From 9cf9d2be8366a0b4193cfb31da911184b0db6898 Mon Sep 17 00:00:00 2001
From: ocornut <omar@miracleworld.net>
Date: Wed, 17 Sep 2025 18:06:03 +0200
Subject: [PATCH] Debug Tools: ID Stack Tool: fixed a crash when using
 PushOverrideID(0) during a query. (#8937, #4631)

---
 docs/CHANGELOG.txt |  2 ++
 imgui.cpp          | 11 +++++++++++
 imgui_internal.h   |  1 +
 3 files changed, 14 insertions(+)

diff --git a/docs/CHANGELOG.txt b/docs/CHANGELOG.txt
index b1575131c..48de7e881 100644
--- a/docs/CHANGELOG.txt
+++ b/docs/CHANGELOG.txt
@@ -103,6 +103,8 @@ Other Changes:
   is now skipped. (#8904, #4631)
 - Debug Tools: ID Stack Tool: added option to hex-encode non-ASCII characters in
   output path. (#8904, #4631)
+- Debug Tools: ID Stack Tool: fixed a crash when using PushOverrideID(0) during
+  a query. (#8937, #4631)
 - Debug Tools: Fixed assertion failure when opening a combo box while using
   io.ConfigDebugBeginReturnValueOnce/ConfigDebugBeginReturnValueLoop. (#8931) [@harrymander]
 - Demo: tweaked ShowFontSelector() and ShowStyleSelector() to update selection
diff --git a/imgui.cpp b/imgui.cpp
index 94092c3e4..88ceb1f6c 100644
--- a/imgui.cpp
+++ b/imgui.cpp
@@ -17662,6 +17662,7 @@ void ImGui::UpdateDebugToolStackQueries()
 
     // Clear hook when id stack tool is not visible
     g.DebugHookIdInfoId = 0;
+    tool->QueryHookActive = false;
     if (g.FrameCount != tool->LastActiveFrame + 1)
         return;
 
@@ -17687,11 +17688,15 @@ void ImGui::UpdateDebugToolStackQueries()
     // Update hook
     stack_level = tool->StackLevel;
     if (stack_level == -1)
+    {
         g.DebugHookIdInfoId = query_main_id;
+        tool->QueryHookActive = true;
+    }
     else if (stack_level >= 0 && stack_level < tool->Results.Size)
     {
         g.DebugHookIdInfoId = tool->Results[stack_level].ID;
         tool->Results[stack_level].QueryFrameCount++;
+        tool->QueryHookActive = true;
     }
 }
 
@@ -17701,11 +17706,17 @@ void ImGui::DebugHookIdInfo(ImGuiID id, ImGuiDataType data_type, const void* dat
     ImGuiContext& g = *GImGui;
     ImGuiWindow* window = g.CurrentWindow;
     ImGuiIDStackTool* tool = &g.DebugIDStackTool;
+    if (tool->QueryHookActive == false)
+    {
+        IM_ASSERT(id == 0);
+        return;
+    }
 
     // Step 0: stack query
     // This assumes that the ID was computed with the current ID stack, which tends to be the case for our widget.
     if (tool->StackLevel == -1)
     {
+        IM_ASSERT(tool->Results.Size == 0);
         tool->StackLevel++;
         tool->Results.resize(window->IDStack.Size + 1, ImGuiStackLevelInfo());
         for (int n = 0; n < window->IDStack.Size + 1; n++)
diff --git a/imgui_internal.h b/imgui_internal.h
index 32d04df4e..d2a3f4d8b 100644
--- a/imgui_internal.h
+++ b/imgui_internal.h
@@ -2128,6 +2128,7 @@ struct ImGuiIDStackTool
     int                     StackLevel;                 // -1: query stack and resize Results, >= 0: individual stack level
     ImGuiID                 QueryMainId;                // ID to query details for
     ImVector<ImGuiStackLevelInfo> Results;
+    bool                    QueryHookActive;            // Used to disambiguate the case where DebugHookIdInfoId == 0 which is valid.
     bool                    OptHexEncodeNonAsciiChars;
     bool                    OptCopyToClipboardOnCtrlC;
     float                   CopyToClipboardLastTime;