Hi Aaron,

The key trick was to make iotbx only depend on dxtbx if dxtbx is explicitly configured.  I used a keyword in libtbx_configure added by Luc a bit ago: optional_modules_only_if_explicit_request.  I committed that change just now.

That is exactly the use case I envisioned. What I planned to use it for never made it to the official repo but it’s always nice to see it being useful to somebody else!

Outstanding questions:

1. Is there interest in making this a builder? It would be straightforward to add a builder named cctbx_minimal which would just do the above steps

I would like to have that. For reasons different from yours, I guess. But still, first, this would make our life easier at Bruker. Then there is also the teaching facet of the cctbx: I am regularly involved in the computing schools organised by the IUCr and the ECM where I give tutorials on the cctbx, and having a forced dependency on dxtbx with the added chore of an implicit dependency on HDF5 is annoying.

Best wishes,

Luc