The GTK+ 3 port of Meld was developed against 3.8, targetting 3.6. When I started doing the port, 3.8 was what was available in current distributions, so it seemed reasonable to expect that by the time the port was done, many users would have access to it. In fact, it took way longer than I’d hoped and the GTK+ 3 port was released at about the same time as GTK+ 3.14 came out, which then broke everything.
Drawing in GtkTextView and GtkSourceView changed to use a new API involved drawing of layers, and changed how the background was drawn. The new API is actually really nice and will be great to use, but…
…well, it broke everything. The custom painting that Meld does all over the textview was broken, and because the background clearing was a theme-specific change, it broke differently in different themes.
Oh, and don’t worry! All of this was completely unannounced. I found out about the layer drawing by reading a random blog post after the release of 3.14 mentioning that it might be useful for another application. It will be too… one day.
Images in dialogs
Dialogs used to be guaranteed to have an image if a message-type was set. This is no longer the case, so any code that assumed that there was going to be an image there just breaks. Good job!
This broke lots of random dialogs in Meld, and prevented people from doing things like… saving files.
Dialogs in general
Spacing, padding and outline drawing have all changed, so all our dialogs now look awful. They’ll have to be adjusted to look okay with GTK+ 3.14 which will, by extension, make them look awful with everything pre-3.14.
Size calculation changes
In 3.10, the way GtkBox expand properties propagate changed. Now granted, it was weirdly broken before, but this behaviour change made a couple of bits of Meld’s preferences dialog unusable.
Life as a GTK+ app developer
When Meld 3.12 was released, my plan was to get a really quick 3.14 release done and out, and try for another quick release to sync up Meld and GNOME on 3.16. Instead, I’ve spent most of my very limited spare time plugging holes in various regressions.
Accusations that level X of a technology stack doesn’t really understand what it’s like for level Y of the technology stack aren’t exactly new. Some vocal members of the community will complain about this in any stack, and GTK+ is no different. However, this is the first release cycle that I’ve spent hours actively cursing breakages in the GTK+ stack. I hope it’s a blip.