add checks for Locked_sexp_*

code/mission/missionparse.cpp

@@ -1065,6 +1065,8 @@ void parse_player_info2(mission *pm)
 
 void parse_cutscenes(mission *pm) 
 {
+	Assertion(Locked_sexp_true >= 0 && Locked_sexp_false >= 0, "SEXPs are not yet initialized!");
+
 	if (optional_string("#Cutscenes"))
 	{
 		mission_cutscene scene;
@@ -1367,6 +1369,8 @@ void parse_music(mission *pm, int flags)
  */
 void parse_fiction(mission * /*pm*/)
 {
+	Assertion(Locked_sexp_true >= 0 && Locked_sexp_false >= 0, "SEXPs are not yet initialized!");
+
 	if (optional_string("#Fiction Viewer"))
 	{
 		bool fiction_viewer_loaded = false;
@@ -1468,6 +1472,8 @@ void parse_cmd_briefs(mission *pm)
  */
 void parse_briefing(mission * /*pm*/, int flags)
 {
+	Assertion(Locked_sexp_true >= 0 && Locked_sexp_false >= 0, "SEXPs are not yet initialized!");
+
 	int nt, i, j, stage_num = 0, icon_num = 0;
 	brief_stage *bs;
 	brief_icon *bi;
@@ -3012,6 +3018,8 @@ extern int parse_warp_params(const WarpParams *inherit_from, WarpDirection direc
  */
 int parse_object(mission *pm, int  /*flag*/, p_object *p_objp)
 {
+	Assertion(Locked_sexp_true >= 0 && Locked_sexp_false >= 0, "SEXPs are not yet initialized!");
+
 	int	i;
     char name[NAME_LENGTH];
 	ship_info *sip;
@@ -7075,13 +7083,18 @@ bool sexp_is_locked_false(int node)
 {
 	// dunno why these are different, but they are
 	if (Fred_running)
+	{
+		Assertion(Locked_sexp_true >= 0 && Locked_sexp_false >= 0, "SEXPs are not yet initialized!");
 		return (node == Locked_sexp_false);
+	}
 	else
 		return (Sexp_nodes[node].value == SEXP_KNOWN_FALSE);
 }
 
 void set_cue_to_false(int *cue)
 {
+	Assertion(Locked_sexp_true >= 0 && Locked_sexp_false >= 0, "SEXPs are not yet initialized!");
+
 	free_sexp2(*cue);
 	*cue = Locked_sexp_false;
 }
@@ -8563,6 +8576,8 @@ int get_warp_in_pos(vec3d *pos, object *objp, float x, float y, float z)
  */
 void mission_bring_in_support_ship( object *requester_objp )
 {
+	Assertion(Locked_sexp_true >= 0 && Locked_sexp_false >= 0, "SEXPs are not yet initialized!");
+
 	vec3d center, warp_in_pos;
 	p_object *pobj;
 	ship *requester_shipp;

code/parse/sexp.cpp

@@ -1424,10 +1424,15 @@ int alloc_sexp(const char *text, int type, int subtype, int first, int rest)
 	int sexp_const = get_operator_const(text);
 
 	if ((sexp_const == OP_TRUE) && (type == SEXP_ATOM) && (subtype == SEXP_ATOM_OPERATOR))
+	{
+		Assertion(Locked_sexp_true >= 0 && Locked_sexp_false >= 0, "SEXPs are not yet initialized!");
 		return Locked_sexp_true;
-
+	}
 	else if ((sexp_const == OP_FALSE) && (type == SEXP_ATOM) && (subtype == SEXP_ATOM_OPERATOR))
+	{
+		Assertion(Locked_sexp_true >= 0 && Locked_sexp_false >= 0, "SEXPs are not yet initialized!");
 		return Locked_sexp_false;
+	}
 
 	node = find_free_sexp();
 
