Ubuntu 18.04: Trouble fixing bad install of Okular

[nought2]

Disregard statements about the Firefox Snap profile location. Now I don't see any in ~/.mozilla/firefox, except for the default Firefox. After installing a Firefox Snap, it clearly doesn't use the existing one as things need to be configured again.

It makes more sense for the profile to be kept within the same container as the FF Snap it belongs to.

More on parallel installs of the same snap application from two channels: This is a new possibility - learn about it here:
Snappy Lets You Install Multiple Versions of the Same Snap App
According to the article, simultaneous use of two versions is not recommended.

Thanks for this link. This is a useful feature, esp with FF where different profiles are often necessary for different roles. I hope the parallel-instances feature shifts from experimental to permanent.

Parallel-instances doesn't permit use of different iterations of the same Snap concurrently, that's OK. For FF Snap to have the potential to access different profiles by any other means is a close second.

For Firefox in MS Windows environments I have exclusively used the Portable Apps version for donkey's years. It's no-install, operates from a file, doesn't put its hooks into the system, can be removed cleanly & simply, which is similar to ambitions of AppImage, Flatpak, and Snap in Linux. I had multiple FF Port iterations each with a different profile. Years ago I learnt how to transfer profiles into FF Port copied from elsewhere. Still rely on this when I use Win10, can take FF profiles from Ubuntu with me.

I will have to play with Firefox Snap or Firefox ESR Snap sometime to see if I can locate where it stores the FF profile in Ubuntu. It would be useful to be able to save or substitute the profile of a FF Snap iteration.

Clues: Profile Manager - Create, remove, or switch Firefox profiles
Same methods would surely reveal path to FF Snap profile.

Thank you for the "snap install" and "snap switch" examples.

After switching FF channels does the refreshed FF use the same profile as the original did for that Snap iteration? Or does it begin again with a vanilla profile?

[Dennis N]

Profile for Snaps:
Firefox Snap profile location: ~/snap/firefox/common/.mozilla/firefox/

As I recall, after changing the tracking channel I did not need to re-do any settings, so same profile.

[nought2]

Just attempted to install Firefox Snap.

Installation process via terminal proceeded normally.

~$ snap install --channel=latest/stable firefox
firefox 79.0-1 from Mozilla✓ installed

But on attempting to launch FF Snap it crashes with this munged report:
20200804-FF-snap-crash-rpt-scnsht.png

I've come full circle in this thread. If I want to use Snap packages something will need to be repaired.

After imaging the system I'll remove all Snap components and installed Snaps, purge snapd, then reinstall snapd and see if I can get Snaps to install and work.

[Dennis N]

That's not a helpful error message. I've not had any error messages with installing or running snaps, so can't offer any useful help in that regard. Your idea may be the quickest route in the end.

[nought2]

My efforts were were unsuccessful.

Sequence of commands went like this:

~$ snap list  (to list installed snap packages)
~$ sudo snap remove <package> (all packages removed except "core 16-2.45.2", it cannot be removed)
~$ sudo snap purge snapd
~$ sudo apt autoremove
~$ rm -rf ~/snap  (remove /snap folder and its content from ~/home)

==> Restart system

~$ sudo apt install snapd
~$ sudo apt install gnome-software-plugin-snap  
~$ sudo apt update
~$ sudo apt upgrade

==> Restart system

At this point no Snaps were installed:

~$ snap list
No snaps are installed yet. Try "snap install hello-world"
~$ sudo snap install hello-world

After installing "hello-world" the "snap list" command output included only "core 16-2.45.2" and the test snap "hello-world".

I installed pdftk Snap. It's a simple command line tool. As far as I could tell it worked normally.

Then I installed Okular Snap and Firefox Snap. Each installation was concluded with a long pause while this notice displayed:
"Automatically connecting eligible plugins and slots of snap "package_name" "
Snap output claimed both installed successfully but neither would launch. Launch attempts produced the errors below:

~$ snap install okular
okular 20.04.0 from KDE✓ installed

~$ snap run okular
[error] cannot open locale definition file `en': No such file or directory
Qt: Session management error: None of the authentication protocols specified are supported
Icon theme "Adwaita" not found.
Fontconfig warning: FcPattern object width does not accept value [75 100)
Segmentation fault (core dumped)

~$ snap run firefox
Gtk-Message: 15:08:14.204: Failed to load module "canberra-gtk-module"
Gtk-Message: 15:08:14.205: Failed to load module "canberra-gtk-module"
Sandbox: /tmp/.X11-unix/X1 is inaccessible (No such file or directory); can't isolate network namespace in content processes
Gtk-Message: 15:08:14.969: Failed to load module "canberra-gtk-module"
Gtk-Message: 15:08:14.970: Failed to load module "canberra-gtk-module"
ExceptionHandler::GenerateDump cloned child 4327
ExceptionHandler::SendContinueSignalToChild sent continue signal to child
ExceptionHandler::WaitForContinueSignal waiting for continue signal...
Exiting due to channel error.

