(svn r15330) -Fix [FS#2597]: leaking of Squirrel when using circular references (by enabling the GC).

src/ai/ai_core.cpp

@@ -3,6 +3,7 @@
 /** @file ai_core.cpp Implementation of AI. */
 
 #include "../stdafx.h"
+#include "../core/bitmath_func.hpp"
 #include "../company_base.h"
 #include "../company_func.h"
 #include "../debug.h"
@@ -68,6 +69,13 @@
 		}
 	}
 
+	/* Occasionally collect garbage; every 255 ticks do one company.
+	 * Effectively collecting garbage once every two months per AI. */
+	if ((AI::frame_counter & 255) == 0) {
+		CompanyID cid = (CompanyID)GB(AI::frame_counter, 8, 4);
+		if (IsValidCompanyID(cid) && !IsHumanCompany(cid)) GetCompany(cid)->ai_instance->CollectGarbage();
+	}
+
 	_current_company = OWNER_NONE;
 }