fix(scheme): preserve native missing-image behavior

CMakeLists.txt

@@ -81,13 +81,15 @@ install(DIRECTORY "${VGUI2EXTENSION_GAMEDATA_DIR}/" DESTINATION svencoop/metahoo
 option(VGUI2EXTENSION_BUILD_TESTS "Build existing language and IME regression tests" OFF)
 if(VGUI2EXTENSION_BUILD_TESTS)
     enable_testing()
-    foreach(test language_registry_tests ime_window_message_test combobox_unicode_tests career_player_name_tests teammenu_hook_tests default_server_name_tests career_popup_order_tests career_profile_storage_tests buildmode_layout_tests career_end_menu_tests)
+    foreach(test language_registry_tests ime_window_message_test combobox_unicode_tests career_player_name_tests teammenu_hook_tests default_server_name_tests career_popup_order_tests career_profile_storage_tests buildmode_layout_tests career_end_menu_tests border_abi_tests)
         add_executable(${test} "tests/${test}.cpp")
         target_compile_features(${test} PRIVATE cxx_std_17)
         target_compile_options(${test} PRIVATE /W4 /WX /UNDEBUG)
         add_test(NAME ${test} COMMAND ${test})
     endforeach()
     target_sources(career_profile_storage_tests PRIVATE src/CareerProfileStorage.cpp)
+    target_include_directories(border_abi_tests PRIVATE
+        "${METAHOOK_SOURCE_PATH}/include/Interface" "${METAHOOK_SOURCE_PATH}/include/VGUI")
 endif()
 
 # The aggregate solution owns its single LaunchGame target.

memory/build_and_verification.md

@@ -6,6 +6,16 @@ permalink: vgui2extension/build-and-verification
 
 # Build and verification
 
+## Zombie Panic missing images and border ABI (2026-11-07)
+
+- Trigger: zp 10210 constructs its scoreboard using `GetImage("ui/icons/scoreboard/icon_dono0", false)->SetSize(32, 32)`, although that image is absent from the installed resources.
+- Root cause: native VGUI returns a Bitmap for the missing image, but our scheme manager deleted invalid Bitmaps and returned NULL. The client's unchecked call then dereferenced zero. Restoring the native getter in a diagnostic process bypassed this failure and exposed a separate `IBorder` virtual-slot mismatch.
+- Fix: cache and return invalid Bitmaps, preserving native missing-image behavior; their existing `Paint` implementation safely skips invalid textures. Remove `ParseSideSettings` from the MetaHook public `IBorder` interface so native slot 6/7 dispatch reaches `GetName`/`SetName`; keep parsing as a private nonvirtual `Border` helper.
+- Regression: `border_abi_tests` calls slots 6/7 with the native calling convention, fails on the old header, and passes on the fixed header. Aggregate Debug/Win32 build, all 11 plugin CTests, and pinned formatting checks for both components passed.
+- Runtime verification: deployed the rebuilt aggregate to Zombie Panic Mod and used CDB without runtime patches. The missing image returned a VGUI2Extension Bitmap and the original client `Start()` returned successfully. Both prior crash paths were traversed without access violations or runtime stack-check failures.
+- Limit: halflife-mcp startup then stopped at a different Renderer error: `GameStudioRenderer_StudioDrawModel` is missing from the matched client gamedata snapshot. No successful main-menu/map/visual regression is claimed. Test processes exited.
+- Evidence: aggregate `build/x86/Debug/deployment/zp-fixed-start-verification.log` and the game's `fatalerror-20261107-192620-718-16304.log`. Applies to scheme replacements serving native GoldSrc clients, not only zp.
+
 ## Build structure
 
 The root CMake uses MSVC x86, C++20, Debug/Release, a static CRT.

src/Scheme2.cpp

@@ -1114,12 +1114,8 @@ IImage* CSchemeManager::GetImage(const char* imageName, bool hardwareFiltered)
         return NULL;
     }
 
-    if (imageName[0] && !pBitmap->IsValid())
-    {
-        delete pBitmap;
-        return NULL;
-    }
-
+    // Native VGUI returns a Bitmap even when the texture is missing. Clients may
+    // use it without a null check; invalid Bitmaps already skip painting safely.
     searchBitmap.bitmap = pBitmap;
     m_Bitmaps.Insert(searchBitmap);
     return pBitmap;

tests/border_abi_tests.cpp

@@ -0,0 +1,66 @@
+#include <vgui/IBorder.h>
+
+#include <cassert>
+#include <cstddef>
+#include <cstdio>
+#include <cstdlib>
+
+class BorderProbe : public vgui::IBorder
+{
+public:
+    void Paint(vgui::VPANEL) override {}
+    void Paint(int, int, int, int) override {}
+    void Paint(int, int, int, int, int, int, int) override {}
+    void SetInset(int, int, int, int) override {}
+    void GetInset(int&, int&, int&, int&) override {}
+    void ApplySchemeSettings(vgui::IScheme*, KeyValues*) override {}
+
+    // If this helper becomes virtual again, native GetName dispatch must fail.
+    void ParseSideSettings(int, KeyValues*, vgui::IScheme*)
+    {
+        std::fputs("Native IBorder dispatch reached ParseSideSettings\n", stderr);
+        std::exit(EXIT_FAILURE);
+    }
+
+    const char* GetName() override
+    {
+        ++getNameCalls;
+        return name;
+    }
+
+    void SetName(const char* value) override
+    {
+        ++setNameCalls;
+        name = value;
+    }
+
+    backgroundtype_e GetBackgroundType() override { return BACKGROUND_FILLED; }
+    bool             PaintFirst() override { return false; }
+
+    const char* name         = nullptr;
+    int         getNameCalls = 0;
+    int         setNameCalls = 0;
+};
+
+int main()
+{
+    // GoldSrc clients call these slots using the native IBorder ABI.
+    constexpr std::size_t NativeGetNameSlot = 6;
+    constexpr std::size_t NativeSetNameSlot = 7;
+    using GetNameFn                         = const char*(__fastcall*)(void*, int);
+    using SetNameFn                         = void(__fastcall*)(void*, int, const char*);
+
+    BorderProbe border;
+    auto        vtable  = *reinterpret_cast<void***>(&border);
+    auto        getName = reinterpret_cast<GetNameFn>(vtable[NativeGetNameSlot]);
+    auto        setName = reinterpret_cast<SetNameFn>(vtable[NativeSetNameSlot]);
+
+    assert(nullptr == getName(&border, 0));
+    assert(1 == border.getNameCalls);
+
+    const char name[] = "ScoreboardBorder";
+    setName(&border, 0, name);
+    assert(1 == border.setNameCalls);
+    assert(name == getName(&border, 0));
+    assert(2 == border.getNameCalls);
+}