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Tips for debugging SCons code and your scripts

To use local scons source rather than installed:

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.

   1 SCONS_LIB_DIR=/path_to_scons/src/engine
   2 export SCONS_LIB_DIR
   3 exec python /path_to_scons/src/script/ .

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

   1 python /path_to_scons_src/ .

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

To run under debugger:

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

Debugging in Eclipse/PyDev

Laurent Marchelli:

I use Eclipse PyDev visual debugger instead than pbd, 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 (, this solution has to get extended somewhat:

Because launch 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 script.(Pydev Remote debugger)
  2. Add following line at the top of your test script (e.g.
    • import pydevd; pydevd.settrace()

  3. Launch PyDev Debug Server.

  4. Launch the debugger on, the remote debugger will handle the break into your test script.
  5. Enjoy ;-)

DebuggingScons (last edited 2014-11-15 10:44:01 by DirkBaechle)