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Blender will not start if referencing bpy.context.scene.render.fps with expression in startup file
Needs Triage, NormalPublic

Description

System Information
Operating system: Windows-10-10.0.19041-SP0 64 Bits
Graphics card: NVIDIA GeForce GTX 1060 6GB/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 466.63

Blender Version
Broken: version: 2.93.0 Beta, branch: master, commit date: 2021-05-19 16:30, hash: rB0456223cde98
Worked: Unsure if ever worked

Short description of error
Saving the startup file with an expression referencing bpy.context.scene.render.fps disallows Blender to start. If it's not the startup file, the .blend file can be loaded just fine. Tested with the shader editor only, as well as only that attribute. Other drivers or attributes referenced may potentially reproduce the behavior.

Exact steps for others to reproduce the error

  1. Start Blender
  2. Create new material
  3. Enter shader editor for material
  4. Create a new node (in this case we'll make a Value)
  5. Drive the value via the expression #frame/bpy.context.scene.render.fps
  6. Save Startup File
  7. Restart Blender
  8. Blender won't start
  9. Blender won't even start if you try to load a .blend directly
  10. Delete startup file
  11. Blender will start

Extra Notes
After frustratingly trying to figure out what was causing my Blender to crash on startup, I did not test other variables. I would assume that referencing anything in bpy.context.scene would cause the issue, but I'm not sure. The #frame may not be necessary in the example above, but that was my exact input to make the startup fail.


Event Timeline

2.93.0 Beta, branch: master, commit date: 2021-05-19 16:30, hash: rB0456223cde98

Thanks for the report.

Not tested yet but is the case same for 2.93.0LTS? Can you check with that? (https://www.blender.org/download/releases/2-93/)

Also if crash reappears in 2.93.0 then make sure to attach crash logs (refer: https://docs.blender.org/manual/en/latest/troubleshooting/crash.html)

Sure thing. Problem also occurs for 2.93.0 LTS.
I've attached crash file as well as a .blend file that should be okay to open normally, but cause the crash if set as startup file.

Also, no crash log for this one, but I can confirm that this occurs on the 3.0.0 Alpha, cycles-x branch, hash: 94caae981738