On Tuesday, 2 April 2024 07:03:42 BST J. Roeleveld wrote:
> On Monday, 1 April 2024 23:46:49 CEST John Covici wrote:
> > Hi.  Well, I followed the steps in the news item,  to move
> > todefault/linux/amd64/23.0/desktop/gnome/systemd
> > 
> > and it all worked till it wants me to emerge  the whole world file.
> > Here is what I get:
> > 
> > emerge --ask --emptytree @world
> > 
> > These are the packages that would be merged, in order:
> > 
> > Calculating dependencies  .... done!
> > Dependency resolution took 4.58 s (backtrack: 0/200).
> > 
> > 
> > !!! Problems have been detected with your world file
> > !!! Please run emaint --check world
> > 
> > 
> > !!! Ebuilds for the following packages are either all
> > !!! masked or don't exist:
> > www-apps/nextcloud:26.0.10
> > 
> > emerge: there are no ebuilds to satisfy
> > "sys-kernel/gentoo-sources:6.1.69".
> > (dependency required by "@kernels" [set])
> > (dependency required by "@selected" [set])
> > (dependency required by "@world" [argument])
> > 
> > I don't want to unmerge that kernel -- its my backup kernel, so I
> > definitely want to keep it.  I am using the nextcloud they are
> > complaining about , I will upgrade it soon, but I want to keep it for
> > now.
> 
> Do you actually need to keep the kernel-sources?
> Once the kernel is compiled and you moved the image to /boot/..., you don't
> need to keep the sources.
> 
> I also keep an older kernel just in case, but I don't tend to actually keep
> the sources around once I have confirmed the new kernel will boot.
> 
> --
> Joost

When gentoo-sources are tree-cleaned, it is typically because they have been 
superseded by later kernel patches to improve security and resolve bugs.  
Therefore it is usually a 'good idea' to emerge a later kernel when this 
happens, even if we're talking about a backup kernel.

Last week I came upon a similar problem on an old system I was trying to 
migrate to profile 23.0, only this happened not with my backup but with the 
running kernel.  This PC had not been updated for 5-6 months.  It's resource 
constrained and I didn't want to spend many days updating most of its 
deprecated packages, only to have to re-emerge them as part of the profile 
migration.  I can't recall if it was the same kernel as John's.  During the 
migration I came across some package (llvm?) which required a more up to date 
kernel to be able to emerge.  This forced me to upgrade the kernel first, 
before I could continue with the migration.  I'm mentioning this since the 
utility of a backup kernel would be limited when you can't use it to run your 
software.