This is a Python wrapper (using CFFI) around Linux's renameat2 system call. With renameat2, you can atomically swap two files, choose if existing files are replaced, and create "whiteout" files for overlay filesystems.
This package requires Python 3.6. I tried building it for Python 3.5 and got some syntax errors with the type declarations. I don't care about Python 3.5 personally so I didn't bother fixing it. If you care about Python 3.5 and want to write a patch to make it work there too, I would consider merging it.
This package requires Linux, because renameat2 is a Linux-specific system call. Your kernel must be version 3.15.0 or newer to use renameat2; it does not exist in older kernels. Importing this module will raise a RuntimeError if you are not running on Linux or if your kernel is older than 3.15.0.
This package does not have any libc requirements; glibc includes a wrapper for renameat2 in version 2.28 and newer, but this is significantly newer than the glibc in any of the manylinux containers. In order to avoid inflicting any libc requirements on the user, this package brings its own wrapper function that makes the system call directly.
Stableish? It's just a single system call and I can't imagine doing too much more with the interface. I did use this project to brush about 11 years of dust off of my Python packaging techniques, though, so let me know if you see anything amiss. Pull requests are welcome.
This package is provided under the MIT License.