~$ Gtk-Message: 15:08:15.149: Failed to load module "canberra-gtk-module"
Gtk-Message: 15:08:15.150: Failed to load module "canberra-gtk-module"

Firefox launch attempt was accompanied by same munged crash report window posted yesterday.

Any clues on how to get Snap working properly?

Launch problems did not affect all installed Snaps. The GUI interfaces of p7zip-desktop and onlyoffice-desktopeditors lauched and functioned normally. No idea why they were spared from launch failure errors.

[Dennis N]

Here's my snap list from this computer (has Okular snap). Since yours 'sometimes works', compare your packages (other than applications) with mine. Install any you don't have one at a time and test again. This worked in another thread where one needed package was somehow not installed for that user.

dmn@Sydney-VM:~$ snap list
Name                             Version                     Rev   Tracking         Publisher   Notes
atari800-jz                      3.1.0-0                     1     latest/stable    jz          -
chromium                         84.0.4147.105               1244  latest/stable    canonical✓  -
core                             16-2.45.2                   9665  latest/stable    canonical✓  core
core18                           20200707                    1880  latest/stable    canonical✓  base
firefox                          79.0-1                      398   latest/stable    mozilla✓    -
gnome-3-26-1604                  3.26.0.20200529             100   latest/stable/…  canonical✓  -
gnome-3-28-1804                  3.28.0-17-gde3d74c.de3d74c  128   latest/stable    canonical✓  -
gnome-3-34-1804                  0+git.3009fc7               36    latest/stable    canonical✓  -
gnome-calculator                 3.36.0+git9.96b95fd2        748   latest/stable/…  canonical✓  -
gnome-characters                 v3.34.0+git8.a46106b        550   latest/stable/…  canonical✓  -
gnome-logs                       3.34.0                      100   latest/stable/…  canonical✓  -
gnome-system-monitor             3.36.0-12-g35f88a56d7       148   latest/stable    canonical✓  -
gtk-common-themes                0.1-36-gc75f853             1506  latest/stable    canonical✓  -
kde-frameworks-5-qt-5-14-core18  5.68.0                      4     latest/stable    kde✓        -
okular                           20.04.0                     98    latest/stable    kde✓        -
qogir-themes                     2020-02-26-25-g660f92c      2     latest/stable    gantonayde  -
quadrapassel                     3.36.02+git2.7edd2a1        283   latest/stable    canonical✓  -
snap-store                       3.31.1+git187.84b64e0b      415   latest/stable    canonical✓  -

Comments:
Okular probably wouldn't need any of the 'gnome' items, but Firefox might.
Also, 'gtk-common-themes' package should contain Adwaita theme that appears in one message.

One thing I haven't discovered about Snaps is how to determine if there are any unneeded resource packages here that could be removed. That's possible in Flatpak.

Added comment:
The Okular snap (rev 98) is ver. 1.10.0 with a date 23 Apr 2020 - somewhat older than the Flatpak.

[nought2]

This was the snap list output before I performed the process of commands to remove all Snaps and snapd:

~$ snap list
Name                             Version                     Rev   Tracking       Publisher    Notes
canonical-livepatch              9.5.5                       95    latest/stable  canonical✓   -
core                             16-2.45.2                   9665  latest/stable  canonical✓   core
core18                           20200707                    1880  latest/stable  canonical✓   base
firefox                          79.0-1                      398   latest/stable  mozilla✓     -
gnome-3-28-1804                  3.28.0-17-gde3d74c.de3d74c  128   latest/stable  canonical✓   -
gnome-3-34-1804                  0+git.3009fc7               36    latest/stable  canonical✓   -
gtk-common-themes                0.1-36-gc75f853             1506  latest/stable  canonical✓   -
gtk2-common-themes               0.1                         13    latest/stable  canonical✓   -
kde-frameworks-5-core18          5.61.0                      32    latest/stable  kde✓         -
kde-frameworks-5-qt-5-14-core18  5.68.0                      4     latest/stable  kde✓         -
onlyoffice-desktopeditors        5.5.1                       43    latest/stable  onlyoffice✓  -
p7zip-desktop                    16.02.2                     220   latest/stable  ernytech     -
pdftk                            2.02-4                      9     latest/stable  smoser       -

After removing all Snaps and snapd I thought it would be best to install Snaps again from scratch so they could establish necessary relationships or connections with other elements of the OS as part of the install process, and for additional components to be downloaded and installed together with Snap.

