How to make locations available to a snap when --classic gets ignored?

Question

I would like to make use of VLC on Ubuntu. The developers of VLC claim they won't support the Debian packages anymore and Snap packages are the way to go. Quote (as of 2020-04-12):

Nota Bene

VLC for Ubuntu and many other Linux distributions is packaged using snapcraft. This allows us to distribute latest and greatest VLC versions directly to end users, with security and critical bug fixes, full codec and optical media support.

If you wish to install the traditional deb package, it is available as usual via APT, with all security and critical bug fixes. However, there will be no major VLC version updates until the next Ubuntu release.

I have been using VLC on Ubuntu 18.04 for some time now (and 20.04 beta recently), but I always run into the following issue:

The remedy I found by reading the documentation seemed to be to install the vlc Snap package in "classic" mode. It appears that this is meant to disable certain security measures and basically let the snap access everyting.

sudo snap install --classic vlc

Alas, when I try installing VLC this way I get:

$ sudo snap install --classic vlc
Warning: flag --classic ignored for strictly confined snap vlc

vlc 3.0.8 from VideoLAN✓ installed

... and indeed nothing changes because it appears the --classic flag is being ignored.

Strangely enough some locations are available. For example everything auto-mounted into /media/$(whoami) when I attach a USB disk or so, it's available to VLC.

Question: So how can I use the snap package in combination with the ability to access any file system location (at least read only) which I am able to access with my normal unprivileged user account?

---

Additional information:

$ sudo snap connections |grep vlc:
desktop                   vlc:desktop                                :desktop                         -
desktop-legacy            vlc:desktop-legacy                         :desktop-legacy                  -
home                      vlc:home                                   :home                            -
network                   vlc:network                                :network                         -
network-bind              vlc:network-bind                           :network-bind                    -
opengl                    vlc:opengl                                 :opengl                          -
optical-drive             vlc:optical-drive                          :optical-drive                   -
pulseaudio                vlc:pulseaudio                             :pulseaudio                      -
removable-media           vlc:removable-media                        :removable-media                 -
screen-inhibit-control    vlc:screen-inhibit-control                 :screen-inhibit-control          -
unity7                    vlc:unity7                                 :unity7                          -
x11                       vlc:x11                                    :x11                             -
$ mount|grep /data
/dev/nvme1n1p4 on /data type btrfs (rw,relatime,ssd,space_cache,subvolid=5,subvol=/)

Answer 1

A possible solution (and right now it seems the only one, according to this bug) is to mount /dev/nvme1n1p4 in a subfolder of /home/youruser or subfolder of /media.

The bug has detailed information about the reasons that, right now, make it impossible for a VLC snap to access arbitrary folders (even if you want to grant that access).

The folders /home and /media are hardcoded in the code via plugins, that list all the resources a snap will have access to once built by snapcraft. That's why mounting under those folders will work.