About improving Scene Unique Nodes

[Mickeon]

Since 3.5 has finally been officially released, users can finally test Scene Unique Nodes, before 4.0 comes out.

In a nutshell, any Node within a Scene can be marked as Unique. One can then use the "%" accessor before a Node's name in a NodePath (eg. get_node("%Node") to always point to the same Node, regardless of where it is in the tree).

This is, for example, useful when editing any Scene whose Nodes are prone to be shuffled around the tree, potentially breaking any related code if the paths aren't up to date.

Because of its fresh availability, I thought it'd be a good idea to compile some proposals/pull requests regarding them, to bring light on the issues they plan to resolve, and hear the community's thoughts. I find this to be particularly important, as a few may potentially be compatibility-breaking.

(Most of these entries happen to be mine, as I've taken quite the personal interest for thinking on how to improve this feature. More will be added in the future when I see them):

Proposals

Scripting:

• Add autocompletion for scene unique nodes #4593
• Access Scene Unique Nodes in code with a $$ operator/literal #5064
• Add Node.get_unique_node() as a way to get Scene Unique Nodes #5048
• Use "$" as the Scene Unique Node symbol #4497

UI:

• Improve how Scene Unique Nodes are highlighted in Scene Tree Editor #4494
• Integrate Scene Unique Nodes toggle in Node renaming process #4498

Pull Requests

Scripting

• GDScript: Support % in shorthand for get_node (not in 3.x)