Thonny's debug feature "issue"

[villares]

This looks like a really hard thing:
Thonny's debug feature doesn't work with "imported mode" and I was reminded of that by a recent (unrelated) -Processing forum post. I wonder if there is a solution to this or it is just something we might want to warn users about when they try "the bug button".

I think Aivar had commented in a conversation we had, a long time ago, on this being a huge drawback of having a "simplified language mode pre-processing"...

[hx2A]

Right. Since imported mode uses the run_sketch command line tool, any debugging would have to be done through that. I did learn some things about debuggers while at PyCon. It would be very difficult to add debugging or the ability to step through code as a feature in run_sketch.

In module mode, debugging should work just fine but last time I tried that in VSCode it did not work for me. It was a while ago though. Does it work in Thonny?

It might be an interesting educational tool to debug a Sketch using the default renderer and see the Sketch being drawn one line at a time. Does that actually work? With the OpenGL renderers, the code could perhaps work with a debugger but you would not see the Sketch window change until after the draw() function was complete.

[villares]

The Thonny debug in "module mode", was way less useful than what I remembered :(
You see it go through global scope, function definitions and when py5.run_sketch() is called nothing is seen afterwards.

[hx2A]

The Thonny debug in "module mode", was way less useful than what I remembered :( You see it go through global scope, function definitions and when py5.run_sketch() is called nothing is seen afterwards.

For non-py5 Python code it probably works a lot better. Recall that py5 works by making calls from Java to Python. Every execution of draw() is called by Java. So what happens when you run a Sketch is that py5 collects the relevant Sketch functions, sets things up with a Processing Java Sketch, and then launches the Java Sketch. As far as the debugger is concerned, it steps through the code until the call to Processing's runSketch() method but does not see that return. On the Java side it is launching threads and one of those threads makes calls back to Python.

I do believe it would be possible for a debugger to work with py5. I know in VSCode the debugger can work with a Python website which also has a different way of executing Python code. I haven't gotten around to looking at that though.

[villares]

Today I tried a Pdb breakpoint() with module mode in Thonny, just out of curiosity. It might be useful...

(works on imported mode too)

[hx2A]

Neat! It never occurred to me to use breakpoint() in a running Sketch. I just tried it using what I had in front of me, which happens to be a new live coding feature...I didn't think it would work, but it actually worked perfectly. I didn't think the two would cooperate, but it worked great.