New subject: [Bug 53984] Broken minimize-restore logic in conhost.exe for all console apps

26 Nov 2022


      https://bugs.winehq.org/show_bug.cgi?id=53984
Bug ID: 53984
           Summary: Broken minimize-restore logic in conhost.exe for all
                    console apps
           Product: Wine
           Version: 7.21
          Hardware: x86-64
                OS: Linux
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: -unknown
          Assignee: wine-bugs@winehq.org
          Reporter: x1917x@gmail.com
      Distribution: ---
Created attachment 73566
  --> https://bugs.winehq.org/attachment.cgi?id=73566
Issue log for minimize-restore
There is an old bug in Wine's conhost.exe, introduced years ago. Whenever a
console window is minimized and then restored, conhost.exe creates both
vertical and horizontal scrollbars for that window, no matter that there were
no changes to that window. Bad consequence is that both of them overlap parts
of content of the console window, so now one have to actually scroll the window
to see the lines/columns covered by scrollbars.
From what I see, the bug affects all console apps, the attached log file was
taken for Wine's cmd.exe (wineconsole cmd.exe).
The root cause of the bug is that conhost.exe makes no distinction between
WM_SIZE caused by regular resize and WM_SIZE caused by minimizing. Whenever the
console window gets minimized, ShowWindow(SW_MINIMIZE) is being called for it.
Internally, Wine's show_window() calls window_min_maximize() to retrieve the
minimized window Rect. For a minimized window it fills that Rect with the size
of "iconic" window, which is determined by get_system_metrics(SM_CXMINIMIZED)
and get_system_metrics(SM_CYMINIMIZED). Not sure if it depends on the host, but
on my system it is 160 x 31. So eventually WM_SIZE(<...>, 160, 31) is being
sent to conhost.exe's window, among few other WM_-messages. As conhost.exe
makes no distinction between the different states the console window can be, it
assumes that the minimized window size (160x31) is the new real window size.
Then it tries to apply the same sequence of actions like for any received
WM_SIZE. One of them is checking if the newly resized console window is smaller
than its content. If it was the case, it creates respective horizontal/vertical
scrollbars in window.c/update_window(). So basically, conhost.exe treats every
window minimizing as a resize.
Luckily, the fix is trivial -  Wine's conhost.exe shouldn't try to resize its
window when it is minimized. There is zero point to resize a minimized window,
especially if it wasn't resized at all.
case WM_SIZE:
        if (console->window && console->window->update_state != UPDATE_BUSY)
            resize_window( console,
-->
    case WM_SIZE:
        if (console->window && console->window->update_state != UPDATE_BUSY &&
!IsIconic(console->win))
            resize_window( console,
(the patch is attached)
Please review and apply the proposed fix if it's ok (I am not a Wine
contributor - don't know how to commit to Wine, not a member of the mail list
etc).
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[Bug 53984] New: Broken minimize-restore logic in conhost.exe for all console apps