Internals: added experimental ErrorCheckEndFrameRecover() to unroll/end/pop. (#1651, #3600)

imgui.cpp

@@ -6842,8 +6842,8 @@ static void ImGui::ErrorCheckNewFrameSanityChecks()
     // (IF YOU GET A WARNING OR COMPILE ERROR HERE: it means you assert macro is incorrectly defined!
     //  If your macro uses multiple statements, it NEEDS to be surrounded by a 'do { ... } while (0)' block.
     //  This is a common C/C++ idiom to allow multiple statements macros to be used in control flow blocks.)
-    // #define IM_ASSERT(EXPR)   SomeCode(EXPR); SomeMoreCode();                    // Wrong!
+    // #define IM_ASSERT(EXPR)   if (SomeCode(EXPR)) SomeMoreCode();                    // Wrong!
-    // #define IM_ASSERT(EXPR)   do { SomeCode(EXPR); SomeMoreCode(); } while (0)   // Correct!
+    // #define IM_ASSERT(EXPR)   do { if (SomeCode(EXPR)) SomeMoreCode(); } while (0)   // Correct!
     if (true) IM_ASSERT(1); else IM_ASSERT(0);
 
     // Check user data
@@ -6852,21 +6852,21 @@ static void ImGui::ErrorCheckNewFrameSanityChecks()
     IM_ASSERT((g.IO.DeltaTime > 0.0f || g.FrameCount == 0)              && "Need a positive DeltaTime!");
     IM_ASSERT((g.FrameCount == 0 || g.FrameCountEnded == g.FrameCount)  && "Forgot to call Render() or EndFrame() at the end of the previous frame?");
     IM_ASSERT(g.IO.DisplaySize.x >= 0.0f && g.IO.DisplaySize.y >= 0.0f  && "Invalid DisplaySize value!");
-    IM_ASSERT(g.IO.Fonts->Fonts.Size > 0                                && "Font Atlas not built. Did you call io.Fonts->GetTexDataAsRGBA32() / GetTexDataAsAlpha8() ?");
+    IM_ASSERT(g.IO.Fonts->Fonts.Size > 0                                && "Font Atlas not built. Did you call io.Fonts->GetTexDataAsRGBA32() / GetTexDataAsAlpha8()?");
-    IM_ASSERT(g.IO.Fonts->Fonts[0]->IsLoaded()                          && "Font Atlas not built. Did you call io.Fonts->GetTexDataAsRGBA32() / GetTexDataAsAlpha8() ?");
+    IM_ASSERT(g.IO.Fonts->Fonts[0]->IsLoaded()                          && "Font Atlas not built. Did you call io.Fonts->GetTexDataAsRGBA32() / GetTexDataAsAlpha8()?");
     IM_ASSERT(g.Style.CurveTessellationTol > 0.0f                       && "Invalid style setting!");
     IM_ASSERT(g.Style.CircleSegmentMaxError > 0.0f                      && "Invalid style setting!");
-    IM_ASSERT(g.Style.Alpha >= 0.0f && g.Style.Alpha <= 1.0f            && "Invalid style setting. Alpha cannot be negative (allows us to avoid a few clamps in color computations)!");
+    IM_ASSERT(g.Style.Alpha >= 0.0f && g.Style.Alpha <= 1.0f            && "Invalid style setting!"); // Allows us to avoid a few clamps in color computations
     IM_ASSERT(g.Style.WindowMinSize.x >= 1.0f && g.Style.WindowMinSize.y >= 1.0f && "Invalid style setting.");
     IM_ASSERT(g.Style.WindowMenuButtonPosition == ImGuiDir_None || g.Style.WindowMenuButtonPosition == ImGuiDir_Left || g.Style.WindowMenuButtonPosition == ImGuiDir_Right);
     for (int n = 0; n < ImGuiKey_COUNT; n++)
         IM_ASSERT(g.IO.KeyMap[n] >= -1 && g.IO.KeyMap[n] < IM_ARRAYSIZE(g.IO.KeysDown) && "io.KeyMap[] contains an out of bound value (need to be 0..512, or -1 for unmapped key)");
 
