[KBM] Fixing text replacement bug (#46069)

There is a bug now where text replacement is causing the app to crash.
Wrapping those blocks in try catch so the worker stays alive.

src/modules/keyboardmanager/common/Helpers.cpp

@@ -428,20 +428,20 @@ namespace Helpers
     {
         while (true)
         {
-            std::wstring text;
-            {
-                std::unique_lock<std::mutex> lock(s_queueMutex);
-                s_queueCV.wait(lock, [] { return !s_clipboardQueue.empty() || s_shutdown.load(); });
-                if (s_shutdown.load())
-                {
-                    break;
-                }
-                text = std::move(s_clipboardQueue.front());
-                s_clipboardQueue.pop();
-            }
-
             try
             {
+                std::wstring text;
+                {
+                    std::unique_lock<std::mutex> lock(s_queueMutex);
+                    s_queueCV.wait(lock, [] { return !s_clipboardQueue.empty() || s_shutdown.load(); });
+                    if (s_shutdown.load())
+                    {
+                        break;
+                    }
+                    text = std::move(s_clipboardQueue.front());
+                    s_clipboardQueue.pop();
+                }
+
                 // Snapshot current clipboard state
                 bool hadOriginalText = false;
                 std::wstring originalClipboardText;
@@ -490,22 +490,15 @@ namespace Helpers
                     }
                 }
             }
-            catch (const std::exception& ex)
-            {
-                OutputDebugStringA("KBM ClipboardWorker exception: ");
-                OutputDebugStringA(ex.what());
-                OutputDebugStringA("\n");
-            }
             catch (...)
             {
-                OutputDebugStringA("KBM ClipboardWorker unknown exception\n");
+                OutputDebugStringA("KBM ClipboardWorker exception caught, continuing\n");
             }
         }
     }
 
-    // Function to send text via clipboard paste (Ctrl+V).
+    // Inner implementation that may throw C++ exceptions.
-    // Saves the previous clipboard content and restores it asynchronously.
+    static bool SendTextViaClipboardImpl(const std::wstring& text)
-    bool SendTextViaClipboard(const std::wstring& text)
     {
         // Lazily start the worker on first use.
         std::call_once(s_workerInitFlag, [] {
@@ -524,7 +517,7 @@ namespace Helpers
         });
 
         // Enqueue the text and return immediately so we never block the
-        // low-level keyboard hook (WH_KEYBOARD_LL).  
+        // low-level keyboard hook (WH_KEYBOARD_LL).
         {
             std::lock_guard<std::mutex> lock(s_queueMutex);
             if (!s_clipboardQueue.empty())
@@ -538,6 +531,24 @@ namespace Helpers
         return true;
     }
 
+    // Function to send text via clipboard paste (Ctrl+V).
+    // Saves the previous clipboard content and restores it asynchronously.
+    // This function MUST NOT throw — it's called from noexcept hook handlers.
+    // We use __try/__except (SEH) because C++ try/catch may be optimized away
+    // in Release builds when the caller is noexcept.
+    bool SendTextViaClipboard(const std::wstring& text) noexcept
+    {
+        __try
+        {
+            return SendTextViaClipboardImpl(text);
+        }
+        __except (EXCEPTION_EXECUTE_HANDLER)
+        {
+            OutputDebugStringA("KBM SendTextViaClipboard SEH exception caught\n");
+            return false;
+        }
+    }
+
     // Function to filter the key codes for artificial key codes
     int32_t FilterArtificialKeys(const int32_t& key)
     {

src/modules/keyboardmanager/common/Helpers.h

@@ -42,7 +42,7 @@ namespace Helpers
     void SetTextKeyEvents(std::vector<INPUT>& keyEventArray, const std::wstring& remapping);
 
     // Function to send text via clipboard paste (Ctrl+V). Saves and restores previous clipboard content.
-    bool SendTextViaClipboard(const std::wstring& text);
+    bool SendTextViaClipboard(const std::wstring& text) noexcept;
 
     // Function to return window handle for a full screen UWP app
     HWND GetFullscreenUWPWindowHandle();