How to re-import an updated package while in Python Interpreter?

Delving into module reloading

When you import a module in Python, it's akin to signing a contract. Without an agreement on change management, Python can't know that the contract (module) has been updated. This is where importlib.reload() comes in.

Dealing with inter-module dependencies

If you have modules that depend on each other like Peanut Butter and Jelly, reloading can turn confusing. In such cases, it's like a dance; you need to reload all related modules in perfect order.

Ensuring object reincarnation

After reloading a module, your old object instances are stuck in the past. They abide by the old class definitions. Thus, they need a bit of urging (or forcing) to re-instantiate with the new definitions.

Leveling up: Advanced reloading techniques

Some modules are trickier to reload than others, especially with larger or more complex projects.

Third-party packages to the rescue

For complex reloading, consider using ready-made packages like reimport, xreload, or livecoding. They are to reloading what a GPS is to a road trip.

Watch out for Extension modules

Reloading extension modules (C, Cython) is a bit like juggling knives — error-prone. With these, better to err on the side of caution and restart the interpreter.

When in doubt, cycle it out

For complex situations, sometimes it's easier to just restart the interpreter. It's the equivalent of the age-old advice - "Have you tried turning it off and on again?".

Going above and beyond with reloading

When it comes to large projects or environments that require live updates, additional measures might need to be implemented.

Refreshing from imports post-reload

To keep your specific object imports up to date, re-run the from import statements. It's like taking a screenshot of your code. Don't forget to hit refresh!

from mymodule import some_function
# Did some wizardry in mymodule.py
importlib.reload(mymodule)
from mymodule import some_function  # Now back to the future
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Unloading from sys.modules

Sometimes, in order to truly start afresh, you might need to unload the module from sys.modules. It's like evicting your module before letting it back in.

import sys
# Evict your module from Python city
del sys.modules['mymodule']
# Now, let it back in with open arms
import mymodule
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References

1. importlib — The implementation of import — Python 3.12.2 documentation — the official Python doctor for reloading modules.
2. Python import: Advanced Techniques and Tips – Real Python — A good read to broaden the horizon of Python's import mechanism.
3. How do I unload (reload) a Python module? - Stack Overflow — where the community shares their reloading battles.
4. Python - Reimport a module while interactive - Stack Overflow — A more interactive approach to module reloading.
5. Python Modules and Packages – An Introduction – Real Python — Python modules for beginners.
6. Structuring Your Project — The Hitchhiker's Guide to Python — A structuring guide for Python projects.
7. python - Reloading submodules in IPython - Stack Overflow — A group discussion on reloading submodules or what I call the Russian Dolls scenario.