[PATCH 0/2] MR8702: user32/tests: Add more SendMessageCallbackA/W() tests with NULL callback.

[Zhiyi Zhang (＠zhiyi)]

For React Native.

-- 
https://gitlab.winehq.org/wine/wine/-/merge_requests/8702

[PATCH 1/2] user32/tests: Add more SendMessageCallbackA/W() tests with NULL callback.

[Zhiyi Zhang]

From: Zhiyi Zhang <zzhang(a)codeweavers.com>

The tests are mainly to show that SendMessageCallbackA/W() with NULL callback pointer and callback
data being 1 causes message to be posted to window, even when the window is created in the same thread.
---
 dlls/user32/tests/msg.c | 39 ++++++++++++++++++++++++++++++++++++++-
 1 file changed, 38 insertions(+), 1 deletion(-)

diff --git a/dlls/user32/tests/msg.c b/dlls/user32/tests/msg.c
index 80d900baa1c..1c2d61c7781 100644
--- a/dlls/user32/tests/msg.c
+++ b/dlls/user32/tests/msg.c
@@ -16499,6 +16499,12 @@ static void test_EndDialog(void)
     UnregisterClassA(cls.lpszClassName, cls.hInstance);
 }
 
+static const struct message WmUserSeq[] =
+{
+    { WM_USER, sent },
+    { 0 }
+};
+
 static void test_nullCallback(void)
 {
     HWND hwnd;
@@ -16507,8 +16513,39 @@ static void test_nullCallback(void)
                            100, 100, 200, 200, 0, 0, 0, NULL);
     ok (hwnd != 0, "Failed to create overlapped window\n");
 
-    SendMessageCallbackA(hwnd,WM_NULL,0,0,NULL,0);
+    /* NULL callback and data being 0 */
+    flush_sequence();
+    SendMessageCallbackA(hwnd, WM_USER, 0, 0, NULL, 0);
+    ok_sequence(WmUserSeq, "WM_USER with NULL callback", FALSE);
+
+    flush_sequence();
+    SendMessageCallbackW(hwnd, WM_USER, 0, 0, NULL, 0);
+    ok_sequence(WmUserSeq, "WM_USER with NULL callback", FALSE);
+
+    /* NULL callback and data being 1. The result suggests that the message is posted to the window */
+    flush_sequence();
+    SendMessageCallbackA(hwnd, WM_USER, 0, 0, NULL, 1);
+    ok_sequence(WmEmptySeq, "WM_USER with NULL callback", TRUE);
     flush_events();
+    ok_sequence(WmUserSeq, "WM_USER with NULL callback after flushing events", TRUE);
+
+    /* NULL callback and data being 1. The result suggests that the message is posted to the window */
+    flush_sequence();
+    SendMessageCallbackW(hwnd, WM_USER, 0, 0, NULL, 1);
+    ok_sequence(WmEmptySeq, "WM_USER with NULL callback", TRUE);
+    flush_events();
+    ok_sequence(WmUserSeq, "WM_USER with NULL callback after flushing events", TRUE);
+
+    /* NULL callback and data being 2 */
+    flush_sequence();
+    SendMessageCallbackA(hwnd, WM_USER, 0, 0, NULL, 2);
+    ok_sequence(WmUserSeq, "WM_USER with NULL callback", FALSE);
+
+    /* NULL callback and data being 2 */
+    flush_sequence();
+    SendMessageCallbackW(hwnd, WM_USER, 0, 0, NULL, 2);
+    ok_sequence(WmUserSeq, "WM_USER with NULL callback", FALSE);
+
     DestroyWindow(hwnd);
 }
 
-- 
GitLab


https://gitlab.winehq.org/wine/wine/-/merge_requests/8702

[PATCH 2/2] user32: Post message when callback pointer is NULL and callback data is 1 in SendMessageCallbackA/W().

