Code autoreload support

[mandx]

Code autoreload support: Basically what Django's runserver does:

• Watch for code changes (using pyinotify if available, otherwise just keep polling for changes)
• Reloads the webserver process.

Is this possible right now? If not, any plans of implementing this?

In my particular case, my workflow is usually:

• Launch ptpython
• Import some modules
• Instantiate some classes from those modules
• Run the methods I want to test of those classes / Run the functions I want to test (from the imported modules)
• Something doesn't work as expected: Go back to the editor, make some changes. This is when ptpython picks up the changes, and then it would have to re-run this session's history.
• Go back to ptpython's terminal, hit the Up key to re-select the previous line, Enter to execute it.

[jonathanslenders]

Hi @mandx,

Thanks for the feature request and describing your use case. I think there are many more people with the same issue.

It is very tricky. My first thought is to use imp.reload: https://docs.python.org/3/library/imp.html#imp.reload But as the documentation explains, there are many caveats, probably some of them leading to very weird behaviour.

It's different for Django. If I understand correctly, it doesn't use reload, but it actually restarts the whole process. For Django that's easy, because Django processes are stateless. We could call exec/fork, but it's harder for a REPL. You want to have a clean state to begin with, but still the code from the previous session.

So, what I'm probably going to do, is make it easier to select and edit/execute the last 'n' items from the history. I can probably make a nice user interface for that. (I have something in mind.)
And secondly. Find a way to reload the REPL, while maintaining the current input. There are several ways to do that, but I need to find something that works well.

If that works, I think that will be cool, but honestly, it's not my top priority, and it needs some time.

[jonathanslenders]

Hi @mandx,

Reload is not yet implemented. But there is something now that could solve a part of your problem.
Re-executing several lines form the history is now easier.

Try to install the latest version from pip. Press F3 (history) and select your history from there. Does that help? Is it intuitive or not?

Jonathan

[mandx]

Well, actually this is very useful! Just a couple of notes, for the sake of organization, I have put them in a new issue: #70.

[shanechin]

A small bit of this might be handled with https://ipython.org/ipython-doc/dev/config/extensions/autoreload.html. As the documentation mentions, some cases are unhandled, but others work fairly well.