Package must not call `LoadPackage`

[fingolfin]

This is not something a package should do:

InstallMethod(FerreroDesignCode,
"binary linear code constructed using a Ferrero design",
true, [IsList, IsInt], 0,
function( P,m)
 ...
    local C, f, H, K, M, D;
    LoadPackage("sonata");   # <- don't do this!!!!
    f := FpfAutomorphismGroupsCyclic( P, m );
    K := f[2];
    H := Group( f[1][1] );
    D := DesignFromFerreroPair( K, H, "*" );
    M := IncidenceMat( D );
    C := GeneratorMatCode(M*Z(2), GF(2));
    return C;
end);

I see two ways out: either declare sonata as a dependency of this package). Or move this function into a GAP "package extension", so that it becomes available as soon as sonata gets loaded.

In either case you'd remove the LoadPackage call.