[PATCH v2 2/2] win32u: Put the message in the queue when callback pointer is NULL and callback data is 1.

[Zhiyi Zhang]

From: Zhiyi Zhang

This is an undocumented behavior needed by React Native apps, based on Nikolay's findings.
---
 dlls/user32/tests/msg.c | 10 ++++------
 dlls/win32u/message.c   |  4 +++-
 2 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/dlls/user32/tests/msg.c b/dlls/user32/tests/msg.c
index 24be627a78d..696cf41505e 100644
--- a/dlls/user32/tests/msg.c
+++ b/dlls/user32/tests/msg.c
@@ -16532,18 +16532,18 @@ static void test_nullCallback(void)
     flush_sequence();
     ret = SendMessageCallbackA(hwnd, WM_USER, 0, 0, NULL, 1);
     ok(ret, "SendMessageCallbackA failed, error %ld.", GetLastError());
-    ok_sequence(WmEmptySeq, "WM_USER with NULL callback", TRUE);
+    ok_sequence(WmEmptySeq, "WM_USER with NULL callback", FALSE);
     flush_events();
-    ok_sequence(WmUserSeq, "WM_USER with NULL callback after flushing events", TRUE);
+    ok_sequence(WmUserSeq, "WM_USER with NULL callback after flushing events", FALSE);

/* NULL callback and data being 1 with SendMessageCallbackW(). The result suggests that the
      * message is not directly sent to the window */
     flush_sequence();
     ret = SendMessageCallbackW(hwnd, WM_USER, 0, 0, NULL, 1);
     ok(ret, "SendMessageCallbackW failed, error %ld.", GetLastError());
-    ok_sequence(WmEmptySeq, "WM_USER with NULL callback", TRUE);
+    ok_sequence(WmEmptySeq, "WM_USER with NULL callback", FALSE);
     flush_events();
-    ok_sequence(WmUserSeq, "WM_USER with NULL callback after flushing events", TRUE);
+    ok_sequence(WmUserSeq, "WM_USER with NULL callback after flushing events", FALSE);

/* NULL callback and data being 2 with SendMessageCallbackA() */
     flush_sequence();
@@ -16562,7 +16562,6 @@ static void test_nullCallback(void)
     ret = SendMessageCallbackA(hwnd, WM_USER, 0, 0, NULL, 1);
     ok(ret, "SendMessageCallbackA failed, error %ld.", GetLastError());
     status = GetQueueStatus(QS_ALLINPUT);
-    todo_wine
     ok(HIWORD(status) & QS_SENDMESSAGE && LOWORD(status) & QS_SENDMESSAGE,
        "Got unexpected status %#lx.\n", status);

@@ -16571,7 +16570,6 @@ static void test_nullCallback(void)
     ret = SendMessageCallbackW(hwnd, WM_USER, 0, 0, NULL, 1);
     ok(ret, "SendMessageCallbackW failed, error %ld.", GetLastError());
     status = GetQueueStatus(QS_ALLINPUT);
-    todo_wine
     ok(HIWORD(status) & QS_SENDMESSAGE && LOWORD(status) & QS_SENDMESSAGE,
        "Got unexpected status %#lx.\n", status);

diff --git a/dlls/win32u/message.c b/dlls/win32u/message.c
index 2a824dbdab3..e64e8213f93 100644
--- a/dlls/win32u/message.c
+++ b/dlls/win32u/message.c
@@ -4189,7 +4189,9 @@ static BOOL process_message( struct send_message_info *info, DWORD_PTR *res_ptr,
     thread_info->msg_source = msg_source_unavailable;
     spy_enter_message( SPY_SENDMESSAGE, info->hwnd, info->msg, info->wparam, info->lparam );

-    if (info->dest_tid != GetCurrentThreadId())
+    if (info->dest_tid != GetCurrentThreadId() ||
+        /* undocumented behavior when callback pointer is NULL and data is 1. See test_nullCallback(). */
+        (info->type == MSG_CALLBACK && !info->callback && info->data == 1))
     {
         if (dest_pid != GetCurrentProcessId() && (info->type == MSG_ASCII || info->type == MSG_UNICODE))
             info->type = MSG_OTHER_PROCESS;