-    // Perform simple check: required key mapping (we intentionally do NOT check all keys to not pressure user into setting up everything, but Space is required and was only recently added in 1.60 WIP)
+    // Check: required key mapping (we intentionally do NOT check all keys to not pressure user into setting up everything, but Space is required and was only added in 1.60 WIP)
     if (g.IO.ConfigFlags & ImGuiConfigFlags_NavEnableKeyboard)
         IM_ASSERT(g.IO.KeyMap[ImGuiKey_Space] != -1 && "ImGuiKey_Space is not mapped, required for keyboard navigation.");
 
-    // Perform simple check: the beta io.ConfigWindowsResizeFromEdges option requires backend to honor mouse cursor changes and set the ImGuiBackendFlags_HasMouseCursors flag accordingly.
+    // Check: the io.ConfigWindowsResizeFromEdges option requires backend to honor mouse cursor changes and set the ImGuiBackendFlags_HasMouseCursors flag accordingly.
     if (g.IO.ConfigWindowsResizeFromEdges && !(g.IO.BackendFlags & ImGuiBackendFlags_HasMouseCursors))
         g.IO.ConfigWindowsResizeFromEdges = false;
 }
@@ -6885,6 +6885,9 @@ static void ImGui::ErrorCheckEndFrameSanityChecks()
     IM_ASSERT((key_mod_flags == 0 || g.IO.KeyMods == key_mod_flags) && "Mismatching io.KeyCtrl/io.KeyShift/io.KeyAlt/io.KeySuper vs io.KeyMods");
     IM_UNUSED(key_mod_flags);
 
+    // Recover from errors
+    //ErrorCheckEndFrameRecover();
+
     // Report when there is a mismatch of Begin/BeginChild vs End/EndChild calls. Important: Remember that the Begin/BeginChild API requires you
     // to always call End/EndChild even if Begin/BeginChild returns false! (this is unfortunately inconsistent with most other Begin* API).
     if (g.CurrentWindowStack.Size != 1)
@@ -6904,6 +6907,78 @@ static void ImGui::ErrorCheckEndFrameSanityChecks()
     IM_ASSERT_USER_ERROR(g.GroupStack.Size == 0, "Missing EndGroup call!");
 }
 
