Simon,

zimoun 写道：
> I am often annoyed because when I run "guix upgrade", Guix
> downloads again the heavy texlive-20190410-texmf.tar.xz if I 
> have
> forgotten to protect it from "guix gc" using the trick, e.g.,
>
>   https://lists.gnu.org/archive/html/help-guix/2020-02/msg00110.html
>
> What could be a more general solution independent of the trick?

You might be happy with ‘--gc-keep-outputs’.

From (guix)Invoking guix-daemon:

‘--gc-keep-outputs[=yes|no]’
     Tell whether the garbage collector (GC) must keep outputs of 
     live
     derivations.

     When set to ‘yes’, the GC will keep the outputs of any live
     derivation available in the store—the ‘.drv’ files.  The 
     default is
     ‘no’, meaning that derivation outputs are kept only if they 
     are
     reachable from a GC root.  *Note Invoking guix gc::, for more 
     on GC
     roots.

‘--gc-keep-derivations[=yes|no]’
     Tell whether the garbage collector (GC) must keep derivations
     corresponding to live outputs.

     When set to ‘yes’, as is the case by default, the GC keeps
     derivations—i.e., ‘.drv’ files—as long as at least one of 
     their
     outputs is live.  This allows users to keep track of the 
     origins of
     items in their store.  Setting it to ‘no’ saves a bit of disk
     space.

     In this way, setting ‘--gc-keep-derivations’ to ‘yes’ causes
     liveness to flow from outputs to derivations, and setting
     ‘--gc-keep-outputs’ to ‘yes’ causes liveness to flow from
   ▶ derivations to outputs.  When both are set to ‘yes’, the 
   effect is
   ▶ to keep all the build prerequisites (the sources, compiler,
   ▶ libraries, and other build-time tools) of live objects in the
     store, regardless of whether these prerequisites are 
     reachable from
     a GC root.  This is convenient for developers since it saves
     rebuilds or downloads.

Kind regards,

T G-R