Add a console/REPL/expression evaluator for debugging GDScript

[severin-lemaignan]

Describe the project you are working on:

Several game dev (!)

Describe the problem or limitation you are having in your project:

[issue imported from https://github.com/godotengine/godot/issues/7057]

Debugging gdscript is difficult without being able to quickly inspect and/or manipulate variables. Many platforms/language have a tool to open an interactive console at arbitrary points, and inspect & execute code (from pdb.set_trace in python to the javascript console found in Firefox/Chrome dev tools).

Describe the feature / enhancement and how it helps to overcome the problem or limitation:

When debugging a game, the debugger panel should feature an additional sub panel or tab with an interactive console where gdscript command could be entered and executed.
The scope should be matching the local scope where the code has been interrupted (via a breakpoint or an exception).

Describe how your proposal will work, with code, pseudocode, mockups, and/or diagrams:

See above.

If this enhancement will not be used often, can it be worked around with a few lines of script?:

No.

Is there a reason why this should be core and not an add-on in the asset library?:

This would form a key part of the debugging toolset.

[Calinou]

See godotengine/godot#26219 where this feature was implemented, but it wasn't merged. Note that GDScript will be rewritten from scratch in Godot 4.0, so the PR will likely have to be (mostly) remade from scratch.

[severin-lemaignan]

Ok! Closing then!

[Calinou]

You could leave this proposal open - I think the feature is still relevant.

[Calinou]

Closing in favor of #4473, which was created following an implementation of the feature.