Backends: Added more implicit asserts to detect invalid/redundant calls to Shutdown functions. (#4562)

backends/imgui_impl_allegro5.cpp

@@ -335,8 +335,9 @@ bool ImGui_ImplAllegro5_Init(ALLEGRO_DISPLAY* display)
 
 void ImGui_ImplAllegro5_Shutdown()
 {
-    ImGuiIO& io = ImGui::GetIO();
     ImGui_ImplAllegro5_Data* bd = ImGui_ImplAllegro5_GetBackendData();
+    IM_ASSERT(bd != NULL && "No platform backend to shutdown, or already shutdown?");
+    ImGuiIO& io = ImGui::GetIO();
 
     ImGui_ImplAllegro5_InvalidateDeviceObjects();
     if (bd->VertexDecl)

backends/imgui_impl_dx10.cpp

@@ -556,8 +556,9 @@ bool    ImGui_ImplDX10_Init(ID3D10Device* device)
 
 void ImGui_ImplDX10_Shutdown()
 {
-    ImGuiIO& io = ImGui::GetIO();
     ImGui_ImplDX10_Data* bd = ImGui_ImplDX10_GetBackendData();
+    IM_ASSERT(bd != NULL && "No renderer backend to shutdown, or already shutdown?");
+    ImGuiIO& io = ImGui::GetIO();
 
     ImGui_ImplDX10_InvalidateDeviceObjects();
     if (bd->pFactory) { bd->pFactory->Release(); }

backends/imgui_impl_dx11.cpp

@@ -571,8 +571,9 @@ bool    ImGui_ImplDX11_Init(ID3D11Device* device, ID3D11DeviceContext* device_co
 
 void ImGui_ImplDX11_Shutdown()
 {
-    ImGuiIO& io = ImGui::GetIO();
     ImGui_ImplDX11_Data* bd = ImGui_ImplDX11_GetBackendData();
+    IM_ASSERT(bd != NULL && "No renderer backend to shutdown, or already shutdown?");
+    ImGuiIO& io = ImGui::GetIO();
 
     ImGui_ImplDX11_InvalidateDeviceObjects();
     if (bd->pFactory)             { bd->pFactory->Release(); }

backends/imgui_impl_dx12.cpp

@@ -725,8 +725,9 @@ bool ImGui_ImplDX12_Init(ID3D12Device* device, int num_frames_in_flight, DXGI_FO
 
 void ImGui_ImplDX12_Shutdown()
 {
-    ImGuiIO& io = ImGui::GetIO();
     ImGui_ImplDX12_Data* bd = ImGui_ImplDX12_GetBackendData();
+    IM_ASSERT(bd != NULL && "No renderer backend to shutdown, or already shutdown?");
+    ImGuiIO& io = ImGui::GetIO();
 
     ImGui_ImplDX12_InvalidateDeviceObjects();
     delete[] bd->pFrameResources;

backends/imgui_impl_dx9.cpp

@@ -295,8 +295,9 @@ bool ImGui_ImplDX9_Init(IDirect3DDevice9* device)
 
 void ImGui_ImplDX9_Shutdown()
 {
-    ImGuiIO& io = ImGui::GetIO();
     ImGui_ImplDX9_Data* bd = ImGui_ImplDX9_GetBackendData();
+    IM_ASSERT(bd != NULL && "No renderer backend to shutdown, or already shutdown?");
+    ImGuiIO& io = ImGui::GetIO();
 
     ImGui_ImplDX9_InvalidateDeviceObjects();
     if (bd->pd3dDevice) { bd->pd3dDevice->Release(); }

backends/imgui_impl_glfw.cpp

@@ -308,8 +308,9 @@ bool ImGui_ImplGlfw_InitForOther(GLFWwindow* window, bool install_callbacks)
 
 void ImGui_ImplGlfw_Shutdown()
 {
-    ImGuiIO& io = ImGui::GetIO();
     ImGui_ImplGlfw_Data* bd = ImGui_ImplGlfw_GetBackendData();
+    IM_ASSERT(bd != NULL && "No platform backend to shutdown, or already shutdown?");
+    ImGuiIO& io = ImGui::GetIO();
 
     if (bd->InstalledCallbacks)
     {

backends/imgui_impl_opengl2.cpp

@@ -86,8 +86,9 @@ bool    ImGui_ImplOpenGL2_Init()
 
 void    ImGui_ImplOpenGL2_Shutdown()
 {
-    ImGuiIO& io = ImGui::GetIO();
     ImGui_ImplOpenGL2_Data* bd = ImGui_ImplOpenGL2_GetBackendData();
+    IM_ASSERT(bd != NULL && "No renderer backend to shutdown, or already shutdown?");
+    ImGuiIO& io = ImGui::GetIO();
 
