torchvision[cuda10] installs default pytorch build, instead of cuda10 build

torchvision and pytorch are required to be built in similar environment.
Currently, when calling pip-install on cuda10 build of torchvision, (if torch is not already installed) it implicitly installs the default Pytorch build, which - as of today - is built against cuda9, resulting in raising an error during run-time.

e.g.
pip install torchvision[cuda10_package] torch[cuda10_package] - will work
but:
pip install torchvision[cuda10_package]; pip install torch[cuda10_package]
or similarily, pip install torch[cuda10_package] torchvision; pip install --force torchvision[cuda10_package]
will not. (order matters)

Can the requirements of each build be specified in such a way that pip will automatically look for the matching build of pytorch?
Alternatively, is it possible for pip to independently decide the correct build based on environment variables?

The issue names no repository files or tests. First reproduce the listed pip install orders with the CUDA10 package variants and inspect how their dependency metadata is resolved; done means both installation orders select matching PyTorch and torchvision builds without requiring a preinstalled torch package.