernate Search will not reindex. Hibernate Search already knows how to reindex your fields; it’s complaining that it cannot find a path from Basclt0100TO back to Basclt0900TO in order to actually perform reindexing.
It should find that path, though, because you defined the mappedBy on your association. There is something in your setup that is preventing Hibernate Search from understanding the mapping. What it is, I don’t know, but I know it’s not part of what you showed. And you know it too, since you tried to put this code in a new project and the problem disappeared. So there’s something else.
Browsing through past topics, I found a coworker of yours also having mapping problems with these Basclt classes: Lazy initialization exception on mass indexing/intial indexing - #2 by yrodiere . So I suspect there’s something highly unusual in your application; you need to find what it is in order to solve the problem.