try to fix some binding errors

src/bind_eressea.c

@@ -51,16 +51,18 @@ int eressea_read_orders(const char * filename) {
 }
 
 int eressea_export_json(const char * filename, int flags) {
-    FILE *F = fopen(filename, "w");
-    if (F) {
-        stream out = { 0 };
-        int err;
-        fstream_init(&out, F);
-        err = json_export(&out, flags);
-        fstream_done(&out);
-        return err;
+    if (filename) {
+        FILE *F = fopen(filename, "w");
+        if (F) {
+            stream out = { 0 };
+            int err;
+            fstream_init(&out, F);
+            err = json_export(&out, flags);
+            fstream_done(&out);
+            return err;
+        }
+        perror(filename);
     }
-    perror(filename);
     return -1;
 }
 

src/bind_ship.c

@@ -125,6 +125,16 @@ static int tolua_ship_set_display(lua_State * L)
 
 static int tolua_ship_get_units(lua_State * L)
 {
+#ifndef TOLUA_RELEASE
+tolua_Error tolua_err;
+if (
+!tolua_isusertype(L,1,"ship",0,&tolua_err) || 
+!tolua_isuserdata(L,2,0,&tolua_err) || 
+!tolua_isnoobj(L,3,&tolua_err)
+) goto tolua_lerror;
+else
+#endif
+ {
     ship *sh = (ship *)tolua_tousertype(L, 1, NULL);
     unit **unit_ptr = (unit **)lua_newuserdata(L, sizeof(unit *));
     unit *u = sh->region->units;
@@ -138,6 +148,12 @@ static int tolua_ship_get_units(lua_State * L)
 
     lua_pushcclosure(L, tolua_unitlist_nexts, 1);
     return 1;
+ }
+#ifndef TOLUA_RELEASE
+ tolua_lerror:
+ tolua_error(L, "#ferror in function 'export'.", &tolua_err);
+ return 0;
+#endif
 }
 
 static int tolua_ship_create(lua_State * L)

src/bind_unit.c

@@ -760,17 +760,20 @@ static int tolua_unit_clear_attribs(lua_State *L) {
 }
 
 static int tolua_unit_has_attrib(lua_State *L) {
-    unit *u = (unit *)tolua_tousertype(L, 1, 0);
-    const char *name = tolua_tostring(L, 2, 0);
-    attrib * a = u->attribs;
-    while (a) {
-        if (strcmp(a->type->name, name) == 0) {
-            break;
+    unit *u = (unit *)tolua_tousertype(L, 1, NULL);
+    const char *name = tolua_tostring(L, 2, NULL);
+    if (u && name) {
+        attrib * a = u->attribs;
+        while (a) {
+            if (strcmp(a->type->name, name) == 0) {
+                break;
+            }
+            a = a->nexttype;
         }
-        a = a->nexttype;
+        lua_pushboolean(L, a != NULL);
+        return 1;
     }
-    lua_pushboolean(L, a != NULL);
-    return 1;
+    return 0;
 }
 
 static int tolua_unit_get_key(lua_State * L)

src/bindings.c

@@ -293,17 +293,19 @@ static int tolua_create_curse(lua_State * L)
             ap = &target->attribs;
     }
     if (ap) {
-        const char *cname = tolua_tostring(L, 3, 0);
-        const curse_type *ctype = ct_find(cname);
-        if (ctype) {
-            float vigour = (float)tolua_tonumber(L, 4, 0);
-            int duration = (int)tolua_tonumber(L, 5, 0);
-            float effect = (float)tolua_tonumber(L, 6, 0);
-            int men = (int)tolua_tonumber(L, 7, 0);   /* optional */
-            curse *c = create_curse(u, ap, ctype, vigour, duration, effect, men);
-            if (c) {
-                tolua_pushboolean(L, true);
-                return 1;
+        const char *cname = tolua_tostring(L, 3, NULL);
+        if (cname) {
+            const curse_type *ctype = ct_find(cname);
+            if (ctype) {
+                float vigour = (float)tolua_tonumber(L, 4, 0);
+                int duration = (int)tolua_tonumber(L, 5, 0);
+                float effect = (float)tolua_tonumber(L, 6, 0);
+                int men = (int)tolua_tonumber(L, 7, 0);   /* optional */
+                curse *c = create_curse(u, ap, ctype, vigour, duration, effect, men);
+                if (c) {
+                    tolua_pushboolean(L, true);
+                    return 1;
+                }
             }
         }
     }