[Zhiyi Zhang]

From: Zhiyi Zhang <zzhang(a)codeweavers.com>

This is an undocumented behavior needed by React Native apps, based on Nikolay's findings.
---
 dlls/user32/message.c   | 7 +++++++
 dlls/user32/tests/msg.c | 8 ++++----
 2 files changed, 11 insertions(+), 4 deletions(-)

diff --git a/dlls/user32/message.c b/dlls/user32/message.c
index 205d3e01c02..3b541959faf 100644
--- a/dlls/user32/message.c
+++ b/dlls/user32/message.c
@@ -640,6 +640,9 @@ BOOL WINAPI SendMessageCallbackA( HWND hwnd, UINT msg, WPARAM wparam, LPARAM lpa
 {
     struct send_message_callback_params params = { .callback = callback, .data = data };
 
+    if (!callback && data == 1)
+        return PostMessageA( hwnd, msg, wparam, lparam );
+
     if (!WIN_IsCurrentThread( hwnd ) && !map_wparam_AtoW( msg, &wparam, WMCHAR_MAP_SENDMESSAGE ))
         return FALSE;
 
@@ -654,6 +657,10 @@ BOOL WINAPI SendMessageCallbackW( HWND hwnd, UINT msg, WPARAM wparam, LPARAM lpa
                                   SENDASYNCPROC callback, ULONG_PTR data )
 {
     struct send_message_callback_params params = { .callback = callback, .data = data };
+
+    if (!callback && data == 1)
+        return PostMessageW( hwnd, msg, wparam, lparam );
+
     return NtUserMessageCall( hwnd, msg, wparam, lparam, ¶ms, NtUserSendMessageCallback, FALSE );
 }
 
diff --git a/dlls/user32/tests/msg.c b/dlls/user32/tests/msg.c
index 1c2d61c7781..9089e96aa84 100644
--- a/dlls/user32/tests/msg.c
+++ b/dlls/user32/tests/msg.c
@@ -16525,16 +16525,16 @@ static void test_nullCallback(void)
     /* NULL callback and data being 1. The result suggests that the message is posted to the window */
     flush_sequence();
     SendMessageCallbackA(hwnd, WM_USER, 0, 0, NULL, 1);
-    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. The result suggests that the message is posted to the window */
     flush_sequence();
     SendMessageCallbackW(hwnd, WM_USER, 0, 0, NULL, 1);
-    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 */
     flush_sequence();
-- 
GitLab

https://gitlab.winehq.org/wine/wine/-/merge_requests/8702

[Dmitry Timoshkov (＠dmitry)]

What's the reason for adding duplicate tests?

-- 
https://gitlab.winehq.org/wine/wine/-/merge_requests/8702#note_111952

[Dmitry Timoshkov (＠dmitry)]

Also, it would be interesting to test the queue status.

-- 
https://gitlab.winehq.org/wine/wine/-/merge_requests/8702#note_111953

[Zhiyi Zhang (＠zhiyi)]

On Mon Aug  4 07:36:35 2025 +0000, Dmitry Timoshkov wrote:
> What's the reason for adding duplicate tests?
> Both SendMessageCallbackA() and SendMessageCallbackW() are being tested. The main purpose is to test an undocumented behavior, so we need to know that it's not limited only to the A/W() variant.

-- 
https://gitlab.winehq.org/wine/wine/-/merge_requests/8702#note_111954

[Zhiyi Zhang (＠zhiyi)]

On Mon Aug  4 07:36:35 2025 +0000, Dmitry Timoshkov wrote:
> Also, it would be interesting to test the queue status.
> Could you please elaborate on the queue status you would like me to test? I've added the message sequence tests.

-- 
https://gitlab.winehq.org/wine/wine/-/merge_requests/8702#note_111955

[Dmitry Timoshkov (＠dmitry)]

On Mon Aug  4 07:36:35 2025 +0000, Zhiyi Zhang wrote:
> Could you please elaborate on the queue status you would like me to
> test? I've added the message sequence tests.
> The queue status would confirm that the message is supposed to be posted and not sent.

-- 
https://gitlab.winehq.org/wine/wine/-/merge_requests/8702#note_111957

[Dmitry Timoshkov (＠dmitry)]

On Mon Aug  4 07:36:34 2025 +0000, Zhiyi Zhang wrote:
> Both SendMessageCallbackA() and SendMessageCallbackW() are being tested.
> The main purpose is to test an undocumented behavior, so we need to know
> that it's not limited only to the A/W() variant.
> Thanks. Probably a comment that clarifies that would be helpful.

-- 
https://gitlab.winehq.org/wine/wine/-/merge_requests/8702#note_111958

[Dmitry Timoshkov (＠dmitry)]

Also it would be interesting to test return value of SendMessageCallback().

-- 
https://gitlab.winehq.org/wine/wine/-/merge_requests/8702#note_111984