libbamf: BamfView child cache not reloading

[Cs-gon]

When applications close and re-open their window and BamfView changed its path, the child cache of BamfView does not reload its children and continues to work with the old cache, which does not contain any children. The application icon in Unity then does not do anything (cannot raise the application window, activate a minimized window or Alt-Tab to the window).

This problem shows up for us mainly when using the Citrix Receiver, but other applications can trigger this too.

This problem exists in Trusty and Yaketty (maybe older versions too, I haven't checked those), and the attached patch fixes the problem (fixes the handling of the reload_children boolean).

I think the following bug report might be the same problem:

https://bugs.launchpad.net/ubuntu/+source/bamf/+bug/1326903

[Cs-gon (cs-gon)]

Did anyone look into this? If not, could you please take a look?

The attached patch provides an obvious and simple (one line) fix, and it would be great to see this fixed in bamf, to prevent "losing" application windows, because the corresponding Unity icon does not do anything and the windows also don't show up in the task switcher.

These basic window handling bugs can really be a pain, and it took me quite some time to find the root cause, so I would really appreciate it getting integrated into the upstream bamf code.

And it seems all versions from trusty up to yakkety are affected.

Thanks!

[Ubuntu Foundations Team Bug Bot (crichton)]

The attachment "fix_bamf_view_child_caching.patch" seems to be a patch. If it isn't, please remove the "patch" flag from the attachment, remove the "patch" tag, and if you are a member of the ~ubuntu-reviewers, unsubscribe the team.

[This is an automated message performed by a Launchpad user owned by ~brian-murray, for any issues please contact him.]

[Cs-gon (cs-gon)]

Hello? Anyone? How can I get you to integrate this obvious and simple fix for a pretty annoying bug? It's nearly 4 months since I opened this bug report.

This should most probably fix https://bugs.launchpad.net/ubuntu/+source/bamf/+bug/1326903 , which is classed as a high importance bug, and still exists in Yakkety (but more importantly for us in Trusty and Xenial, because we use the LTS releases).

And this fixes a usability problem in Unity. From the bug description: "... The application icon in Unity then does not do anything (cannot raise the application window, activate a minimized window or Alt-Tab to the window)."

[Khurshid Alam (khurshid-alam)]

Is this still a problem with 18.04?

[Khurshid Alam (khurshid-alam)]

@Cs-gon (cs-gon)

If you are getting this messages please reply.

[Cs-gon (cs-gon)]

@khurshid-alam

Sorry for responding so late.

As far as I can see, the patch wasn't applied to the bionic tree of bamf, so I think this should still be a problem in 18.04, but I haven't tested this.

I have only experience with Unity and bamf in 16.04 and it seems that there were some Unity changes which mask the problem, or at least make it harder to reproduce. But that doesn't change, that I think that the cache reloading logic is wrong, and that it can lead to problems as described in my initial bug report.

[Khurshid Alam (khurshid-alam)]

In Ubuntu > 17.04, syslog spams like this:

hudservice: "No such interface “com.canonical.dbusmenu” on object at path /org/ayatana/bamf/window/67108888"

obviously /org/ayatana/bamf/window/67108888 doesn't exists among active applications. So no only cache reloading but application matcher is also doing something wrong. I want to combine two bugs into one and proposes a fix for both bamf and hud/unity.