Julian Eisel
2bd9f9d976
This is especially useful when trying to add a node group instance, e.g. via drag & drop from the Outliner or Asset Browser. Previously this would just silently fail, with no information why. This is a source of confusion, e.g. earlier, it took me a moment to realize I was dragging a node group into itself, which failed of course. Blender should always try to help the user with useful error messages. Adds error messages like: "Nesting a node group inside of itself is not allowed", "Not a compositor node tree", etc. Adds a disabled hint return argument to node and node tree polling functions. On error the hint is reported, or could even be shown in advance (e.g. if checked via an operator poll option). Differential Revision: https://developer.blender.org/D10422 Reviewed by: Jacques Lucke