Updating Guix requires full rebuild?

[Jookia]

Hey there,

I've been compiling and installing Guix without any substitutes, however I've
hit a problem. I've managed to compile Guix, then compile Guix using Guix. But
when I try to do anything using the Guix managed by Guix, it wants to rebuild
everything on my system. I've uploaded some raw data,[1] comparing the outputs
of the old and new Guix binaries and accompanying binaries as well as with and
without the --bootstrap flag. The package being inspected is 'tar'.

It would seem like this is a major problem considering both Guix packages are
identical aside from the host code having the Guix package derivation updated
to use the same Git version as the host version of Guix. The tar packages aren't
modified in any way and neither is any thing I would expect to be used to build
a derivation, such as a builder script.

Cheers,
Jookia.

[1]: uhoh.tar.bz2: https://infotomb.com/2dp3c