Behaviour inconsistency between apt and aptitude (on nvidia-related packages)

[Sven Joachim]

On 2018-09-26 10:38 -0400, Boyuan Yang wrote:

> I just encountered some weird problem around installing bumblebee-nvidia using 
> apt and aptitude on Debian Unstable. Here's what I did:
>
> $ sudo apt purge '*nvidia*'
> $ sudo apt autoremove --purge
> $ sudo apt update
> $ dpkg --print-architecture
> amd64
> $ dpkg --print-foreign-architectures
> i386
>
> For apt:
>
> $ sudo apt install bumblebee-nvidia primus- nvidia-driver-
> Reading package lists... Done
> Building dependency tree       
> Reading state information... Done
> Package 'primus' is not installed, so not removed
> Package 'nvidia-driver' is not installed, so not removed
> The following additional packages will be installed:
>   bbswitch-dkms bumblebee dkms glx-alternative-mesa glx-alternative-nvidia 
> glx-diversions libegl1-nvidia-legacy-340xx libgl1-nvidia-legacy-340xx-glx
>   libnvidia-legacy-340xx-eglcore libnvidia-legacy-340xx-glcore libnvidia-
> legacy-340xx-ml1 linux-headers-amd64 nvidia-installer-cleanup nvidia-kernel-
> common:i386
>   nvidia-legacy-340xx-alternative nvidia-legacy-340xx-driver nvidia-
> legacy-340xx-driver-bin nvidia-legacy-340xx-driver-libs nvidia-legacy-340xx-
> kernel-dkms
>   nvidia-legacy-340xx-kernel-support:i386 nvidia-legacy-340xx-vdpau-driver 
> nvidia-modprobe:i386 nvidia-support update-glx xserver-xorg-video-nvidia-
> legacy-340xx
> Suggested packages:
>   python3-apport menu nvidia-driver
> Recommended packages:
>   virtualgl | primus nvidia-settings-legacy-340xx nvidia-persistenced nvidia-
> legacy-340xx-driver-libs-i386 libgles1-nvidia-legacy-340xx libgles2-nvidia-
> legacy-340xx
>   libnvidia-legacy-340xx-cfg1
> The following NEW packages will be installed:
>   bbswitch-dkms bumblebee bumblebee-nvidia dkms glx-alternative-mesa glx-
> alternative-nvidia glx-diversions libegl1-nvidia-legacy-340xx libgl1-nvidia-
> legacy-340xx-glx
>   libnvidia-legacy-340xx-eglcore libnvidia-legacy-340xx-glcore libnvidia-
> legacy-340xx-ml1 linux-headers-amd64 nvidia-installer-cleanup nvidia-kernel-
> common:i386
>   nvidia-legacy-340xx-alternative nvidia-legacy-340xx-driver nvidia-
> legacy-340xx-driver-bin nvidia-legacy-340xx-driver-libs nvidia-legacy-340xx-
> kernel-dkms
>   nvidia-legacy-340xx-kernel-support:i386 nvidia-legacy-340xx-vdpau-driver 
> nvidia-modprobe:i386 nvidia-support update-glx xserver-xorg-video-nvidia-
> legacy-340xx
> 0 upgraded, 26 newly installed, 0 to remove and 0 not upgraded.
> Need to get 23.7 MB of archives.
> After this operation, 137 MB of additional disk space will be used.
> Do you want to continue? [Y/n]
>
> And for aptitude:
>
> $ sudo aptitude install bumblebee-nvidia primus- nvidia-driver-
> Package primus is not installed, so it will not be removed
> Package nvidia-driver is not installed, so it will not be removed
> Package primus is not installed, so it will not be removed
> Package nvidia-driver is not installed, so it will not be removed
> The following NEW packages will be installed:
>   bbswitch-dkms{a} bumblebee{a} bumblebee-nvidia dkms{a} glx-alternative-
> mesa{a} glx-alternative-nvidia{a} glx-diversions{a} libegl-mesa0:i386{a} 
> libegl-nvidia0{a} 
>   libegl-nvidia0:i386{a} libegl1:i386{a} libgbm1:i386{a} libgl1-nvidia-glvnd-
> glx{a} libgl1-nvidia-glvnd-glx:i386{a} libgles-nvidia2:i386{a} 
> libgles2:i386{a} 
>   libglx-nvidia0{a} libglx-nvidia0:i386{a} libnvidia-cfg1:i386{a} libnvidia-
> egl-wayland1{a} libnvidia-egl-wayland1:i386{a} libnvidia-eglcore{a} 
>   libnvidia-eglcore:i386{a} libnvidia-glcore{a} libnvidia-glcore:i386{a} 
> libnvidia-ml1{a} libopengl0:i386{a} libvulkan1:i386{a} libwayland-
> client0:i386{a} 
>   libwayland-server0:i386{a} libxnvctrl0{a} linux-headers-amd64{a} nvidia-
> alternative{a} nvidia-driver-libs:i386{a} nvidia-driver-libs-i386:i386{a} 
>   nvidia-egl-common{a} nvidia-egl-icd:i386{a} nvidia-egl-wayland-common{a} 
> nvidia-egl-wayland-icd:i386{a} nvidia-installer-cleanup{a} nvidia-kernel-
> common{a} 
>   nvidia-kernel-dkms{a} nvidia-kernel-support{a} nvidia-legacy-check{a} 
> nvidia-modprobe{a} nvidia-settings{a} nvidia-support{a} nvidia-vdpau-driver{a} 
>   nvidia-vulkan-common{a} nvidia-vulkan-icd{a} nvidia-vulkan-icd:i386{a} 
> update-glx{a} xserver-xorg-video-nvidia{a} 
> The following packages are RECOMMENDED but will NOT be installed:
>   libcuda1 nvidia-driver primus 
> 0 packages upgraded, 53 newly installed, 0 to remove and 0 not upgraded.
> Need to get 49.1 MB of archives. After unpacking 201 MB will be used.
> Do you want to continue? [Y/n/?]
>
> As you can see, the behaviour of apt is expected (choosing an dependency from 
> alternative list when a dependency "nvidia-driver" is not to be installed) but 
> aptitude is giving a weird answer: it just ignored the hard dependnecy that 
> "bumblebee-nvidia depends on nvidia-driver | ... " but downgraded this 
> dependency to "RECOMMENDED but will NOT be installed". That is really strange 
> since aptitude seems to have ignored a hard dependency.

It didn't, it just chose to install nvidia-kernel-dkms rather than
nvidia-legacy-340xx-driver.  The installation of various 386 packages is
certainly odd and probably not what you want, but I am pretty sure that
aptitude's solution is valid, if suboptimal.

The xserver-xorg-video-nvidia package recommends nvidia-driver, so the
"RECOMMENDED but will NOT be installed" statement is also explained.

Cheers,
       Sven