NodeTree.links.new() can connect one output to a multi-input many times; access violation occurs when disconnecting #89416

New Issue

Fen · 2021-06-24T20:07:25+02:00

Fen commented

2021-06-24 20:07:25 +02:00

System Information
Operating system: Windows-10-10.0.19041-SP0 64 Bits
Graphics card: GeForce GTX 1080/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 446.14

Blender Version
Broken: version: 2.93.1, branch: master, commit date: 2021-06-22 05:57, hash: 1b8d33b18c
Worked: Latest 3.0.0 alpha does not crash or have visual problems.

Short description of error
Nodes can be linked via Python script by using NodeTree.links.new(input, output). If this is done repeatedly, the same socket can be connected many times, resulting in a visual bug. Trying to disconnect one of these noodles results in an access violation.

Exact steps for others to reproduce the error

Open the attached file
Try to disconnect one of the wires by grabbing on the multi-input socket
Crash

multi-link-crash.blend

To cause the problem:

Run the Python script. It creates a Join node and a Cube node, then links them together five times.

Stack trace: P2211

This bug is completely gone in 3.0.0: only one link is produced. If you set up the glitch in 2.93.1 and load the .blend in 3.0.0, the visual bug is gone, and the noodles can be safely unplugged.

So, this will become moot once 3.0 is out, but it's still a (minor) problem in the current release.

**System Information** Operating system: Windows-10-10.0.19041-SP0 64 Bits Graphics card: GeForce GTX 1080/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 446.14 **Blender Version** Broken: version: 2.93.1, branch: master, commit date: 2021-06-22 05:57, hash: `1b8d33b18c` Worked: Latest 3.0.0 alpha does *not* crash or have visual problems. **Short description of error** Nodes can be linked via Python script by using `NodeTree.links.new(input, output)`. If this is done repeatedly, the same socket can be connected many times, resulting in a visual bug. Trying to disconnect one of these noodles results in an access violation. ![image.png](https://archive.blender.org/developer/F10194843/image.png) **Exact steps for others to reproduce the error** 1. Open the attached file 2. Try to disconnect one of the wires by grabbing on the multi-input socket 3. Crash [multi-link-crash.blend](https://archive.blender.org/developer/F10194849/multi-link-crash.blend) To cause the problem: 1. Run the Python script. It creates a Join node and a Cube node, then links them together five times. Stack trace: [P2211](https://archive.blender.org/developer/P2211.txt) This bug is completely gone in 3.0.0: only one link is produced. If you set up the glitch in 2.93.1 and load the .blend in 3.0.0, the visual bug is gone, and the noodles can be safely unplugged. So, this will become moot once 3.0 is out, but it's still a (minor) problem in the current release.

Fen commented

2021-06-24 20:07:25 +02:00

Added subscriber: @chemicalcrux