Hi Mark, All,
Following up on my earlier thread about axdebug being disabled on Python
3.11+ ("Debugging extensions (axdebug) module does not exist").
I've tracked down the root cause and submitted a fix:
https://github.com/mhammond/pywin32/pull/2723
The error message comes from framework.py line 763 — when SetScriptSite
creates the DebugManager, it tries to import axdebug. If axdebug.pyd
doesn't exist (because the build was skipped on 3.11+), the ImportError
is caught and debugging is silently disabled.
Root cause:
Python 3.11 (PEP 523) made PyFrameObject an opaque type :
- C extensions can no longer access struct fields like
frame->f_code, frame->f_back, or frame->f_trace directly.
- AXDebug.cpp's SetThreadStateTrace() relied on direct struct
access to walk the frame chain and set trace functions, so it failed to
compile on 3.11+.
- PyWin32: The module was disabled in setup.py as a workaround.
The fix replaces direct struct access with the official getter APIs that
Python provides for opaque frame access:
frame->f_code -> PyFrame_GetCode(frame)
frame->f_back -> PyFrame_GetBack(frame)
frame->f_trace = fn -> PyObject_SetAttrString(frame, "f_trace",
fn)
state->frame -> PyThreadState_GetFrame(state)
These APIs are stable across Python 3.11-3.14. The pre-3.11 code path is
preserved with #if guards, so older Python versions are unaffected.
This PR also fixed a long-standing bug in adb.py where step-over (F10)
would not stop after returning from a function — dispatch_return now
promotes stopframe to the caller frame.
Minimal change — 3 files, +33/-20 lines. Tested on Python 3.14.2 with a
custom ActiveX Script Host exercising the full debug path. I also built
a DAP (Debug Adapter Protocol) bridge that enables VS Code to debug
ActiveX-hosted Python scripts — breakpoints, step-into, step-over,
step-out, variable inspection, and watch expressions all work correctly
through the fixed axdebug module.
Would appreciate your review when you get a chance.
Best,
Wuping
------ Original Message ------
From "Wuping Xin" <[email protected]>
To "Mark Hammond" <[email protected]>; "[email protected]"
<[email protected]>
Date 3/3/2025 11:07:06 AM
Subject Re[2]: [python-win32] Python Active Scripting Debug
Thank you Mark for the response. Appreciate your input.
Best
Wuping
------ Original Message ------
From "Mark Hammond" <[email protected]>
To "Wuping Xin" <[email protected]>; "[email protected]"
<[email protected]>
Date 3/3/2025 10:24:18 AM
Subject Re: [python-win32] Python Active Scripting Debug
It has been quite a few years since anyone worked on that, but in
general it should "just work" if everything is registered correctly.
There are a few demos which should make OK starting points, and
ensuring everything is registered for debugging, and debugging output
can be seen (typically via win32traceutil) must be done.
Unfortunately, I'm not aware of anyone trying to use the VS tools in
this way.
Good luck,
Mark
On 2025-02-28 8:54 p.m., Wuping Xin via python-win32 wrote:
Hi All,
I am trying to debug Python Active Scripting, using Visual Studio. I
am 100% sure it should work but I just cannot get it work.
I've installed the debug symbols of the Python version, and installed
Visual Studio Python Native Development tools.
I also set the "Debugging" registry entry for the ActivePy from 0 to
1.
I am able to attach the Python script to the PythonActiveScript host.
But, I just got the following message:
Debugging extensions (axdebug) module does not exist - debugging is
disabled..
Any insights?
Thank you in advance!
W.X.
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