fix: Prevent crash on free when RBS is not last node (#600)

`NOTIFICATION_PREDELETE` runs in reverse order, so if RBS is located in
the scene tree _before_ any rollback-managed node, RBS will try to
deregister a node that has been already freed.

The solution was to deregister nodes in `_exit_tree()`, if the
synchronizer's root node is queued for deletion.

Fixes #595

Author: elementbound

addons/netfox.extras/plugin.cfg

@@ -3,5 +3,5 @@
 name="netfox.extras"
 description="Game-specific utilities for Netfox"
 author="Tamas Galffy and contributors"
-version="1.43.4"
+version="1.43.5"
 script="netfox-extras.gd"

addons/netfox.internals/plugin.cfg

@@ -3,5 +3,5 @@
 name="netfox.internals"
 description="Shared internals for netfox addons"
 author="Tamas Galffy and contributors"
-version="1.43.4"
+version="1.43.5"
 script="plugin.gd"

addons/netfox.noray/plugin.cfg

@@ -3,5 +3,5 @@
 name="netfox.noray"
 description="Bulletproof your connectivity with noray integration for netfox"
 author="Tamas Galffy and contributors"
-version="1.43.4"
+version="1.43.5"
 script="netfox-noray.gd"

addons/netfox/plugin.cfg

@@ -3,5 +3,5 @@
 name="netfox"
 description="Shared internals for netfox addons"
 author="Tamas Galffy and contributors"
-version="1.43.4"
+version="1.43.5"
 script="netfox.gd"

addons/netfox/rollback/predictive-synchronizer.gd

@@ -116,6 +116,14 @@ func _enter_tree() -> void:
 func _exit_tree() -> void:
 	_managed_roots.erase(root)
 
+	if root.is_queued_for_deletion():
+		for node in _sim_nodes:
+			RollbackSimulationServer.deregister_node(node)
+		for node in _liveness_nodes:
+			RollbackLivenessServer.deregister(node)
+		for subject in _state_properties.get_subjects():
+			NetworkHistoryServer.deregister(subject)
+
 func _reprocess_settings() -> void:
 	if not _properties_dirty or Engine.is_editor_hint():
 		return
@@ -140,13 +148,6 @@ func add_state(node: Variant, property: String):
 func _notification(what: int) -> void:
 	if what == NOTIFICATION_EDITOR_PRE_SAVE:
 		update_configuration_warnings()
-	if what == NOTIFICATION_PREDELETE:
-		for node in _sim_nodes:
-			RollbackSimulationServer.deregister_node(node)
-		for node in _liveness_nodes:
-			RollbackLivenessServer.deregister(node)
-		for subject in _state_properties.get_subjects():
-			NetworkHistoryServer.deregister(subject)
 
 func _get_configuration_warnings() -> PackedStringArray:
 	if not root:

addons/netfox/rollback/rollback-synchronizer.gd

@@ -330,15 +330,6 @@ func _ready() -> void:
 func _notification(what: int) -> void:
 	if what == NOTIFICATION_EDITOR_PRE_SAVE:
 		update_configuration_warnings()
-	elif what == NOTIFICATION_PREDELETE:
-		for node in _sim_nodes + _state_properties.get_subjects() + _input_properties.get_subjects():
-			RollbackSimulationServer.deregister_node(node)
-			NetworkSynchronizationServer.deregister(node)
-			NetworkIdentityServer.deregister_node(node)
-			NetworkHistoryServer.deregister(node)
-
-		for node in _liveness_nodes:
-			RollbackLivenessServer.deregister(node)
 
 func _get_configuration_warnings() -> PackedStringArray:
 	if not root:
@@ -381,6 +372,17 @@ func _enter_tree() -> void:
 func _exit_tree() -> void:
 	_managed_roots.erase(root)
 
+	if root.is_queued_for_deletion():
+		# RBS and its nodes are being freed, time to deregister everything
+		for node in _sim_nodes + _state_properties.get_subjects() + _input_properties.get_subjects():
+			RollbackSimulationServer.deregister_node(node)
+			NetworkSynchronizationServer.deregister(node)
+			NetworkIdentityServer.deregister_node(node)
+			NetworkHistoryServer.deregister(node)
+
+		for node in _liveness_nodes:
+			RollbackLivenessServer.deregister(node)
+
 func _reprocess_settings() -> void:
 	if not _properties_dirty or Engine.is_editor_hint():
 		return

addons/netfox/state-synchronizer.gd

@@ -130,11 +130,6 @@ func clear_schema() -> void:
 func _notification(what) -> void:
 	if what == NOTIFICATION_EDITOR_PRE_SAVE:
 		update_configuration_warnings()
-	elif what == NOTIFICATION_PREDELETE:
-		for node in _properties.get_subjects():
-			NetworkSynchronizationServer.deregister(node)
-			NetworkHistoryServer.deregister(node)
-			NetworkIdentityServer.deregister_node(node)
 
 func _get_configuration_warnings() -> PackedStringArray:
 	if not root:
@@ -160,6 +155,13 @@ func _enter_tree() -> void:
 
 	process_settings.call_deferred()
 
+func _exit_tree() -> void:
+	if root.is_queued_for_deletion():
+		for node in _properties.get_subjects():
+			NetworkSynchronizationServer.deregister(node)
+			NetworkHistoryServer.deregister(node)
+			NetworkIdentityServer.deregister_node(node)
+
 func _ready():
 	# Reprocess authority
 	# Important if nodes are pre-placed in the scene - node starts as owned by