Scene-item private_settings?

[MarioMey]

This cheatsheet has Read and write private data from scripts or plugins part. I didn't tried it, but by reading the code, it writes to private_settings... of what? Of OBS itself?

Every source and item has a "private_settings": {},as item in JSON. Can't we put data inside it as value of that item?

[upgradeQ]

I suggest you to try it, it's basically a shared memory interface (global namespace) for LuaJIT, Python, and C/C++ plugins .
There is a link which lists all methods available in obspython namespace, you could Ctrl+F a word "private" to see how it's used internally in OBS Studio, e.g this is how OBS knows that it should collapse or not a group, which reflects in scene_collection_name.json has this section "private_settings": { "collapsed": true},

[MarioMey]

Oh, there is a obs_sceneitem_get_private_settings! I had looked for it and I didn't found it.

But... where is obs_sceneitem_set_private_settings? 🤔

[MarioMey]

I found where group is collapsed and it would save that state (here)... but, as I don't understand C++, I don't understand this code:

void SourceTreeItem::ExpandClicked(bool checked)
{
	OBSData data = obs_sceneitem_get_private_settings(sceneitem);
	obs_data_release(data);

	obs_data_set_bool(data, "collapsed", checked);

	if (!checked)
		tree->GetStm()->ExpandGroup(sceneitem);
	else
		tree->GetStm()->CollapseGroup(sceneitem);
}

Why does it create data object... and it realeases it inmediatly? Then, it set collapsed setting to that data object... but when does that data is set to sceneitem?

[upgradeQ]

I guess it's one-line C++ equivalent to Python context managers, here is more illustrative example without auto release magic.

[upgradeQ]

Then, it set collapsed setting to that data object... but when does that data is set to sceneitem?

I think it's used for initialization and saving state. There is no bindings to change that while runtime, this is not exposed to python also.