Update for gnome shell 42

[lumbric]

This is a quick draft to make things compatible with gnome shell 42.9.

Note that this is my first time touching gnome extensions and I have very limited know how - please use this PR with caution.

I simply debugged the thing until it was working with my version of GNOME Shell. No idea which versions are actually compatible. But you can easily modify the metadata.json and add other GNOME Shell versions and test it there.

$ gnome-shell --version
GNOME Shell 42.9

What I had to do to get it working again:

• use the GObject.registerClass() function and use ES 6 class instead of an object for the indicator. I'm not entirely sure why this is necessary, I basically guessed it from the error message and a comparison to a working extension which I created from a template using the gnome-extensions-tool by running gnome-extensions create --interactive and choosing "indicator" as template. There are also some hints regarding migrating shell classes here.
• I had to declare all variables. No idea why. I just put a let wherever necessary.
• I had to adapt the prefs.xml: I simply followed the error messages and got some inspiration by running gtk4-builder-tool simplify --3to4 prefs.xml - but the automatically converted xml did not show any dialog - just the empty window. Basically margin and GtkVBox has been removed as far as I understand.

Thanks to @petres for the help! 💜

This may fix #7.

[lumbric]

Others might find this PR when porting a GNOME Shell extension and googling for the error messages, so let's put the error messages here and some quick hints what helped me getting this extension running again:

(See commits for this PR for details.)

Error 1

Object 0xb70d1a269e8 is not a subclass of GObject_Object, it's a Object

Resolution: convert to ES6 classes and use `GObject.registerClass()?

Error 2

assignment to undeclared variable SOME_VARIABLE_NAME

Resolution: use letto declare all variables.

Error 3

Gtk.BuilderError: /home/my_user./local/share/gnome-shell/extensions/[email protected]/prefs.xml:38:29 Invalid property: GtkGrid.margin

Resolution: simply remove this property from the xml. Seems to look good enough.

Error 4

Gtk.BuilderError: /home/peter/.local/share/gnome-shell/extensions/[email protected]/prefs.xml:44:1 Invalid object type 'GtkVBox'

Resolution: Change GtkVBox to GtkBox in the prefs.xml. Then child objects are not aligned vertically, so you probably want to add <property name="orientation">vertical</property> (this is what the gtk4-builder-tool suggested and it seems to work fine).

Error 5

TypeError: box.show_all is not a function

Resolution: Simply remove the line box.show_all();, returning the object seems to be fine. I've been inspired by phocean/TopIcons-plus#156 and UshakovVasilii/gnome-shell-extension-freon#195.

[tassos]

thanks for the effort @lumbric! Unfortunately I don't use gnome-shell anymore (or gnome for that matter), so I cannot really test this, but the changes seem to make sense so I will approve this anyway.

I am not maintaining this plugin anymore, so if you want I could transfer the ownership to you, or just continue working on your own fork (and I can archive this repo, and link to yours). The second option might be better so we don't end up with broken links. WDYT?

[lumbric]

@tassos thanks for the offer! I'm not sure if I can really take over maintainership at this point. I'll contact you again if I decide that I will continue working on the plugin.