System Information
Mac OS X Yosemite 10.10.3 running on
MacBookPro8,3 with AMD Radeon HD 6750M 1024 MB VRAM (16 GB system RAM)
Blender Version
Blender 2.75-RC2
Short description of error
Blender (UI) Hangs (Beach ball/Hour glass cursor)
Exact steps for others to reproduce the error
Can confirm that here... Main thread goes up to 100%. Reason could be that there are 30 other node groups in the tree :S
Yeh... I know I'm twisting the blender node system in knots a bit with some of this stuff... I hope to add some node types eventually to make these kind of operations easier. Julian, Thank you for confirming this on another machine.
I can redo this with a 2.74 build (the arch linux package), but not in my own builds - master or 2.75rc2 (debug or release builds).
I can redo.
version 2.75 (sub 1), branch b'master', commit date b'2015-06-29' b'21:10', hash b'56ca7f3', b'Release'
@Campbell Barton (campbellbarton), guess that's because you're building without Cycles? :)
The node setup is quite insane here and current dependency builder in Cycles actually has exponential complexity depending on the shader graph layout, which is quite a case here. This is in a TODO to make shader graph compilation more robust, so would not consider it a bug. Also, you shouldn't really use such setups for shaders anyway, this is something what we've got OSL for.