This was the output of snap list before additions were made tonight:

~$ snap list
Name                             Version          Rev   Tracking       Publisher   Notes
core                             16-2.45.2        9665  latest/stable  canonical✓  core
core18                           20200707         1880  latest/stable  canonical✓  base
firefox                          79.0-1           398   latest/stable  mozilla✓    -
gnome-3-34-1804                  0+git.3009fc7    36    latest/stable  canonical✓  -
gtk-common-themes                0.1-36-gc75f853  1506  latest/stable  canonical✓  -
hello-world                      6.4              29    latest/stable  canonical✓  -
kde-frameworks-5-qt-5-14-core18  5.68.0           4     latest/stable  kde✓        -
okular                           20.04.0          98    latest/stable  kde✓        -
pdftk                            2.02-4           9     latest/stable  smoser      -

gtk-common-themes is already installed but Okular Snap cannot find/use its Adwaita theme.

I installed additional Snap components.
Here is the current output of snap list after making additions:

~$ snap list
Name                             Version                     Rev   Tracking       Publisher   Notes
core                             16-2.45.2                   9665  latest/stable  canonical✓  core
core18                           20200707                    1880  latest/stable  canonical✓  base
firefox                          79.0-1                      398   latest/stable  mozilla✓    -
gnome-3-26-1604                  3.26.0.20200529             100   latest/stable  canonical✓  -
gnome-3-28-1804                  3.28.0-17-gde3d74c.de3d74c  128   latest/stable  canonical✓  -
gnome-3-34-1804                  0+git.3009fc7               36    latest/stable  canonical✓  -
gtk-common-themes                0.1-36-gc75f853             1506  latest/stable  canonical✓  -
gtk2-common-themes               0.1                         13    latest/stable  canonical✓  -
hello-world                      6.4                         29    latest/stable  canonical✓  -
kde-frameworks-5                 5.47.0                      27    latest/stable  kde✓        -
kde-frameworks-5-core18          5.61.0                      32    latest/stable  kde✓        -
kde-frameworks-5-qt-5-14-core18  5.68.0                      4     latest/stable  kde✓        -
okular                           20.04.0                     98    latest/stable  kde✓        -
pdftk                            2.02-4                      9     latest/stable  smoser      -
snap-store                       3.31.1+git187.84b64e0b      415   latest/stable  canonical✓  -

For thoroughness I removed and reinstalled Okular Snap. When I attempted to run it I got the same error message in terminal. I did not remove and reinstall Firefox Snap; trying to run it from terminal produced same error message as before too.

Response to additional comment
I'm not fussed about having Okular Snap. Okular Flatpak already works well. Here I'm using Okular Snap to demonstrate the problem I'm having with Snap on my system.

Trial of snap-store did not produce a happy result. Characters were blocked out as in FF crash report. See screenshot:
20200806-snap-store-scnsht.png
Launch output from terminal:

~$ snap run snap-store
14:25:45:0250 Gs  enabled plugins: odrs, rewrite-resource, snap, icons, key-colors, key-colors-metadata
14:25:45:0250 Gs  disabled plugins: appstream, desktop-categories, desktop-menu-path, dpkg, dummy, epiphany, fedora-pkgdb-collections, generic-updates, hardcoded-blacklist, hardcoded-featured, hardcoded-popular, modalias, os-release, provenance, provenance-license, repos, shell-extensions
14:25:51:0347 Gs  failed to create an app for */*/*/*/system/*
14:25:51:0348 Gs  updates-shell: failed to get updates: no plugin could handle get-updates
14:25:51:0348 Gs  failed to create an app for */*/*/*/system/*
14:25:51:0348 Gs  failed to get system app
14:25:51:0348 Gs  Only 0 apps for recent list, hiding
14:25:52:0750 Gs  hiding category graphics featured applications: found only 0 to show, need at least 9
14:25:52:0758 Gs  hiding category audio-video featured applications: found only 0 to show, need at least 9
14:25:53:0375 GLib g_variant_new_variant: assertion 'value != NULL' failed
14:25:53:0375 GLib g_variant_new_variant: assertion 'value != NULL' failed
14:25:53:0376 Gs  not GsPlugin error g-io-error-quark:35: Invalid string value converting to GVariant
14:25:53:0376 Gs  not handling error failed for action refine: Invalid string value converting to GVariant
14:25:53:0890 GsPluginSnap Failed to load snap icon: local snap has no icon
14:25:54:0928 GsPluginSnap Failed to load snap icon: local snap has no icon
14:25:55:0439 GsPluginSnap Failed to load snap icon: local snap has no icon

[Dennis N]

Firefox: Exiting due to channel error:
Bug - https://bugzilla.mozilla.org/show_bug.cgi?id=1538435
Some reports here are for Firefox snap version.

