From 0d7fc06eb9e87d8e2e916c59e8996cd27af664eb Mon Sep 17 00:00:00 2001
From: Pasi Kallinen <paxed@alt.org>
Date: Sat, 3 Feb 2024 12:55:07 +0200
Subject: [PATCH] Do garbage collection on luacore

Another lua state that is not freed until end of game,
so clean up the stack and do GC regularly.
---
 src/allmain.c |  1 +
 src/cmd.c     |  5 ++++-
 src/do.c      |  1 +
 src/mklev.c   |  1 +
 src/nhlua.c   | 11 +++++++++++
 5 files changed, 18 insertions(+), 1 deletion(-)

diff --git a/src/allmain.c b/src/allmain.c
index 8a9f8319d..6c86710e2 100644
--- a/src/allmain.c
+++ b/src/allmain.c
@@ -512,6 +512,7 @@ moveloop_core(void)
         lua_getglobal(gl.luacore, "nh_callback_run");
         lua_pushstring(gl.luacore, nhcb_name[NHCB_END_TURN]);
         nhl_pcall_handle(gl.luacore, 1, 0, "moveloop_core", NHLpa_panic);
+        lua_settop(gl.luacore, 0);
     }
 }
 
diff --git a/src/cmd.c b/src/cmd.c
index 282439fd4..a337922e3 100644
--- a/src/cmd.c
+++ b/src/cmd.c
@@ -487,8 +487,11 @@ can_do_extcmd(const struct ext_func_tab *extcmd)
         lua_pushstring(gl.luacore, nhcb_name[NHCB_CMD_BEFORE]);
         lua_pushstring(gl.luacore, extcmd->ef_txt);
         nhl_pcall_handle(gl.luacore, 2, 1, "can_do_extcmd", NHLpa_panic);
-        if (!lua_toboolean(gl.luacore, -1))
+        if (!lua_toboolean(gl.luacore, -1)) {
+            lua_settop(gl.luacore, 0);
             return FALSE;
+        }
+        lua_settop(gl.luacore, 0);
     }
 
     if (!wizard && (ecflags & WIZMODECMD)) {
diff --git a/src/do.c b/src/do.c
index 3f0c068a4..0bbf96d3a 100644
--- a/src/do.c
+++ b/src/do.c
@@ -1558,6 +1558,7 @@ goto_level(
         lua_getglobal(gl.luacore, "nh_callback_run");
         lua_pushstring(gl.luacore, nhcb_name[NHCB_LVL_LEAVE]);
         nhl_pcall_handle(gl.luacore, 1, 0, "goto_level", NHLpa_panic);
+        lua_settop(gl.luacore, 0);
     }
 
     /* tethered movement makes level change while trapped feasible */
diff --git a/src/mklev.c b/src/mklev.c
index 9cf7b40c5..d35d9d97a 100644
--- a/src/mklev.c
+++ b/src/mklev.c
@@ -1243,6 +1243,7 @@ makelevel(void)
         lua_getglobal(gl.luacore, "nh_callback_run");
         lua_pushstring(gl.luacore, nhcb_name[NHCB_LVL_ENTER]);
         nhl_pcall_handle(gl.luacore, 1, 0, "makelevel", NHLpa_panic);
+        lua_settop(gl.luacore, 0);
     }
 }
 
diff --git a/src/nhlua.c b/src/nhlua.c
index 95db470d8..012e1e8d1 100644
--- a/src/nhlua.c
+++ b/src/nhlua.c
@@ -174,6 +174,7 @@ l_nhcore_call(int callidx)
           nhcore_call_names[callidx]);*/
         nhcore_call_available[callidx] = FALSE;
     }
+    lua_settop(gl.luacore, 0);
 }
 
 DISABLE_WARNING_UNREACHABLE_CODE
@@ -1115,6 +1116,7 @@ nhl_variable(lua_State *L)
     lua_getglobal(gl.luacore, "nh_lua_variables");
     if (!lua_istable(gl.luacore, -1)) {
         impossible("nh_lua_variables is not a lua table");
+        lua_settop(gl.luacore, 0);
         return 0;
     }
 
@@ -1139,6 +1141,7 @@ nhl_variable(lua_State *L)
             nhl_pcall_handle(L, 0, 1, "nhl_variable-1", NHLpa_panic);
         } else
             nhl_error(L, "Cannot get variable of that type");
+        lua_settop(gl.luacore, 0);
         return 1;
     } else if (argc == 2) {
         /* set nh_lua_variables[key] = value;
@@ -1168,6 +1171,7 @@ nhl_variable(lua_State *L)
             nhl_pcall_handle(gl.luacore, 0, 0, "nhl_variable-3", NHLpa_panic);
         } else
             nhl_error(L, "Cannot set variable of that type");
+        lua_settop(gl.luacore, 0);
         return 0;
     } else
         nhl_error(L, "Wrong number of arguments");
@@ -1189,6 +1193,7 @@ get_nh_lua_variables(void)
     lua_getglobal(gl.luacore, "nh_lua_variables");
     if (!lua_istable(gl.luacore, -1)) {
         impossible("nh_lua_variables is not a lua table");
+        lua_settop(gl.luacore, 0);
         return key;
     }
 
@@ -1196,10 +1201,12 @@ get_nh_lua_variables(void)
     if (lua_type(gl.luacore, -1) == LUA_TFUNCTION) {
         if (nhl_pcall_handle(gl.luacore, 0, 1, "get_nh_lua_variables",
                              NHLpa_impossible)) {
+            lua_settop(gl.luacore, 0);
             return key;
         }
         key = dupstr(lua_tostring(gl.luacore, -1));
     }
+    lua_settop(gl.luacore, 0);
     return key;
 }
 
@@ -1237,6 +1244,7 @@ restore_luadata(NHFILE *nhfp)
     luaL_loadstring(gl.luacore, lua_data);
     free(lua_data);
     nhl_pcall_handle(gl.luacore, 0, 0, "restore_luadata", NHLpa_panic);
+    lua_settop(gl.luacore, 0);
 }
 
 /* local stairs = stairways(); */
@@ -1552,6 +1560,7 @@ nhl_callback(lua_State *L)
         lua_pushstring(gl.luacore, cb);
         lua_pushstring(gl.luacore, fn);
         nhl_pcall_handle(gl.luacore, 2, 0, "nhl_callback", NHLpa_panic);
+        lua_settop(gl.luacore, 0);
     }
     return 0;
 }
@@ -1951,6 +1960,8 @@ nhl_pcall_handle(lua_State *L, int nargs, int nresults, const char *name,
                        lua_tostring(L, -1));
         }
     }
+    if (L == gl.luacore)
+        lua_gc(L, LUA_GCCOLLECT);
     return rv;
 }