Thank you for the PR! Do you have an idea how this could be tested?

This would reproduce it. I am not sure how to integrate into the test framework; since this is an igored exception in__del__.

from tinydb import TinyDBfrom tinydb import wherefrom tinydb.storages import JSONStoragefrom tinydb.middlewares import CachingMiddlewareclass DB(TinyDB):    def __init__(self, filename):        TinyDB.__init__(self, filename, storage=CachingMiddleware(JSONStorage))        self.foo = filenamedef main():    with DB("abcd.json") as db:        for i in range(12):            db.remove(where("key") == i)            d = {'key':i,                 'value':"1231",                }            db.insert(d)main()

Hmmm... The ignored exception is raised when garbage collecting the database object while the file handle has already been closed. It appears to me that on garbage collection the file handle is collected (and closed) first, followed by the storage/middleware. But this of course depends on the Python implementation and maybe even version¹, so I'll merge this PR without an accompanying test.

¹ I've tried to reliably force garbage collection of the database object, but haven't succeeded so far.

I've now released v2.3.2 which contains your changes 😃

Thanks!