+// Experimental recovery from incorrect usage of BeginXXX/EndXXX/PushXXX/PopXXX calls.
+// Must be called during or before EndFrame().
+// This is generally flawed as we are not necessarily End/Popping things in the right order.
+// FIXME: Can't recover from inside BeginTabItem/EndTabItem yet.
+// FIXME: Can't recover from interleaved BeginTabBar/Begin
+void    ImGui::ErrorCheckEndFrameRecover(ImGuiErrorLogCallback log_callback, void* user_data)
+{
+    // PVS-Studio V1044 is "Loop break conditions do not depend on the number of iterations"
+    ImGuiContext& g = *GImGui;
+    while (g.CurrentWindowStack.Size > 0)
+    {
+#ifdef IMGUI_HAS_TABLE
+        while (g.CurrentTable && (g.CurrentTable->OuterWindow == g.CurrentWindow || g.CurrentTable->InnerWindow == g.CurrentWindow))
+        {
+            if (log_callback) log_callback(user_data, "Recovered from missing EndTable() in '%s'", g.CurrentTable->OuterWindow->Name);
+            EndTable();
+        }
+#endif
+        ImGuiWindow* window = g.CurrentWindow;
+        while (g.CurrentTabBar != NULL) //-V1044
+        {
+            if (log_callback) log_callback(user_data, "Recovered from missing EndTabBar() in '%s'", window->Name);
+            EndTabBar();
+        }
+        while (g.CurrentWindow->DC.TreeDepth > 0) //-V1044
+        {
+            if (log_callback) log_callback(user_data, "Recovered from missing TreePop() in '%s'", window->Name);
+            TreePop();
+        }
+        while (g.GroupStack.Size > g.CurrentWindow->DC.StackSizesOnBegin.SizeOfGroupStack) //-V1044
+        {
+            if (log_callback) log_callback(user_data, "Recovered from missing EndGroup() in '%s'", window->Name);
+            EndGroup();
+        }
+        while (g.CurrentWindow->IDStack.Size > 1) //-V1044
+        {
+            if (log_callback) log_callback(user_data, "Recovered from missing PopID() in '%s'", window->Name);
+            PopID();
+        }
+        while (g.ColorStack.Size > g.CurrentWindow->DC.StackSizesOnBegin.SizeOfColorStack) //-V1044
+        {
+            if (log_callback) log_callback(user_data, "Recovered from missing PopStyleColor() in '%s' for ImGuiCol_%s", window->Name, GetStyleColorName(g.ColorStack.back().Col));
+            PopStyleColor();
+        }
+        while (g.StyleVarStack.Size > g.CurrentWindow->DC.StackSizesOnBegin.SizeOfStyleVarStack) //-V1044
+        {
+            if (log_callback) log_callback(user_data, "Recovered from missing PopStyleVar() in '%s'", window->Name);
+            PopStyleVar();
+        }
+        while (g.FocusScopeStack.Size > g.CurrentWindow->DC.StackSizesOnBegin.SizeOfFocusScopeStack) //-V1044
+        {
+            if (log_callback) log_callback(user_data, "Recovered from missing PopFocusScope() in '%s'", window->Name);
+            PopFocusScope();
+        }
+        if (g.CurrentWindowStack.Size == 1)
+        {
+            IM_ASSERT(g.CurrentWindow->IsFallbackWindow);
+            break;
+        }
+        if (g.CurrentWindow->Flags & ImGuiWindowFlags_ChildWindow)
+        {
+            if (log_callback) log_callback(user_data, "Recovered from missing EndChild() for '%s'", window->Name);
+            EndChild();
+        }
+        else
+        {
+            if (log_callback) log_callback(user_data, "Recovered from missing End() for '%s'", window->Name);
+            End();
+        }
+    }
+}
+
 // Save current stack sizes for later compare
 void ImGuiStackSizes::SetToCurrentState()
 {

imgui_internal.h

@@ -129,6 +129,8 @@ typedef int ImGuiSeparatorFlags;        // -> enum ImGuiSeparatorFlags_     // F
 typedef int ImGuiTextFlags;             // -> enum ImGuiTextFlags_          // Flags: for TextEx()
 typedef int ImGuiTooltipFlags;          // -> enum ImGuiTooltipFlags_       // Flags: for BeginTooltipEx()
 
+typedef void (*ImGuiErrorLogCallback)(void* user_data, const char* fmt, ...);
+
 //-----------------------------------------------------------------------------
 // [SECTION] Context pointer
 // See implementation of this variable in imgui.cpp for comments and details.
@@ -2082,6 +2084,7 @@ namespace ImGui
     IMGUI_API void          GcAwakeTransientWindowBuffers(ImGuiWindow* window);
 
     // Debug Tools
+    IMGUI_API void          ErrorCheckEndFrameRecover(ImGuiErrorLogCallback log_callback, void* user_data = NULL);
     inline void             DebugDrawItemRect(ImU32 col = IM_COL32(255,0,0,255))    { ImGuiContext& g = *GImGui; ImGuiWindow* window = g.CurrentWindow; GetForegroundDrawList(window)->AddRect(window->DC.LastItemRect.Min, window->DC.LastItemRect.Max, col); }
     inline void             DebugStartItemPicker()                                  { ImGuiContext& g = *GImGui; g.DebugItemPickerActive = true; }