feat: add bounded npc memory retention

tests/simulation_state_serialization_test.gd

@@ -17,6 +17,7 @@ func _run() -> void:
 	_test_previous_world_relationship_migration()
 	_test_previous_world_knowledge_migration()
 	_test_previous_world_provenance_migration()
+	_test_previous_world_retention_migration()
 	_test_relationship_schema_rejection()
 	_test_schema_rejection()
 
@@ -138,6 +139,15 @@ func _test_schema_rejection() -> void:
 	)
 	_check(SimulationStateRecord.from_json("[]") == null, "Non-record JSON should be rejected")
 
+	var manager := _create_manager(41)
+	var invalid_clock_data: Dictionary = manager.create_state_record().to_dictionary()
+	invalid_clock_data["simulation"]["tick_interval"] = 0.0
+	_check(
+		SimulationStateRecord.from_dictionary(invalid_clock_data) == null,
+		"Saved simulation clocks with a zero tick interval should be rejected"
+	)
+	manager.free()
+
 
 func _test_legacy_resource_migration() -> void:
 	var migrated := ResourceStateRecord.from_dictionary(
@@ -272,7 +282,7 @@ func _test_previous_world_knowledge_migration() -> void:
 	var deposit_event := EconomicEventRecord.create(
 		0,
 		SimulationIds.EVENT_STORAGE_DEPOSITED,
-		12,
+		0,
 		1,
 		SimulationIds.npc_inventory_id(1),
 		SimulationIds.STORAGE_VILLAGE_PANTRY,
@@ -305,11 +315,11 @@ func _test_previous_world_knowledge_migration() -> void:
 func _test_previous_world_provenance_migration() -> void:
 	var manager := _create_manager(60)
 	var previous_data: Dictionary = manager.create_state_record().to_dictionary()
-	previous_data["schema_version"] = SimulationStateRecord.PREVIOUS_SCHEMA_VERSION
+	previous_data["schema_version"] = SimulationStateRecord.PROVENANCE_LEGACY_SCHEMA_VERSION
 	var deposit_event := EconomicEventRecord.create(
 		0,
 		SimulationIds.EVENT_STORAGE_DEPOSITED,
-		12,
+		0,
 		1,
 		SimulationIds.npc_inventory_id(1),
 		SimulationIds.STORAGE_VILLAGE_PANTRY,
@@ -358,6 +368,77 @@ func _test_previous_world_provenance_migration() -> void:
 	manager.free()
 
