Platform connection not working

[fcole90]

I tried running a snapped gnome app, but it required to be connected, but still it didn't work.

Following, what happened in detail:

-----------------------------------------------------------------------
$ snap run evince
You need to connect this snap to the gnome platform snap.

You can do this with those commands:
$ snap install gnome-3-26-1604
$ snap connect evince:gnome-3-26-1604 gnome-3-26-1604

(the '3-26-1604' number defines the platform version and might change)
$ snap install gnome-3-26-1604
snap "gnome-3-26-1604" is already installed, see 'snap help refresh'
$ snap connect evince:gnome-3-26-1604 gnome-3-26-1604
$ snap install gnome-3-26-1604
snap "gnome-3-26-1604" is already installed, see 'snap help refresh'
$ snap run evince
You need to connect this snap to the gnome platform snap.

You can do this with those commands:
snap install gnome-3-26-1604
snap connect evince:gnome-3-26-1604 gnome-3-26-1604

(the '3-26-1604' number defines the platform version and might change)
----------------------------------------------------------------------

As you can see either the message is wrong or the platform was not connected.

This all happened after I removed and then reinstalled the gnome-platform snap. After reinstalling it, it displayed that it connected to all the apps which depended on it.

Workaround: removed and reinstalled evince snap, now it works.

Additional comment 1: I had removed the gnome platform as it was 3.26 but gnome apps are 3.28, so I assumed it was an old version. It turned out gnome-3-26-1604 likely contains code for gnome 3.28 apps, which is quite counterintuitive.

Additional comment 2: I discovered that when I tried to open PDF documents nothing was happening, so I remembered evince was a snap app. I think some gui message to inform the user of such errors is needed.

ProblemType: Bug
DistroRelease: Ubuntu 18.04
Package: snapd 2.34.2+18.04
ProcVersionSignature: Ubuntu 4.15.0-33.36-generic 4.15.18
Uname: Linux 4.15.0-33-generic x86_64
ApportVersion: 2.20.9-0ubuntu7.2
Architecture: amd64
CurrentDesktop: communitheme:ubuntu:GNOME
Date: Fri Aug 31 17:02:41 2018
InstallationDate: Installed on 2017-08-21 (374 days ago)
InstallationMedia: Ubuntu 17.10 "Artful Aardvark" - Alpha amd64 (20170820)
SourcePackage: snapd
UpgradeStatus: No upgrade log present (probably fresh install)