🚧 fixed partial port of native commit cc2177de

Debug Tools: Added io.ConfigDebugBeginReturnValueOnce / io.ConfigDebugBeginReturnValueLoop options.

Author: elect86

core/src/main/kotlin/imgui/api/demoDebugInformations.kt

@@ -281,6 +281,10 @@ interface demoDebugInformations {
                     }
                     unindent()
                 }
+
+            checkbox("Debug Begin/BeginChild return value", io::configDebugBeginReturnValueLoop)
+            sameLine()
+            metricsHelpMarker("Some calls to Begin()/BeginChild() will return false.\n\nWill cycle through window depths then repeat. Windows should be flickering while running.")
         }
 
         // Windows

core/src/main/kotlin/imgui/api/windows.kt

@@ -736,6 +736,14 @@ interface windows {
             }
         }
 
+        // [DEBUG] io.ConfigDebugBeginReturnValue override return value to test Begin/End and BeginChild/EndChild behaviors.
+        // (The implicit fallback window is NOT automatically ended allowing it to always be able to receive commands without crashing)
+        if (!window.isFallbackWindow && (g.io.configDebugBeginReturnValueOnce && windowJustCreated || g.io.configDebugBeginReturnValueLoop && g.debugBeginReturnValueCullDepth == g.currentWindowStack.size)) {
+            if (window.autoFitFrames.x > 0) window.autoFitFrames.x++
+            if (window.autoFitFrames.y > 0) window.autoFitFrames.y++
+            return false
+        }
+
         return !window.skipItems
     }
 

core/src/main/kotlin/imgui/statics/errorCheckingAndDebugTools.kt

@@ -67,7 +67,9 @@ fun errorCheckEndFrameSanityChecks() {
     // 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)
         if (g.currentWindowStack.size > 1) {
+            val window = g.currentWindowStack.last().window // <-- This window was not Ended!
             assert(g.currentWindowStack.size == 1) { "Mismatched Begin/BeginChild vs End/EndChild calls: did you forget to call End/EndChild?" }
+//            IM_UNUSED(window);
             while (g.currentWindowStack.size > 1)
                 end()
         } else