cbcbox macOS libraries are killed on load

[ghackebeil]

@h-g-s: I'm requesting a fix in your cbcbox repo, but I can't open a pull request or issue against it due to it being a fork, so I'm doing that here.

I've only verified this behavior on on macOS 26.7 (arm64), but it seems that cbcbox 2.935 dies as soon as its bundled OpenBLAS is loaded:

python -c 'import cbcbox, ctypes, os; ctypes.CDLL(os.path.join(cbcbox.cbc_lib_dir(), "libopenblas.0.dylib"))'

Exit 137, no traceback. Model(solver_name="CBC") dies the same way, because libCbc.dylib pulls that library in.

The problem seems to be that setup.py runs install_name_tool and then strip -x on the bundled binaries. Both invalidate the linker's signature, and nothing re-signs afterwards. codesign -dv on the shipped library reports flags=0x20002(adhoc,linker-signed).

Signing after both steps seems to fix the issue:

codesign --force --sign - <path>

The signature then becomes flags=0x2(adhoc), and the library loads.

Here's a patch to setup.py: ghackebeil/cbcbox@39243b2

[h-g-s]

@ghackebeil Thanks for the report and the patch! A couple of things:

1. Issues/PRs on h-g-s/cbcbox are now open. The repo had "Issues" disabled (a fork setting), which is likely what blocked you — that's fixed now. Pull requests were never actually restricted by GitHub for a public fork, so you (or anyone) can open PRs there directly going forward.
2. Your fix has been applied: fix: ad-hoc re-sign macOS binaries after install_name_tool/strip h-g-s/cbcbox#1 — it adds ad-hoc re-signing (codesign --force --sign -) of every bundled Mach-O binary/dylib after install_name_tool/strip, matching your patch at ghackebeil/cbcbox@39243b2c.

I don't have macOS hardware to reproduce/verify locally, so I'd really appreciate it if you could test PR #1 (or the fix-macos-codesign branch) on your macOS 26.7 arm64 machine once CI builds a wheel, to confirm it resolves the SIGKILL you saw. Thanks again for tracking this down!

[ghackebeil]

Awesome, thanks! Yes I’ll try to test out a wheel from your build shortly.