[Tarantool-patches] [PATCH luajit v2 2/2] Fix last commit.

[Maksim Kokryashkin via Tarantool-patches <tarantool-patches@dev.tarantool.org>]

From: Mike Pall <mike>

Reported by PluMGMK.

(cherry-picked from commit 224129a8e64bfa219d35cd03055bf03952f167f6)

The `_VMEVENTS` table, where the error handler for GC finalizers
is set, was not cleared from the stack after the initialization.
This commit adds stack cleanup.

Maxim Kokryashkin:
* added the description and the test for the problem

Part of tarantool/tarantool#9145
---
 src/lib_aux.c                                 |  2 ++
 ...91-fix-finalizer-error-handler-init.test.c | 30 +++++++++++++++++++
 2 files changed, 32 insertions(+)
 create mode 100644 test/tarantool-c-tests/lj-991-fix-finalizer-error-handler-init.test.c

diff --git a/src/lib_aux.c b/src/lib_aux.c
index d532a12f..ecdc67f9 100644
--- a/src/lib_aux.c
+++ b/src/lib_aux.c
@@ -352,6 +352,7 @@ LUALIB_API lua_State *luaL_newstate(void)
     lua_pushcfunction(L, error_finalizer);
     lua_rawseti(L, -2, VMEVENT_HASH(LJ_VMEVENT_ERRFIN));
     G(L)->vmevmask = VMEVENT_MASK(LJ_VMEVENT_ERRFIN);
+    L->top--;
 #endif
   }
   return L;
@@ -378,6 +379,7 @@ LUALIB_API lua_State *luaL_newstate(void)
     lua_pushcfunction(L, error_finalizer);
     lua_rawseti(L, -2, VMEVENT_HASH(LJ_VMEVENT_ERRFIN));
     G(L)->vmevmask = VMEVENT_MASK(LJ_VMEVENT_ERRFIN);
+    L->top--;
 #endif
   }
   return L;
diff --git a/test/tarantool-c-tests/lj-991-fix-finalizer-error-handler-init.test.c b/test/tarantool-c-tests/lj-991-fix-finalizer-error-handler-init.test.c
new file mode 100644
index 00000000..49befc29
--- /dev/null
+++ b/test/tarantool-c-tests/lj-991-fix-finalizer-error-handler-init.test.c
@@ -0,0 +1,30 @@
+#include "lua.h"
+#include "test.h"
+#include "utils.h"
+
+/*
+ * This test demonstrates an uncleared Lua stack after the
+ * initialization of the error handler for GC finalizers.
+ * See https://github.com/luajit/luajit/issues/991 for
+ * details.
+ */
+
+static int stack_is_clean(void *test_state)
+{
+	lua_State *L = test_state;
+  assert_true(lua_gettop(L) == 0);
+	return TEST_EXIT_SUCCESS;
+}
+
+int main(void)
+{
+	lua_State *L = utils_lua_init();
+
+	const struct test_unit tgroup[] = {
+		test_unit_def(stack_is_clean)
+	};
+
+	const int test_result = test_run_group(tgroup, L);
+	utils_lua_close(L);
+	return test_result;
+}
-- 
2.39.3 (Apple Git-145)