FilteredAdapter should not dynamically change to ordinary Adapter

[ulanmurzatayev]

When creating a FilteredAdapter with MongooseAdapter.newFilteredAdapter(config.db) it is expected to stay as FilteredAdapter. However current behaviour is that it changes dynamically during execution

casbin-mongoose-adapter/src/adapter.js

Line 141 in 4a87b7a

this.setFiltered(false);

Now the problem is that when a filtered adapter is first created casbin internally calls loadPolicy(model)

casbin-mongoose-adapter/src/adapter.js

Line 126 in 4a87b7a

async loadPolicy (model) {

which switches it back to an ordinary adapter. Then if a user calls enforcer.loadFilteredPolicy() casbin throws an error, as it does not recognize the adapter to be filtered anymore
https://github.com/casbin/node-casbin/blob/40dd90a6dd7a023746bc3c15593d96d802c612ab/src/coreEnforcer.ts#L164

I think loadPolicy() should work without changing the adapter type.

[ghaiklor]

Strange, but MongoDB adapter for casbin allows to change it in runtime - https://github.com/casbin/mongodb-adapter/blob/master/adapter.go#L186-L190

Actually, these chunks of code you provided is a direct port from there.

[ulanmurzatayev]

well it could be that there is a bug in mongodb-adapter as well. @ghaiklor do you agree that this should not happen?

[ghaiklor]

after some investigation into internals - agreed.

we should set the filtered flag to true only when calling from newFilteredAdapter and do not change it in runtime.

If the adapter was created as filtered one, it should stay that way and otherwise.