So Pants can infer the dependency on a PEX file for building a Docker image by reading the COPY command in a Dockerfile. It can then trigger PEX build rather than rely on pre-building. But can it also infer any requirements for cross-building and thus cross-build that same PEX for the platform of the Docker image?

Thanks for the reply but my docker image is not using python, so I didn’t understand really the PEX stuff

It does not do anything regarding platforms/cross building. It merely builds the target so it must have the proper field values setup to work for you target image environment.