This will no longer work in future releases of the jdk. Mockito is currently self-attaching to enable the inline-mock-maker. Perhaps pandas wants me to do this explicitly, but i dont see how i could downcast a string to a numerical type before the replacement happens. 路 i get this warning while testing in spring boot: Im wondering how this break in backwards compatibility should in general be navigated. 路 the future statement is intended to ease migration to future versions of python that introduce incompatible changes to the language. It allows use of the new features on a per-module basis before the release in which the feature becomes standard. 路 in this case it does work. In general, it probably doesnt. Please add mockito as an 路 the class template std::future provides a mechanism to access the result of asynchronous operations: Perhaps installing a previous version of cmake is the only way that always works? 路 to opt-in to the future behavior, set pd. set_option(future. no_silent_downcasting, true) 0 1 1 0 2 2 3 1 dtype: That would mean that each project in the future should specify the cmake version on which it should be built. The creator of the asynchronous operation can then use a variety of methods to query, wait for, or extract a value from the std. An asynchronous operation (created via std::async, std::packaged_task, or std::promise) can provide a std::future object to the creator of that asynchronous operation. Int64 if i understand the warning correctly, the object dtype is downcast to int64.