@@ -1526,6 +1531,8 @@ void sexp_mark_persistent(int n)
 		return;
 	}
 
+	Assertion(Locked_sexp_true >= 0 && Locked_sexp_false >= 0, "SEXPs are not yet initialized!");
+
 	// total hack because of the true/false locked sexps -- we should make those persistent as well
 	if ( (n == Locked_sexp_true) || (n == Locked_sexp_false) ){
 		return;
@@ -1548,6 +1555,8 @@ void sexp_unmark_persistent(int n)
 		return;
 	}
 
+	Assertion(Locked_sexp_true >= 0 && Locked_sexp_false >= 0, "SEXPs are not yet initialized!");
+
 	// see sexp_mark_persistent
 	if ( (n == Locked_sexp_true) || (n == Locked_sexp_false) ){
 		return;
@@ -1570,6 +1579,8 @@ int free_one_sexp(int num)
 	Assert(Sexp_nodes[num].type != SEXP_NOT_USED);  // make sure it is actually used
 	Assert(!(Sexp_nodes[num].type & SEXP_FLAG_PERSISTENT));
 
+	Assertion(Locked_sexp_true >= 0 && Locked_sexp_false >= 0, "SEXPs are not yet initialized!");
+
 	// never free these nodes
 	if ((num == Locked_sexp_true) || (num == Locked_sexp_false))
 		return 0;
@@ -1594,6 +1605,8 @@ int free_sexp(int num, int calling_node)
 	Assert(Sexp_nodes[num].type != SEXP_NOT_USED);  // make sure it is actually used
 	Assert(!(Sexp_nodes[num].type & SEXP_FLAG_PERSISTENT));
 
+	Assertion(Locked_sexp_true >= 0 && Locked_sexp_false >= 0, "SEXPs are not yet initialized!");
+
 	// never free these nodes
 	if ((num == -1) || (num == Locked_sexp_true) || (num == Locked_sexp_false))
 		return 0;
@@ -4725,6 +4738,7 @@ int get_sexp()
 		} else {
 			const char *message = nullptr;
 			Assert(last != -1);
+			Assertion(Locked_sexp_true >= 0 && Locked_sexp_false >= 0, "SEXPs are not yet initialized!");
 
 			// Locked_sexp_true and Locked_sexp_false are only meant to represent operator
 			// nodes with no arguments, i.e. (true) and (false). If they appear as "bare"
@@ -10953,6 +10967,8 @@ int eval_perform_actions(int n, int op_num)
 	bool retval_first;
 	Assert( n >= 0 );
 
+	Assertion(Locked_sexp_true >= 0 && Locked_sexp_false >= 0, "SEXPs are not yet initialized!");
+
 	if (op_num == OP_PERFORM_ACTIONS_BOOL_FIRST)
 	{
 		return_cond = CAR(n);
@@ -12198,6 +12214,8 @@ int sexp_num_valid_arguments( int n )
 	if (arg_handler < 0)
 		return 0;
 
+	Assertion(Locked_sexp_true >= 0 && Locked_sexp_false >= 0, "SEXPs are not yet initialized!");
+
 	// the for-* sexps require special handling: they don't list their arguments explicitly but rather generate them on-the-fly
 	auto op_const = get_operator_const(arg_handler);
 	switch (op_const)

code/ship/ship.cpp

@@ -7355,6 +7355,8 @@ static void ship_set(int ship_index, int objnum, int ship_type)
 	ship_weapon	*swp = &shipp->weapons;
 	polymodel *pm = model_get(sip->model_num);
 
+	Assertion(Locked_sexp_true >= 0 && Locked_sexp_false >= 0, "SEXPs are not yet initialized!");
+
 	Assert(strlen(shipp->ship_name) <= NAME_LENGTH - 1);
 	shipp->ship_info_index = ship_type;
 	shipp->objnum = objnum;

fred2/FictionViewerDlg.cpp

@@ -82,6 +82,8 @@ BOOL FictionViewerDlg::OnInitDialog()
 
 void FictionViewerDlg::OnOK() 
 {
+	Assertion(Locked_sexp_true >= 0 && Locked_sexp_false >= 0, "SEXPs are not yet initialized!");
+
 	UpdateData(TRUE);
 
