[Bug 54407] New: user32:msg - test_SendMessage_other_thread() sometimes gets a bad WM_USER message sequence in Wine

[WineHQ Bugzilla]

https://bugs.winehq.org/show_bug.cgi?id=54407

Bug ID: 54407
           Summary: user32:msg - test_SendMessage_other_thread() sometimes
                    gets a bad WM_USER message sequence in Wine
           Product: Wine
           Version: unspecified
          Hardware: x86-64
                OS: Linux
            Status: NEW
          Severity: normal
          Priority: P2
         Component: user32
          Assignee: [e-mail]
          Reporter: [e-mail]
      Distribution: ---

user32:msg - test_SendMessage_other_thread() sometimes gets a bad WM_USER
message sequence in Wine:

msg.c:19187: Test failed: SendMessage from other thread 1: 1: the msg 0x0400
was expected, but got msg 0x0403 instead
msg.c:19187: Test failed: SendMessage from other thread 1: 2: the msg sequence
is not complete: expected 0000 - actual 0400
msg.c:19201: Test failed: wrong status 00080000
msg.c:19207: Test failed: SendMessage from other thread 3: 0: the msg 0x0403
was expected, but got msg 0x0401 instead
msg.c:19207: Test failed: SendMessage from other thread 3: 1: the msg sequence
is not complete: expected 0401 - actual 0000

See https://test.winehq.org/data/patterns.html#user32:msg

A somewhat similar issue has been happening for some time on Windows 7 (see bug
53434).
This one started happening about twice per month in Wine on 2022-10-14
(debian11-win32).

[Bug 54407] user32:msg - test_SendMessage_other_thread() sometimes gets a bad WM_USER message sequence in Wine

[WineHQ Bugzilla]

https://bugs.winehq.org/show_bug.cgi?id=54407

François Gouget  changed:

What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |source, testcase

[Bug 54407] user32:msg - test_SendMessage_other_thread() sometimes gets a bad WM_USER message sequence in Wine

[WineHQ Bugzilla]

https://bugs.winehq.org/show_bug.cgi?id=54407

--- Comment #1 from Esme Povirk  ---
Sounds like a synchronization failure? WM_USER+3 sent too early?

OK, so based on SendMessage_thread_2 being a todo_wine, we know we're dealing
with SendMessage_thread_1. We also know that the WM_USER+3 is processed inside
the GetMessageA call in test_SendMessage_other_thread. So it seems that after
WM_USER+2 is processed, the background thread is able to send out the WM_USER+3
before the main thread is able to remove the posted WM_USER from the queue and
return from GetMessageA.

I don't see anything that would prevent this from happening, so it's not clear
to me whether this is intended to test some subtle timing thing, or it's just a
race condition in the test.

[Bug 54407] user32:msg - test_SendMessage_other_thread() sometimes gets a bad WM_USER message sequence in Wine

[WineHQ Bugzilla]

https://bugs.winehq.org/show_bug.cgi?id=54407

--- Comment #2 from Esme Povirk  ---
This entire test seems to make a lot of assumptions about how long things take,
and I'm not sure if that's really fixable.