Prevent Sync blocking if added after the parent node

[Ivan-267]

The main supported method for using the sync node currently is to add it initially to the training scene.

However, if you add the sync node later (e.g. in code) after you've initialized the scene, its ready method will not complete.

This should address that specific scenario without altering functionality otherwise (note: yet to be tested).

There is a related issue here: #55

[stefanfausser]

Allowing to dynamically add a sync node is a very good idea.

I have not tested this but have had a look at the code:

Following line is removed:
await get_parent().ready

and then replaced by these lines:

var parent := get_parent()
if not parent.is_node_ready():
    await parent.ready

However isn't this the same as:

var parent := get_parent()
await parent.ready

Because await parent.ready is not waiting when the parent node is already ready?

I only see a difference between the original line and the replaced lines, when await.parent.ready is waiting even when the parent node is ready.

Maybe the code is doing something else I am not currently seeing?

[Ivan-267]

If the parent node is already ready, that means the ready signal was already emitted as well.

In the standard use setup that's fine, sync's ready will be called before the parent is ready, and the await is used to allow the scene to load (so that we have available aicontrollers).

However, if you were to add the sync node after, then its ready method would be awaiting a signal that will not be sent again.

[stefanfausser]

Thanks, that explains it. So without the if-condition, the sync node would wait forever for the ready Signal that will not be emitted again because the parent node already is ready.

[Ivan-267]

Thanks, that explains it. So without the if-condition, the sync node would wait forever for the ready Signal that will not be emitted again because the parent node already is ready.

That's correct. It's fine for the standard use case as in the examples, this just adds the option of adding the sync node later.