 
+func _test_previous_world_retention_migration() -> void:
+	var manager := _create_manager(61)
+	var previous_data: Dictionary = manager.create_state_record().to_dictionary()
+	previous_data["schema_version"] = SimulationStateRecord.PREVIOUS_SCHEMA_VERSION
+	previous_data["simulation"]["tick_count"] = 50
+	var deposit_event := EconomicEventRecord.create(
+		0,
+		SimulationIds.EVENT_STORAGE_DEPOSITED,
+		0,
+		0,
+		SimulationIds.npc_inventory_id(0),
+		SimulationIds.STORAGE_VILLAGE_PANTRY,
+		SimulationIds.RESOURCE_FOOD,
+		2.0
+	)
+	previous_data["economic_events"] = [deposit_event.to_dictionary()]
+	previous_data["simulation"]["next_event_id"] = 1
+	var actor_knowledge := (
+		KnownEventStateRecord
+		. create(0, 0, SimulationIds.KNOWLEDGE_ACQUISITION_PERFORMED)
+		. to_dictionary()
+	)
+	var witness_knowledge := (
+		KnownEventStateRecord
+		. create(2, 0, SimulationIds.KNOWLEDGE_ACQUISITION_WITNESSED)
+		. to_dictionary()
+	)
+	var communicated_knowledge := (
+		KnownEventStateRecord
+		. create(
+			1,
+			0,
+			SimulationIds.KNOWLEDGE_ACQUISITION_COMMUNICATED,
+			2,
+			0,
+			SimulationIds.KNOWLEDGE_ACQUISITION_WITNESSED
+		)
+		. to_dictionary()
+	)
+	for old_record in [actor_knowledge, witness_knowledge, communicated_knowledge]:
+		old_record["schema_version"] = 2
+		old_record.erase("acquired_tick")
+		old_record.erase("source_acquisition_method")
+	previous_data["event_knowledge"] = [communicated_knowledge, actor_knowledge, witness_knowledge]
+	previous_data["relationships"] = []
+	var migrated := SimulationStateRecord.from_dictionary(previous_data)
+	_check(migrated != null, "World schema v6 should add deterministic retention metadata")
+	if migrated != null:
+		var records_by_knower := {}
+		for record in migrated.event_knowledge:
+			records_by_knower[record.get_knower_id()] = record
+		var migrated_actor := records_by_knower.get(0) as KnownEventStateRecord
+		var migrated_listener := records_by_knower.get(1) as KnownEventStateRecord
+		_check(
+			migrated_actor != null and migrated_actor.get_acquired_tick() == 0,
+			"Direct v6 knowledge should retain the objective event tick"
+		)
+		_check(
+			(
+				migrated_listener != null
+				and migrated_listener.get_acquired_tick() == 50
+				and (
+					migrated_listener.get_source_acquisition_method()
+					== SimulationIds.KNOWLEDGE_ACQUISITION_WITNESSED
+				)
+			),
+			"Communicated v6 knowledge should receive a fresh lease and source snapshot"
+		)
+	manager.free()
+
+
 func _test_relationship_schema_rejection() -> void:
 	var manager := _create_manager(58)
 	var missing_cause_data: Dictionary = manager.create_state_record().to_dictionary()
@@ -389,7 +470,7 @@ func _test_relationship_schema_rejection() -> void:
 	var event := EconomicEventRecord.create(
 		0,
 		SimulationIds.EVENT_STORAGE_DEPOSITED,
-		1,
+		0,
 		0,
 		SimulationIds.npc_inventory_id(0),
 		SimulationIds.STORAGE_VILLAGE_PANTRY,
@@ -411,7 +492,7 @@ func _test_relationship_schema_rejection() -> void:
 	var unrelated_deposit := EconomicEventRecord.create(
 		0,
 		SimulationIds.EVENT_STORAGE_DEPOSITED,
-		1,
+		0,
 		2,
 		SimulationIds.npc_inventory_id(2),
 		SimulationIds.STORAGE_VILLAGE_PANTRY,
@@ -435,7 +516,7 @@ func _test_relationship_schema_rejection() -> void:
 	var nonpositive_deposit := EconomicEventRecord.create(
 		0,
 		SimulationIds.EVENT_STORAGE_DEPOSITED,
-		1,
+		0,
 		1,
 		SimulationIds.npc_inventory_id(1),
 		SimulationIds.STORAGE_VILLAGE_PANTRY,
@@ -456,26 +537,40 @@ func _test_relationship_schema_rejection() -> void:
 	var provenance_event := EconomicEventRecord.create(
 		0,
 		SimulationIds.EVENT_STORAGE_DEPOSITED,
-		1,
+		0,
 		0,
 		SimulationIds.npc_inventory_id(0),
 		SimulationIds.STORAGE_VILLAGE_PANTRY,
 		SimulationIds.RESOURCE_FOOD,
 		1.0
 	)
-	var missing_source_data: Dictionary = manager.create_state_record().to_dictionary()
-	missing_source_data["economic_events"] = [provenance_event.to_dictionary()]
-	missing_source_data["simulation"]["next_event_id"] = 1
-	missing_source_data["event_knowledge"] = [
+	var historical_source_data: Dictionary = manager.create_state_record().to_dictionary()
+	historical_source_data["economic_events"] = [provenance_event.to_dictionary()]
+	historical_source_data["simulation"]["next_event_id"] = 1
+	historical_source_data["event_knowledge"] = [
 		(
 			KnownEventStateRecord
-			. create(1, 0, SimulationIds.KNOWLEDGE_ACQUISITION_COMMUNICATED, 2)
+			. create(
+				1,
+				0,
+				SimulationIds.KNOWLEDGE_ACQUISITION_COMMUNICATED,
+				2,
+				0,
+				SimulationIds.KNOWLEDGE_ACQUISITION_WITNESSED
+			)
 			. to_dictionary()
 		)
 	]
 	_check(
-		SimulationStateRecord.from_dictionary(missing_source_data) == null,
-		"Communicated knowledge must reference a source who knows the same event"
+		SimulationStateRecord.from_dictionary(historical_source_data) != null,
+		"A listener's provenance should remain valid after the direct source forgets"
+	)
+
+	var unknown_source_data: Dictionary = historical_source_data.duplicate(true)
+	unknown_source_data["event_knowledge"][0]["source_npc_id"] = 999
+	_check(
+		SimulationStateRecord.from_dictionary(unknown_source_data) == null,
+		"Communicated knowledge must reference an existing historical source"
 	)
 
