System settings app crashes when doing the second checking for updates

[Evan Wang]

$ system-image-cli -i
current build number: 166
device name: turbo
channel: ubuntu-touch/rc-proposed/meizu-pd.en
last update: 2016-08-26 00:46:47
version version: 166
version ubuntu: 20160826
version device: 20160812-8b46c21
version custom: 20160805-985-8-9

Steps to reproduces:
1. Ubuntu One account signed in
2. Press option of 'Check for updates' from System Settings-->About-->Check for updates
3. Waiting for the updates checking is done, but do nothing then back to About page instead
4. Press 'Check for updates' again

Actual results:
System Settings crashed, quit directly.

[Bill Filler (bfiller)]

are there any crash files in /var/crash from system-settings, system-image-dbus or ubuntu-download-manager?

[Jonas G. Drange (jonas-drange)]

Got a trace here: http://pastebin.ubuntu.com/23113481/

[Bill Filler (bfiller)]

confirmed, can crash it everytime

[Jonas G. Drange (jonas-drange)]

One theory is that the plugin manager is not doing the right thing here, because if you, after step 3 exit the About panel, then enter it, then perform step 4—you get a warning from the plugin manager that “system-update” can't be found. The other theory is that the system-update plugin isn't cleaning up properly, which is unlikely because the bug cannot be triggered without going via the About panel.

Will confirm one or the other by changing the plugin instantiated by About with something closer to pure-qml, e.g. Hotspot—or create a brand new, empty one.

[Jonas G. Drange (jonas-drange)]

It crashes (albeit not as quickly) using the hotspot page, so this is
unrelated to System Update. It looks like a race in the plugin-manager.

[Launchpad Janitor (janitor)]

This bug was fixed in the package ubuntu-system-settings - 0.4+16.10.20160831.1-0ubuntu1

---------------
ubuntu-system-settings (0.4+16.10.20160831.1-0ubuntu1) yakkety; urgency=medium

  [ jonas-drange ]
  * fixes two crashes in About -> Check for update and Battery ->
    Brightness (LP: #1617217)

 -- Ken VanDine <email address hidden> Wed, 31 Aug 2016 15:19:48 +0000