     ImGui_ImplOpenGL2_DestroyDeviceObjects();
     io.BackendRendererName = NULL;

backends/imgui_impl_opengl3.cpp

@@ -269,8 +269,9 @@ bool    ImGui_ImplOpenGL3_Init(const char* glsl_version)
 
 void    ImGui_ImplOpenGL3_Shutdown()
 {
-    ImGuiIO& io = ImGui::GetIO();
     ImGui_ImplOpenGL3_Data* bd = ImGui_ImplOpenGL3_GetBackendData();
+    IM_ASSERT(bd != NULL && "No renderer backend to shutdown, or already shutdown?");
+    ImGuiIO& io = ImGui::GetIO();
 
     ImGui_ImplOpenGL3_DestroyDeviceObjects();
     io.BackendRendererName = NULL;

backends/imgui_impl_sdl.cpp

@@ -280,8 +280,9 @@ bool ImGui_ImplSDL2_InitForMetal(SDL_Window* window)
 
 void ImGui_ImplSDL2_Shutdown()
 {
-    ImGuiIO& io = ImGui::GetIO();
     ImGui_ImplSDL2_Data* bd = ImGui_ImplSDL2_GetBackendData();
+    IM_ASSERT(bd != NULL && "No platform backend to shutdown, or already shutdown?");
+    ImGuiIO& io = ImGui::GetIO();
 
     if (bd->ClipboardTextData)
         SDL_free(bd->ClipboardTextData);

backends/imgui_impl_vulkan.cpp

@@ -1048,8 +1048,9 @@ bool    ImGui_ImplVulkan_Init(ImGui_ImplVulkan_InitInfo* info, VkRenderPass rend
 
 void ImGui_ImplVulkan_Shutdown()
 {
-    ImGuiIO& io = ImGui::GetIO();
     ImGui_ImplVulkan_Data* bd = ImGui_ImplVulkan_GetBackendData();
+    IM_ASSERT(bd != NULL && "No renderer backend to shutdown, or already shutdown?");
+    ImGuiIO& io = ImGui::GetIO();
 
     ImGui_ImplVulkan_DestroyDeviceObjects();
     io.BackendRendererName = NULL;

backends/imgui_impl_win32.cpp

@@ -172,8 +172,9 @@ bool    ImGui_ImplWin32_Init(void* hwnd)
 
 void    ImGui_ImplWin32_Shutdown()
 {
-    ImGuiIO& io = ImGui::GetIO();
     ImGui_ImplWin32_Data* bd = ImGui_ImplWin32_GetBackendData();
+    IM_ASSERT(bd != NULL && "No platform backend to shutdown, or already shutdown?");
+    ImGuiIO& io = ImGui::GetIO();
 
     // Unload XInput library
 #ifndef IMGUI_IMPL_WIN32_DISABLE_GAMEPAD

docs/CHANGELOG.txt

@@ -73,6 +73,7 @@ Other Changes:
 - Fonts: imgui_freetype: Fixed crash when FT_Render_Glyph() fails to render a glyph and returns NULL
   (which apparently happens with Freetype 2.11). (#4394, #4145?).
 - Fonts: Fixed ImFontAtlas::ClearInputData() marking atlas as not built. (#4455, #3487)
+- Backends: Added more implicit asserts to detect invalid/redundant calls to Shutdown functions. (#4562)
 - Backends: OpenGL3: Fixed our custom GL loader conflicting with user using GL3W. (#4445) [@rokups]
 - Backends: WebGPU: Fixed for latest specs. (#4472) [@Kangz]
 - Backends: Metal: Fixed a crash when clipping rect larger than framebuffer is submitted via