new_editor: stabilize multi-window host lifecycle

new_editor/app/Composition/EditorWindowWorkspaceStore.cpp

@@ -1,6 +1,9 @@
 #include "Composition/EditorWindowWorkspaceStore.h"
 
+#include <XCEditor/Foundation/UIEditorRuntimeTrace.h>
+
 #include <algorithm>
+#include <sstream>
 #include <utility>
 
 namespace XCEngine::UI::Editor::App {
@@ -39,6 +42,24 @@ void UpsertWindowState(
     windowSet.windows.push_back(std::move(windowState));
 }
 
+std::string DescribeWindowSetState(const UIEditorWindowWorkspaceSet& windowSet) {
+    std::ostringstream stream = {};
+    stream << "primary='" << windowSet.primaryWindowId
+           << "' active='" << windowSet.activeWindowId
+           << "' count=" << windowSet.windows.size()
+           << " windows=[";
+    bool first = true;
+    for (const UIEditorWindowWorkspaceState& state : windowSet.windows) {
+        if (!first) {
+            stream << ',';
+        }
+        first = false;
+        stream << state.windowId;
+    }
+    stream << ']';
+    return stream.str();
+}
+
 } // namespace
 
 EditorWindowWorkspaceStore::EditorWindowWorkspaceStore(UIEditorPanelRegistry panelRegistry)
@@ -133,12 +154,24 @@ void EditorWindowWorkspaceStore::ReplaceWindowSet(UIEditorWindowWorkspaceSet win
 }
 
 void EditorWindowWorkspaceStore::RemoveWindow(std::string_view windowId, bool primary) {
+    const std::string beforeState = DescribeWindowSetState(m_windowSet);
     if (m_windowSet.windows.empty()) {
+        AppendUIEditorRuntimeTrace(
+            "window-close",
+            "store remove skipped windowId='" + std::string(windowId) +
+                "' primaryArg=" + (primary ? "1" : "0") +
+                " stateBefore=" + beforeState);
         return;
     }
 
     if (primary || m_windowSet.primaryWindowId == windowId) {
         m_windowSet = {};
+        AppendUIEditorRuntimeTrace(
+            "window-close",
+            "store remove cleared all windows windowId='" + std::string(windowId) +
+                "' primaryArg=" + (primary ? "1" : "0") +
+                " stateBefore=" + beforeState +
+                " stateAfter=" + DescribeWindowSetState(m_windowSet));
         return;
     }
 
@@ -164,6 +197,13 @@ void EditorWindowWorkspaceStore::RemoveWindow(std::string_view windowId, bool pr
         FindUIEditorWindowWorkspaceState(m_windowSet, m_windowSet.activeWindowId) == nullptr) {
         m_windowSet.activeWindowId = ResolveFallbackWindowId(m_windowSet);
     }
+
+    AppendUIEditorRuntimeTrace(
+        "window-close",
+        "store remove completed windowId='" + std::string(windowId) +
+            "' primaryArg=" + (primary ? "1" : "0") +
+            " stateBefore=" + beforeState +
+            " stateAfter=" + DescribeWindowSetState(m_windowSet));
 }
 
 } // namespace XCEngine::UI::Editor::App