b0bebd6265
Blend files with compositor node trees saves in 4.2 do not work in older version. This is because 4.2 removed the chunk size property of the node tree, so it is set to zero, which is invalid in older versions. To fix this, we add it again as a deprecated DNA member, and set it to default value upon write. Pull Request: https://projects.blender.org/blender/blender/pulls/120246