Backends: Metal: Fixed resource leak when using multiple contexts. (#7419)

backends/imgui_impl_metal.mm

@@ -306,17 +306,14 @@ void ImGui_ImplMetal_RenderDrawData(ImDrawData* drawData, id<MTLCommandBuffer> c
         indexBufferOffset += (size_t)draw_list->IdxBuffer.Size * sizeof(ImDrawIdx);
     }
 
+    __block MetalContext* sharedMetalContext = bd->SharedMetalContext;
     [commandBuffer addCompletedHandler:^(id<MTLCommandBuffer>)
     {
         dispatch_async(dispatch_get_main_queue(), ^{
-            ImGui_ImplMetal_Data* bd = ImGui_ImplMetal_GetBackendData();
-            if (bd != nullptr)
+            @synchronized(bd->SharedMetalContext.bufferCache)
             {
-                @synchronized(bd->SharedMetalContext.bufferCache)
-                {
-                    [bd->SharedMetalContext.bufferCache addObject:vertexBuffer];
-                    [bd->SharedMetalContext.bufferCache addObject:indexBuffer];
-                }
+                [sharedMetalContext.bufferCache addObject:vertexBuffer];
+                [sharedMetalContext.bufferCache addObject:indexBuffer];
             }
         });
     }];

docs/CHANGELOG.txt

@@ -64,6 +64,7 @@ Other changes:
 - Misc: Fixed misc/cpp/imgui_stdlib.h/.cpp not supporting IMGUI_DISABLE. (#8294) [@juur]
 - Backends: Allegro5: Avoid calling al_set_mouse_cursor() repeatedly since it appears
   to leak on on X11 (#8256). [@Helodity]
+- Backends: Metal: Fixed resource leak when using multiple contexts. (#7419) [@anszom]
 - Backends: Vulkan: Fixed setting VkSwapchainCreateInfoKHR::preTransform for
   platforms not supporting VK_SURFACE_TRANSFORM_IDENTITY_BIT_KHR. (#8222) [@Zer0xFF]