 	// remove whitespace

fred2/briefingeditordlg.cpp

@@ -927,6 +927,8 @@ void briefing_editor_dlg::OnInsertStage()
 
 void briefing_editor_dlg::copy_stage(int from, int to)
 {
+	Assertion(Locked_sexp_true >= 0 && Locked_sexp_false >= 0, "SEXPs are not yet initialized!");
+
 	if ((from < 0) || (from >= Briefing->num_stages)) {
 		Briefing->stages[to].text = "<Text here>";
 		strcpy_s(Briefing->stages[to].voice, "none.wav");

fred2/campaigntreeview.cpp

@@ -749,6 +749,8 @@ void campaign_tree_view::OnLButtonUp(UINT nFlags, CPoint point)
 
 int campaign_tree_view::add_link(int from, int to)
 {
+	Assertion(Locked_sexp_true >= 0 && Locked_sexp_false >= 0, "SEXPs are not yet initialized!");
+
 	if (Total_links >= MAX_CAMPAIGN_TREE_LINKS)
 		return -1;
 
@@ -892,6 +894,8 @@ DROPEFFECT campaign_tree_view::OnDragOver(COleDataObject* pDataObject, DWORD dwK
 
 BOOL campaign_tree_view::OnDrop(COleDataObject* pDataObject, DROPEFFECT dropEffect, CPoint point) 
 {
+	Assertion(Locked_sexp_true >= 0 && Locked_sexp_false >= 0, "SEXPs are not yet initialized!");
+
 	int i, level, pos;
 	cmission *cm;
 	HGLOBAL hGlobal;
@@ -999,6 +1003,8 @@ BOOL campaign_tree_view::OnDrop(COleDataObject* pDataObject, DROPEFFECT dropEffe
 
 void campaign_tree_view::drop_mission(int m, CPoint point)
 {
+	Assertion(Locked_sexp_true >= 0 && Locked_sexp_false >= 0, "SEXPs are not yet initialized!");
+
 	char name[MAX_FILENAME_LEN + 1];
 	int i, item, level, pos;
 	cmission *cm;

fred2/campaigntreewnd.cpp

@@ -305,6 +305,8 @@ void campaign_tree_wnd::OnErrorChecker()
 
 int campaign_tree_wnd::error_checker()
 {
+	Assertion(Locked_sexp_true >= 0 && Locked_sexp_false >= 0, "SEXPs are not yet initialized!");
+
 	int i, j, z;
 	int mcount[MAX_CAMPAIGN_MISSIONS], true_at[MAX_CAMPAIGN_MISSIONS];
 

fred2/freddoc.cpp

@@ -213,6 +213,8 @@ void CFREDDoc::editor_init_mission() {
 }
 
 bool CFREDDoc::load_mission(const char *pathname, int flags) {
+	Assertion(Locked_sexp_true >= 0 && Locked_sexp_false >= 0, "SEXPs are not yet initialized!");
+
 	// make sure we're in the correct working directory!!!!!!
 	chdir(Fred_base_dir);
 

fred2/fredview.cpp

@@ -3083,6 +3083,8 @@ int CFREDView::global_error_check_mixed_player_wing(int w)
 
 int CFREDView::global_error_check_player_wings(int multi)
 {
+	Assertion(Locked_sexp_true >= 0 && Locked_sexp_false >= 0, "SEXPs are not yet initialized!");
+
 	int i, z, err;
 	int starting_wing_count[MAX_STARTING_WINGS];
 	int tvt_wing_count[MAX_TVT_WINGS];

fred2/initialstatus.cpp

@@ -956,6 +956,8 @@ void initial_status::dock(object *objp, int dockpoint, object *other_objp, int o
 
 void initial_status::undock(object *objp1, object *objp2)
 {
+	Assertion(Locked_sexp_true >= 0 && Locked_sexp_false >= 0, "SEXPs are not yet initialized!");
+
 	vec3d v;
 	int ship_num, other_ship_num;
 
