Demi Marie Obenour <demiobenour@gmail.com> writes:

> On 7/16/25 17:16, Demi Marie Obenour wrote:
>> I'm working on it, but I ran into a problem: I can't install vim in the guest!
>> Adding it to the list of packages doesn't work; I still don't have a Vim binary
>> in the guest.  Without that, I have to rebuild the VM every time I want to make
>> a change, which makes it very hard to iterate while I figure out how to make
>> PipeWire talk to an emulated virtio-sound device QEMU provides.
>
> Deleting the build directory causes the image to be rebuilt.

I've pushed a change that causes a rebuild if the list of packages has
changed.  You'll still need to exit and re-enter the Nix shell (or use
something like direnv that automatically refreshes that for you), but
there's no longer a need to delete the build directory after that.  We
could also implement rebuilds when other environment variables from Nix
change.

(The reason I think this change makes sense, but not your Makefile
dependency patch, is that this only needs a dependency to be added to
specific targets that use that value, and because it's solving an
integration problem between Nix and Make, rather than trying to change
normal Make functionality.)