Comment 10 for bug 1899193

### Issue 3: aptd file descriptor leak (GHSL-2020-170)

I also found out that if the function returns successfully, the runtime won't immediately deallocate the object once it's reference count reaches zero, so e.g.

def f():
    apt_inst.DebFile("../apt_1.9.5_amd64.deb")

f()

will cause an extra fd to be used, until the cyclic garbage collector ran. I think this is a problem I introduced years ago when I made them subclassable because that somehow required adding GC support or something - I don't remember.

In any case, this means, that these need to become context managers or at least gain a close() method so that they can be closed when no longer needed.

arfile_new has the same issue FWIW, if there's an error somewhere and the file was opened, it leaks it, as does tagfile_new; and both of them also have memory leaks as they never free those objects in these error cases.