Critical Error under Python 3.10+ / Windows (in Spyder context)

[roberthuebener]

Describe the bug
Using Python version higher than 3.10, there is a critical error which causes, e.g., Spyder kernels to crash immediately on import of cvxpy under Windows 11. Under Windows 10, runtime errors concerning the numerics occur instead. The problems disappear under Python 3.10 and earlier using an otherwise identical environment and code.

To Reproduce
Use Windows 11, Python 3.14, cvxpy 1.8.2 and Spyder 6.14. Import cvxpy in a Spyder notebook. The Spyder kernel crashes immediately.

Expected behavior
No crash on import.

Output
No stack trace can be provided, as there is no output or stack trace whatsoever.

Version

• OS: Windows 11
• CVXPY Version: 1.8.2
• Spyder Version: 6.1.4
• Python Version 3.14

Additional context
Although this seems to be a Spyder-related problem, it might have deeper roots because the error depends on the version of Python and is related to numerical errors.

The most direct crash happens under Windows 11 using Spyder of any version and importing any version of cvxpy. Corruptions of cvxpy happen also under Windows 10, Python>3.10, but they do not cause a crash on import but error messages during runtime hinting at problems with the underlying numerics libraries. The crashes and errors do not appear for Python 3.10 and earlier. The version of cvxpy does not seem to matter. The problem does not seem to occur using Python on the command line or ipython, but since the problem is subtle at least under Windows 10, it could exist also in these contexts.

[PTNobel]

I have never heard of Spyder; do you have any sense of what it does differently from normal Python?

[roberthuebener]

Spyder (www.spyder-ide.org) is simply a front end to Python. It sits on top of iPython with customized configuration scripts. The reason why I brought it up is that a combination of Python and Spyder's scripts triggers the cvxpy error reliably when importing cvxpy (and it is not so easy to trigger it in another way).

However, because of the dependency on the Python version and the Windows version, I suspect there is something going on deeper than Spyder and its scripts. It is also possible that the problem lies in the concrete distributed cvxpy module that you get using pip install. For example, the cvxpy runtime warnings coming up under Windows 10 (instead of the immediate crash during import under WIndows 11) possibly hint at some conflict with libraries, linking or bounds checking. Unfortunately, as a mere user, I do not make progress with my own investigations into the matter anymore. Hence the ticket.

Using MacOS on intel, there is no problem even with Python 3.14, by the way.

[PTNobel]

Can you share the warnings you see on Windows 10?

[roberthuebener]

Sorry, no. Windows 10 is gone. It was a convergence warning or similar, and it did not appear deterministically even with fixed warm start. The numerical results were correct, though. Under W11, the warnings do not appear anymore, even with the very same code.

[PTNobel]

Ah okay. Thank you; I'll try to investigate