On Mon, Jan 18, 2021 at 09:57:32AM +0100, Wiktor Żelazny wrote: > $ guix time-machine --commit=d81fb2ae9443994ae5dd1cb5837276fad63f842c --channels=channel-specs.scm -- \ > build --with-source=r-foreign=foreign_0.8-75.tar.gz r-foreign > /gnu/store/jvh9zyym3xmzy94g37gx5klg8rx72vfj-r-foreign-75 A step forward: $ guix time-machine --commit=d81fb2ae9443994ae5dd1cb5837276fad63f842c --channels=channel-specs.scm -- \ build --with-source=r-foreign@0.8-75=foreign_0.8-75.tar.gz r-foreign@0.8-75 results in a path with the correct version. However, subsequent `guix time-machine -- environment` ignores is, downloads the source from CRAN, and complaints about the hash. WŻ