[BUG] Crash on Python 3.12 (Windows) when pyxcp runs under Robot Framework (0xC0000005)

[wolf-gili]

Description

Hi,
We’re seeing a reproducible crash after migrating from Python 3.10 to 3.12 on Windows.
Setup:

• OS: Windows 10
• Python: 3.12.x
• Using pyxcp over ETH/UDP (IPv6)
• Test execution via Robot Framework
  Behavior:
• Running the same XCP flow directly from a normal Python main script works fine.
• Running it from Robot Framework crashes the Python process with:
  • exit code -1073741819 (0xC0000005), Windows access violation
• faulthandler stack trace points into pyxcp:
  • pyxcp.transport.eth (_packet_listen / listen)
  • pyxcp.master.master.connect()
  • pyxcp.transport.base._request_internal()
    Notes:
• This is not a Python exception; it is a hard process crash.
• As a workaround, we moved pyxcp work into a separate spawned process and communicate via queues; this avoids the crash under Robot.
  Question:
• Is this a known compatibility issue with Python 3.12 and/or threaded execution environments like Robot Framework?
• Do you recommend a specific pyxcp version, transport/threading setting, or connect/listener sequence for Python 3.12 on Windows?
• If useful, we can share a minimal reproducer and full faulthandler log.

Transport Layer

Ethernet (UDP)

Category

Transport / Connection

pyxcp Version

0.25.5

Python Version

3.12

Operating System

Windows 10

Installation Method

pip install pyxcp

Steps to Reproduce

1. Use Windows + Python 3.12.x environment.
2. Run our XCP flow with pyxcp over ETH/UDP (IPv6) inside Robot Framework (same flow that works from a normal Python main script).
3. Execute a connection sequence that includes:
   • transport.start_listener()
   • master.connect()
4. During Robot execution, Python crashes with:
   • Process finished with exit code -1073741819 (0xC0000005)
5. faulthandler stack trace points to:
   • pyxcp.transport.eth (_packet_listen, listen)
   • pyxcp.transport.base._request_internal
   • pyxcp.master.master.connect

Expected Behavior

pyxcp should behave the same under Robot Framework as in a normal Python main script:

• no native process crash,
• no access violation (0xC0000005),
• clean connect/status flow or a regular Python exception if connection fails.

Actual Behavior

Under Robot Framework (Windows, Python 3.12), pyxcp crashes the interpreter with:

• Process finished with exit code -1073741819 (0xC0000005)
• Windows fatal exception: access violation
faulthandler points to:
• pyxcp.master.master.connect
• pyxcp.transport.base._request_internal
• pyxcp.transport.eth._packet_listen / listen
  Same flow works from a regular Python main script.
  Current workaround: run pyxcp in a separate spawned process.

Configuration

Additional Logs

Checklist

• I have searched existing issues for duplicates
• I have tested with the latest version of pyxcp
• I can provide a minimal reproducible example

[wolf-gili]

@christoph2

[DanielBzz]

Hey @christoph2 , maybe you have any idea how to solve it?

[christoph2]

@wolf-gili
@DanielBzz

There were strange problems on Linux / Raspberry PI similar to this issue here.
I tracked them down to an ABI mismatch between Python and pybind11.
This is fixed with the lastest commit.