 	var wrong_actor_data: Dictionary = manager.create_state_record().to_dictionary()
@@ -499,12 +594,26 @@ func _test_relationship_schema_rejection() -> void:
 	relayed_source_data["event_knowledge"] = [
 		(
 			KnownEventStateRecord
-			. create(1, 0, SimulationIds.KNOWLEDGE_ACQUISITION_COMMUNICATED, 2)
+			. create(
+				1,
+				0,
+				SimulationIds.KNOWLEDGE_ACQUISITION_COMMUNICATED,
+				2,
+				0,
+				SimulationIds.KNOWLEDGE_ACQUISITION_COMMUNICATED
+			)
 			. to_dictionary()
 		),
 		(
 			KnownEventStateRecord
-			. create(2, 0, SimulationIds.KNOWLEDGE_ACQUISITION_COMMUNICATED, 0)
+			. create(
+				2,
+				0,
+				SimulationIds.KNOWLEDGE_ACQUISITION_COMMUNICATED,
+				0,
+				0,
+				SimulationIds.KNOWLEDGE_ACQUISITION_PERFORMED
+			)
 			. to_dictionary()
 		),
 		(
@@ -517,6 +626,14 @@ func _test_relationship_schema_rejection() -> void:
 		SimulationStateRecord.from_dictionary(relayed_source_data) == null,
 		"Communicated facts must not form a second relay hop in this phase"
 	)
+	var reacquired_source_data: Dictionary = relayed_source_data.duplicate(true)
+	reacquired_source_data["event_knowledge"][0]["source_acquisition_method"] = String(
+		SimulationIds.KNOWLEDGE_ACQUISITION_WITNESSED
+	)
+	_check(
+		SimulationStateRecord.from_dictionary(reacquired_source_data) != null,
+		"Historical direct provenance should survive a source reacquiring the fact differently"
+	)
 
 	var order_independent_data: Dictionary = manager.create_state_record().to_dictionary()
 	order_independent_data["economic_events"] = [provenance_event.to_dictionary()]
@@ -524,7 +641,14 @@ func _test_relationship_schema_rejection() -> void:
 	order_independent_data["event_knowledge"] = [
 		(
 			KnownEventStateRecord
-			. create(1, 0, SimulationIds.KNOWLEDGE_ACQUISITION_COMMUNICATED, 2)
+			. create(
+				1,
+				0,
+				SimulationIds.KNOWLEDGE_ACQUISITION_COMMUNICATED,
+				2,
+				0,
+				SimulationIds.KNOWLEDGE_ACQUISITION_WITNESSED
+			)
 			. to_dictionary()
 		),
 		(
@@ -542,6 +666,22 @@ func _test_relationship_schema_rejection() -> void:
 		SimulationStateRecord.from_dictionary(order_independent_data) != null,
 		"Provenance validation should not depend on knowledge array ordering"
 	)
+
+	var invalid_direct_time_data: Dictionary = manager.create_state_record().to_dictionary()
+	invalid_direct_time_data["simulation"]["tick_count"] = 2
+	invalid_direct_time_data["economic_events"] = [provenance_event.to_dictionary()]
+	invalid_direct_time_data["simulation"]["next_event_id"] = 1
+	invalid_direct_time_data["event_knowledge"] = [
+		(
+			KnownEventStateRecord
+			. create(1, 0, SimulationIds.KNOWLEDGE_ACQUISITION_WITNESSED, -1, 1)
+			. to_dictionary()
+		)
+	]
+	_check(
+		SimulationStateRecord.from_dictionary(invalid_direct_time_data) == null,
+		"Direct witness acquisition must use the immutable objective event tick"
+	)
 	manager.free()