Symbol conflict with highspy causes segfault when both libraries are loaded

[plancker]

Describe the issue

If tesseract_decoder is imported before import highspy we get a segfault.
This affects anyone using both tesseract_decoder for QEC decoding and highspy/cvxpy for optimization in the same Python session.

What version of the software are you using?

0.1.1.dev20260202233842

How can the issue be reproduced?

# Import tesseract_decoder FIRST
from tesseract_decoder import tesseract  # or: import tesseract_decoder

# Then use cvxpy with HiGHS solver
import cvxpy as cp
import numpy as np

x = cp.Variable(3)
A = np.array([[1.0, 2.0, 3.0]])
b = np.array([6.0])
prob = cp.Problem(cp.Minimize(cp.norm1(x)), [A @ x == b])
prob.solve(solver=cp.HIGHS, verbose=False)  # SEGFAULT (exit code 139)

Note: If the import order is reversed (HiGHS used before importing tesseract_decoder), it works:

# This order works fine
import cvxpy as cp
import numpy as np

x = cp.Variable(3)
prob = cp.Problem(cp.Minimize(cp.norm1(x)), [np.array([[1,2,3]]) @ x == 6])
prob.solve(solver=cp.HIGHS)  # Works

from tesseract_decoder import tesseract # Now safe to import

Environment

• tesseract_decoder: 0.1.1.dev20260202233842 (latest as of Feb 2026)
• highspy: 1.12.0
• cvxpy: 1.6.0
• Platform: macOS 15.3 ARM64 (Apple Silicon)
• Python: 3.13