Code optimization and bug fixes.

tests/edit_fixture.c

@@ -22,6 +22,29 @@ static HWND editor, password, history;
 static int step;
 static int history_position;
 
+static DWORD WINAPI update_history_from_worker(void *window) {
+  SendMessageW((HWND)window, WM_SETTEXT, 0, (LPARAM)L"unrelated worker update");
+  return 0;
+}
+
+static void unrelated_history_update(void) {
+  HANDLE thread = CreateThread(NULL, 0, update_history_from_worker, history, 0, NULL);
+  if (!thread) ExitProcess(2);
+  // Dispatch sent messages without removing a queued message, as GetMessage
+  // does while waiting for input. Do not rely on worker/timer scheduling.
+  for (;;) {
+    DWORD result = MsgWaitForMultipleObjects(1, &thread, FALSE, 2000, QS_SENDMESSAGE);
+    if (result == WAIT_OBJECT_0) break;
+    if (result != WAIT_OBJECT_0 + 1) ExitProcess(2);
+    MSG message;
+    PeekMessageW(&message, NULL, 0, 0, PM_NOREMOVE);
+  }
+  CloseHandle(thread);
+  WCHAR text[64];
+  GetWindowTextW(history, text, 64);
+  if (lstrcmpW(text, L"unrelated worker update")) ExitProcess(2);
+}
+
 // Model MUSHclient's PreTranslateMessage: consume queued arrows before the
 // Edit procedure, then use SetWindowText and SetSel to recall a command.
 static BOOL history_input(const MSG *message) {
@@ -29,7 +52,10 @@ static BOOL history_input(const MSG *message) {
       (message->wParam != VK_UP && message->wParam != VK_DOWN)) return FALSE;
   if (message->wParam == VK_UP && history_position < 2) ++history_position;
   else if (message->wParam == VK_DOWN && history_position > 0) --history_position;
-  else return TRUE;
+  else {
+    if (step == 49) unrelated_history_update();
+    return TRUE;
+  }
   const WCHAR *commands[] = {L"", L"history north", L"history south"};
   SetWindowTextW(history, commands[history_position]);
   int length = GetWindowTextLengthW(history);
@@ -239,10 +265,14 @@ static LRESULT CALLBACK window_proc(HWND window, UINT message, WPARAM wp, LPARAM
       PostMessageW(history, WM_KEYDOWN, VK_DOWN, 1); // no history change
       break;
     case 50:
+      // The silent worker update must still refresh the navigation snapshot.
+      PostMessageW(history, WM_KEYDOWN, VK_RIGHT, 1);
+      break;
+    case 51:
       SendMessageW(history, EM_SETPASSWORDCHAR, L'*', 0);
       PostMessageW(history, WM_KEYDOWN, VK_UP, 1);
       break;
-    case 51:
+    case 52:
       SetFocus(password);
       SendMessageW(history, EM_SETPASSWORDCHAR, 0, 0);
       PostMessageW(history, WM_KEYDOWN, VK_UP, 1); // background recall