Add "Set as Main Scene" to EditorSceneTabs context menu

[altamkp]

Implementation of the following feature request: godotengine/godot-proposals#10587

• Bugsquad edit, closes: Add "Set as Main Scene" to EditorSceneTabs context menu godot-proposals#10587

[vaner-org]

I'd really like to see this feature in-engine. I have a follow up to this commit that adds some additional functionality, to make it more like Play This Scene:

1. If the scene has no root, then the option is greyed out.
2. If the scene is unsaved, the file is saved and then set as main scene.

Unfortunately I worked on it before looking up if there was already a PR for this.

[KoBeWi]

Needs rebase due to conflicts.

If the scene has no root, then the option is greyed out.
If the scene is unsaved, the file is saved and then set as main scene.

I think having no root node is fine if the scene is saved. The current editor state is irrelevant if the file is a valid scene.

[vaner-org]

I think having no root node is fine if the scene is saved. The current editor state is irrelevant if the file is a valid scene.

At the moment it isn't possible to right-click on a scene tab without also making it the currently selected scene in the editor. "Play This Scene" also currently relies on the current editor state to check if there is no root node, so I was trying to mimic its functionality. Should I fork this to a new PR for the rebase?

[KoBeWi]

"Play This Scene" also currently relies on the current editor state to check if there is no root node

Maybe it's related to the fact that running the project will auto-save scenes? idk, but it could be reconsidered.

[vaner-org]

Seems I misremembered, looked over the code again.
bool no_root_node = !EditorNode::get_editor_data().get_edited_scene_root(tab_id);
So it does consider the currently selected tab's id, and does not reference the current editor state. I think if right-clicking a tab without also setting it as the current tab becomes possible, then this should continue to work as expected. Would be happy to work on that next.

[Repiteo]

Superseded by #107652