pdb - Launch Python debugger while simultaneously executing module as script

Question

When developing a Python package, it's very convenient to use the -m option to run modules inside the package as scripts for quick testing. For example, for somepackage with module somemodule.py inside it, invoking

python -m somepackage.somemodule

from the directory where somepackage resides will run somemodule.py as though the submodule were __main__. Using this calling syntax is especially important if the package is using explicit relative imports as described here.

Similarly, it is also convenient to use the -m option to debug a script, as in

python -m pdb somescript.py

Is there any way to do both at the same time? That is, can I call a module as though it were a script and simultaneously launch into the debugger? I realize I can go into the code itself and insert import pdb; pdb.set_trace() where I want to break, but I'm trying to avoid that.

Answer 1

There are efforts underway to solve this in Python itself. Looks like with Python 3.7, you can do:

python -m pdb -m somepackage.somemodule

And I've provided a backport for older Python versions (2.7+):

pip install backports.pdb
python -m backports.pdb -m somepackage.somemodule