Bug#1093335: gtk4: FTBFS and autopkgtest failure: test regressions with libpng 1.6.45

[Alessandro Astone]

On Mon, 20 Jan 2025 10:55:15 +0100 Gianfranco Costamagna 
<locutusofborg at debian.org> wrote:
 > Hello, looks like this change was intended.
 > gtk people looks already fixing the test, maybe we can ignore them 
for now?
 >
 > G.
 >
 >

The libpng change is intended, but it doesn't only breaks tests: it 
really does break GTK.

The nodeparser reftests can actually be ignored, because the only 
difference is a re-ordering of the PNG metadata chunks.

But the colorspace test failing shows a real issue: deserialization is 
now broken. Simon already analyzed that pretty well:
 > GDK writes out srgb-linear and [...] with 1.6.45, the colour state 
that is read back
appears to be plain srgb

I've now submitted a patch upstream: 
https://gitlab.gnome.org/GNOME/gtk/-/merge_requests/8158