python path-to-your-sandbox/scripts/scons.py

If you run this setup, then whenever the virtualenv is activated, the command scons will just work to run your development version.

$ python -m venv devenv
$ source devenv/bin/activate
$ cd path-to-your-sandbox
$ pip install --editable .

Put these lines in a shell script and run the script. If you want to run it regularly, make the script executable and put it in your private bin directory.

#!/usr/bin/env bash 
SCONS_LIB_DIR=/path_to_scons/SCons
export SCONS_LIB_DIR
exec python /path_to_scons/SCons/scons.py "$@"

You can also run from a checked-out SCons source dir using bootstrap.py, which takes the same args as SCons. That should always use the SCons engine from where bootstrap.py is found.

python /path_to_scons_src/bootstrap.py .

If you run the commands by hand, don't include the "exec" in the final line.

scons --debug=pdb <args...>
b SCons/Tool/msvc.py:158  # to stop at that file:line, looks for file in sys.path e.g. your SCONS_LIB_DIR

Laurent Marchelli:

I use Eclipse PyDev visual debugger rather than pdb, it works to dig into scons and for debugging my SConscript even on my bitbucket fork PyDev environment : SCONS_LIB_DIR=C:\dev\scons\scons-morpheus\src\engine).

For debugging test scripts (launched by runtest.py), this solution has to get extended somewhat:

Because runtest.py launches another process to execute the test, the pydev debugger is not enough, the pydev remote debugger must be used.

Solution in 5 steps:

1. Into your debug configuration's environment variables, add the PYTHONPATH to the pydevd.py script. (Pydev Remote debugger)
2. Add following line at the top of your test script (e.g. msvsTests.py) * import pydevd; pydevd.settrace()
3. Launch PyDev Debug Server.
4. Launch the debugger on runtest.py, the remote debugger will handle the break into your test script.
5. Enjoy ;-)