Okular: Segmentation fault.
It crashed for some reason. We're clueless.

When starting from terminal, various messages (some labeled as errors) are not uncommon. If I run Firefox snap from terminal:

dmn@Sydney-VM:~$ snap run firefox
Gtk-Message: 08:38:15.286: Failed to load module "canberra-gtk-module"
Gtk-Message: 08:38:15.317: Failed to load module "canberra-gtk-module"
Sandbox: /tmp/.X11-unix/X0 is inaccessible (No such file or directory); can't isolate network namespace in content processes
Gtk-Message: 08:38:32.961: Failed to load module "canberra-gtk-module"
Gtk-Message: 08:38:32.962: Failed to load module "canberra-gtk-module"
Gtk-Message: 08:38:33.806: Failed to load module "canberra-gtk-module"
Gtk-Message: 08:38:33.808: Failed to load module "canberra-gtk-module"
Gtk-Message: 08:38:34.056: Failed to load module "canberra-gtk-module"
Gtk-Message: 08:38:34.057: Failed to load module "canberra-gtk-module"
extension-storage: migration complete
Gtk-Message: 08:38:36.033: Failed to load module "canberra-gtk-module"
Gtk-Message: 08:38:36.034: Failed to load module "canberra-gtk-module"
Gtk-Message: 08:38:36.505: Failed to load module "canberra-gtk-module"
Gtk-Message: 08:38:36.510: Failed to load module "canberra-gtk-module"

After this Firefox is running normally.

Okular throws lots of messages too. I get 123 lines of FontConfig errors and warnings. Plus this Qt error that you have as well:

Qt: Session management error: None of the authentication protocols specified are supported

but this Okular snap still works normally.

System details:

dmn@Sydney-VM:~$ snap --version
snap    2.45.2
snapd   2.45.2
series  16
ubuntu  19.10
kernel  5.3.0-64-generic

I had to use 19.10 (it's a virtual machine) only because that's were I installed the Okular snap to test it.

[nought2]

Firefox: Exiting due to channel error:
Bug - https://bugzilla.mozilla.org/show_bug.cgi?id=1538435
Some reports here are for Firefox snap version.

Majority of bug reports there are for development versions of FF. Strife with them is expected.

The Snap problems on my system are probably of a different nature and are likely to stem from the usage history of Snap.

Exploring the problem in this thread has refreshed my memory of what I did to cause the malaise. At the time I first installed Snap packages I had no idea what they were and what their installation process entailed. Specifically, I didn't realise the size of the download required for self-contained Snap packages and how long it would take to pull them down from the cloud.

Early on I had installed a few Snaps successfully via the Ubuntu Software GUI. Some time later when installing Okular Snap nothing seemed to happen. In the background the package was downloading, but I didn't realise that, there was no indication in the GUI it was taking place. Impatient to see a result of my action I hit the install button numerous times.

While at that time Okular Snap was installed it would not run. Okular installed via apt ran OK but was not latest version. Yada. We've already covered this ground.

Occasionally when navigating around Ubuntu 18.04's GUI I would see evidence of the multiple Snap install attempts. IIRC, when selecting the default PDF viewer from a list there was ~10 appearances of Okular on top of each other. The number of appearances likely corresponded to the number of install requests/attempts I had made.

Snap packages installed prior to Okular Snap worked normally. When such apps were searched in the Ubuntu Software GUI their standard icon would appear.

Today I reinstalled p7zip-desktop. It's a pretty lightweight app, only a GUI for a file compression utility. The installed package launches and appears to work. But its proper icon is missing from Ubuntu Software, instead the generic mauve diamond with gear motifs appears. Another manifestation of the perturbation of Snap on this system.

To remedy the problem, if it is possible, needs more than removing, purging, reinstalling various elements of Snap.

System info:

~$ snap --version
snap    2.45.2
snapd   2.45.2
series  16
ubuntu  18.04
kernel  4.15.0-112-generic

[Dennis N]

Your experience with the initial install of snap reminds me of mine. Using (Gnome) Software, there was no feedback as to progress. Fortunately, I let it be for awhile instead of aborting. Now, I would rather install from the terminal, since it does show what is happening.

You can supply the icon for a snap. The atari800-jz snap didn't provide an icon. I copied the snap's .desktop file to ~/.local/share/applications and included an Icon= line. That worked. This also gives us a way to change the displayed name.