add check of whether level is loaded before processing command

docs/CHANGELOG.md

@@ -43,6 +43,7 @@ Version 1.9.0 (not released yet)
 - Do not load unnecessary VPPs in dedicated server mode
 - Add level filename to "Level Initializing" console message
 - Properly handle WM_PAINT in dedicated server, may improve performance (DF bug)
+- Fix crash when `verify_level` command is run without a level being loaded
 
 Version 1.8.0 (released 2022-09-17)
 -----------------------------------

game_patch/os/commands.cpp

@@ -9,6 +9,7 @@
 #include <common/utils/list-utils.h>
 #include <algorithm>
 #include <patch_common/CallHook.h>
+#include <patch_common/FunHook.h>
 #include <patch_common/AsmWriter.h>
 
 ConsoleCommand2 dot_cmd{
@@ -91,6 +92,18 @@ DcCommandAlias map_info_cmd{
     level_info_cmd,
 };
 
+// only allow verify_level if a level is loaded (avoid a crash if command is run in menu)
+FunHook<void()> verify_level_cmd_hook{
+    0x0045E1F0,
+    []() {
+        if (rf::level.flags & rf::LEVEL_LOADED) {
+            verify_level_cmd_hook.call_target();
+        } else {
+            rf::console::print("No level loaded!");
+        }
+    }
+};
+
 static void register_builtin_command(const char* name, const char* description, uintptr_t addr)
 {
     static std::vector<std::unique_ptr<rf::console::Command>> builtin_commands;
@@ -192,4 +205,5 @@ void console_commands_init()
     map_cmd.register_cmd();
     level_info_cmd.register_cmd();
     map_info_cmd.register_cmd();
+    verify_level_cmd_hook.install();
 }