Cannot build GauXC offline

[awvwgk]

When building GauXC with all dependencies preinstalled (ExchCXX, IntegratorXX, HDF5, BLAS, catch2, etc.) the linalg-modules will always be fetched as part of the build, which will fail if the build machine can't access GitHub.

Thanks to Franz @franzpoeschel for raising this issue.

[wavefunction91]

Hey @awvwgk, bundling as a tarball solves the release problem, but it does not solve the "build from main problem", which is arguably the more important one. Can you provide a concrete situation in which you're running into this problem? Presumably you had to have internet access at some point to get the source?

[franzpoeschel]

Multiple situations:
Currently, I think that this problem affects only the linalg-modules (when I first tried building GauXC, there was a handful of dependencies that were online-only).

Generally, online builds break all setups that require user control over downloads. This includes deterministic build systems (e.g. CP2K has a Nix distribution), or build scripts on systems that have restricted Internet access on compute nodes.

For development purposes, allowing user-supplied versions significantly simplifies development inside of complex software dependencies (e.g. tracking bugs that occur in a dependency).

More generally, this is not only about online/offline, but about control over dependencies. You might want to set specific configure option for a dependency, the dependency might already be in the system, a package manager might prefer to have separate packages for dependencies, you might want to control where to install a dependency, …

It is nice to have automatic downloads for those users who don't care about such things, but there is no way to do that without taking away control from the user.