AssertionError with Cython modules (frozenlist._frozenlist) under Python 3.13 in PyDev debugger

[icarocd]

AssertionError with Cython modules (frozenlist._frozenlist) under Python 3.13 in PyDev debugger

Environment

• Python: 3.13.0 (official CPython)
• PyDev.Debugger: 13.0.2 (bundled with Eclipse)
• Eclipse
• OS: Linux (Kubuntu 25.04)
• Relevant C extension: frozenlist._frozenlist (used via aiohttp)

---

Problem

When running code with the debugger enabled in PyDev (Eclipse), I consistently hit this traceback when importing aiohttp, due to its internal use of the frozenlist Cython extension:

AssertionError: <code object _call_with_frames_removed at 0x..., file "<frozen importlib._bootstrap>", line 480> != <code object PyInit__frozenlist at 0x..., file "frozenlist/_frozenlist.pyx", line 1>

The traceback is triggered in: _pydevd_sys_monitoring_cython.pyx, line 607, _get_func_code_info

---

Context

• The speedups were successfully compiled using:

  python3 setup_pydevd_cython.py build_ext --inplace
  

• Still, the debugger crashes when any Cython-compiled module (specifically frozenlist) is imported during debugging.

---

Workaround

I was able to continue by monkey-patching the module like this:

import sys
try:
    import frozenlist._frozenlist
except AssertionError:
    if 'frozenlist._frozenlist' in sys.modules:
        del sys.modules['frozenlist._frozenlist']
    sys.modules['frozenlist._frozenlist'] = None

This avoids triggering PyDev's internal assertion and allows the debugger to proceed, at the cost of reduced performance in aiohttp.

---

Request

Please confirm whether full support for Python 3.13 + Cython extensions is expected in an upcoming PyDev.Debugger version.

Thanks for your great work on this project!