Simon Tournier writes: > Hi Chris, > > On Fri, 17 Nov 2023 at 21:39, Christopher Baines wrote: > >> The bordeaux build farm depends on computing the derivations on one >> machine, then potentially building them on a different machine. >> >> Some of the build machines don't have a new enough guix-daemon that >> understands builtin:git-download, so derivations that use this are >> sometimes failing (e.g. [1]) > > Do you mean that the drv file is generated using a new daemon then this > drv file is “offloaded” to another machine using an older daemon and > thus fails to build it? Roughly, yep. >> One potential approach to address this is somehow have the data service >> indicate that it wants compatible derivations when computing them, >> rather than to have guix do feature detection against the guix-daemon >> that is being used at the point the derivations are being computed. > > Other solutions are: downgrade the daemon of one of the machine or > update the daemon of other machines, no? > > Why would the latter not be possible? It's possible, just difficult. Because with the current guix-daemon, the build coordinator can only build things that can be GC'd, some machines deliberately run older daemons to allow building newer things without hitting this issue.