@@ -1004,6 +1006,8 @@ void initial_status::undock(object *objp1, object *objp2)
 
 bool set_cue_to_false(int *cue)
 {
+	Assertion(Locked_sexp_true >= 0 && Locked_sexp_false >= 0, "SEXPs are not yet initialized!");
+
 	// if the cue is not false, make it false.  Be sure to set all ship editor dialog functions
 	// to update data before and after we modify the cue.
 	if (*cue != Locked_sexp_false)
@@ -1057,6 +1061,8 @@ void reset_arrival_to_false(int shipnum, bool reset_wing)
 // group with a non-false arrival cue
 void initial_status_mark_dock_leader_helper(object *objp, dock_function_info *infop)
 {
+	Assertion(Locked_sexp_true >= 0 && Locked_sexp_false >= 0, "SEXPs are not yet initialized!");
+
 	ship *shipp = &Ships[objp->instance];
 	int cue_to_check;
 

fred2/management.cpp

@@ -725,6 +725,8 @@ int create_object(vec3d *pos, int waypoint_instance)
 
 int create_player(vec3d *pos, matrix *orient, int type)
 {
+	Assertion(Locked_sexp_true >= 0 && Locked_sexp_false >= 0, "SEXPs are not yet initialized!");
+
 	int obj;
 
 	if (type == -1){

fred2/missionsave.cpp

@@ -2357,6 +2357,8 @@ int CFred_mission_save::save_events()
 
 int CFred_mission_save::save_fiction()
 {
+	Assertion(Locked_sexp_true >= 0 && Locked_sexp_false >= 0, "SEXPs are not yet initialized!");
+
 	if (mission_has_fiction()) {
 		if (Mission_save_format != FSO_FORMAT_RETAIL) {
 			if (optional_string_fred("#Fiction Viewer"))

fred2/reinforcementeditordlg.cpp

@@ -180,6 +180,8 @@ int reinforcement_editor_dlg::query_modified()
 
 void reinforcement_editor_dlg::OnOK()
 {
+	Assertion(Locked_sexp_true >= 0 && Locked_sexp_false >= 0, "SEXPs are not yet initialized!");
+
 	int i, j;
 
 	save_data();

fred2/wing.cpp

@@ -83,6 +83,8 @@ int check_wing_dependencies(int wing_num) {
 }
 
 int create_wing() {
+	Assertion(Locked_sexp_true >= 0 && Locked_sexp_false >= 0, "SEXPs are not yet initialized!");
+
 	char msg[1024];
 	int i, ship, wing = -1, waypoints = 0, count = 0, illegal_ships = 0;
 	int leader, leader_team;

fred2/wing_editor.cpp

@@ -273,6 +273,8 @@ void wing_editor::OnClose()
 // initialize everything that update_data_safe() saves.
 void wing_editor::initialize_data_safe(int full_update)
 {
+	Assertion(Locked_sexp_true >= 0 && Locked_sexp_false >= 0, "SEXPs are not yet initialized!");
+
 	int i, enable = TRUE, player_wing = 0, player_enabled = 1;
 	CComboBox *arrival_box, *departure_box;
 
@@ -574,6 +576,8 @@ void wing_editor::initialize_data(int full_update)
 // Once the error no longer occurs, bypass mode is cleared and data is updated.
 int wing_editor::update_data(int redraw)
 {
+	Assertion(Locked_sexp_true >= 0 && Locked_sexp_false >= 0, "SEXPs are not yet initialized!");
+
 	char *str, old_name[255], buf[512];
 	int i, z;
 	object *ptr;