fix minor bugs in treeSeqMetadata()

VERSIONS

@@ -100,6 +100,7 @@ development head (in the master branch):
 		add recipe 15.22, "Complex multi-chromosome inheritance with addMultiRecombinant()", to illustrate addMultiRecombinant()
 		modified recipes 15.14 and 15.21 to illustrate that NULL can now be passed to addRecombinant() for breaks to get automatic breakpoint generation
 		cleaned up the confusion around Dictionary vs. DictionaryBase; methods/functions can now use Dictionary in their signature without problems
+		fix a bug in treeSeqMetadata(); if no metadata was found, it would return object<Dictionary>(0), not an empty Dictionary object (and it leaked)
 
 
 version 4.3 (Eidos version 3.3):

core/slim_functions.cpp

@@ -1963,8 +1963,12 @@ EidosValue_SP SLiM_ExecuteFunction_treeSeqMetadata(const std::vector<EidosValue_
 	{
 		tsk_table_collection_free(&temp_tables);
 
-		// With no metadata, return an empty dictionary
-		return EidosValue_SP(new (gEidosValuePool->AllocateChunk()) EidosValue_Object(gEidosDictionaryRetained_Class));
+		// With no metadata, return an empty dictionary.  BCH 1/17/2025: prior to SLiM 5, this erroneously returned object<Dictionary>(0)
+		EidosDictionaryRetained *objectElement = new EidosDictionaryRetained();
+		EidosValue_SP result_SP = EidosValue_SP(new (gEidosValuePool->AllocateChunk()) EidosValue_Object(objectElement, gEidosDictionaryRetained_Class));
+
+		objectElement->Release();	// retained by result_SP
+		return result_SP;
 	}
 
 	std::string metadata_schema_string(temp_tables.metadata_schema, temp_tables.metadata_schema_length);
@@ -2015,6 +2019,7 @@ EidosValue_SP SLiM_ExecuteFunction_treeSeqMetadata(const std::vector<EidosValue_
 	EidosDictionaryRetained *objectElement = new EidosDictionaryRetained();
 	EidosValue_SP result_SP = EidosValue_SP(new (gEidosValuePool->AllocateChunk()) EidosValue_Object(objectElement, gEidosDictionaryRetained_Class));
 
+	objectElement->Release();	// retained by result_SP
 	objectElement->AddJSONFrom(metadata);
 	objectElement->ContentsChanged("treeSeqMetadata()");
 	return result_SP;