IPython autoreload changes in subdirectory

Question

I launch IPython from the main folder /project. Now if I make changes in the file /project/tests/some_module.py, the changes fail to be autoreloade

Answer 1

Module /project/tests/some_module.py must be importable from /project. It means /project/tests must be in sys.path.

Either change to /project/tests and %run use_some_module.py or do sys.path.insert(0,tests) to insert tests into module search path.

If some_module is not in search path, IPython's autoreload never gonna find it.

Another way to make it work is to make the tests a package by creating __init__.py in it. And use relative import in use_some_module as from .some_module import hello_world. Now do these from IPython prompt,

In [1]: load_ext autoreload

In [2]: %autoreload 2

In [3]: from tests import some_module

In [4]: run -m tests.use_some_module
Hello World!!!
In [5]: ed tests/some_module.py
"tests/some_module.py" 3L, 69C written
 done. Executing edited code...
In [6]: run -m tests.use_some_module
Hello World!!!
Hello World!!!  

That's you have to run use_some_module module in the tests package as a script.

The first time you do %run tests/use_some_module.py, which is run as if you were running python tests/use_some_module.py. So /project/tests which the script is in, is automatically included in sys.path. That's why from some_module import hello_world in use_some_module succeeds. Additionally, after the run, objects in use_some_module's global namespace are available in IPython session.

But when you change tests/some_module, it has to be loaded again to see the changes. To reload it manually, it has to be imported first. Now import should succeed because use_some_module imported it first when it was run, some_module is in sys.modules. But reload to succeed, some_moudle has to be in search path. So, even manual reload would fail let alone autoreload.

In [2]: #before %run  
In [3]: 'some_module' in globals()
Out[3]: False

In [6]: 'some_module' in sys.modules
Out[6]: False

In [7]: 'hello_world' in globals()
Out[7]: False

In [8]: run tests/use_some_module.py
Hello World!!!

In [9]: 'some_module' in globals()
Out[9]: False

In [11]: 'some_module' in sys.modules
Out[11]: True

In [12]: 'hello_world' in globals()
Out[12]: True
In [13]: import some_module

In [14]: some_module = reload(some_module)
---------------------------------------------------------------------------
ImportError                               Traceback (most recent call last)
 in ()
----> 1 some_module = reload(some_module)

ImportError: No module named some_module

Another solution is to start IPython as PYTHONPATH=tests ipython to include tests directory in sys.path.
Or set this c.InteractiveShellApp.exec_lines = ['import sys','sys.path.insert(0,"tests")'] in ipython_config.py.
.