Crash : Deletion Of Group Output Node of a Nodegroup Connected to Displacement Socket
Closed, ResolvedPublic

Description

System Information
Ubuntu 16.04 64 bits Nvidia Titan Black

Blender Version
Broken: 2.79 and master f34e03d
Worked: (optional)

Short description of error
When 3D View uses Material viewport shading type, if a Group Output node of a nodegroup that is connected to Displacement socket of Material Output node is deleted : Blender crashes.
It does not happen if viewport shading type is different or if connection to Displacement socket is undone.

Bug reported on iirc and blender.stackexchange
https://blender.stackexchange.com/questions/94739/blender-crashes-when-i-want-to-change-the-layer?noredirect=1#comment167350_94739

Exact steps for others to reproduce the error
In attached .blend file, delete Group Output node.

I can confirm this with Windows .2.79

Does not generate anything when used with blender > crashtest.txt

I'm getting this in the debugger.

The thread 0x3ed8 has exited with code 0 (0x0).
The thread 0x4300 has exited with code 0 (0x0).
Exception thrown: read access violation.
node was nullptr.