Maximizing/Restoring when the alt buffer is active crashes conhost #1206

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1. Dustin L. Howett (MSFT) (DHowett-MSFT)

   added

   Product-ConhostFor issues in the Console codebaseFor issues in the Console codebase

   Area-OutputRelated to output processing (inserting text into buffer, retrieving buffer text, etc.)Related to output processing (inserting text into buffer, retrieving buffer text, etc.)

   Issue-BugIt either shouldn't be doing this or needs an investigation.It either shouldn't be doing this or needs an investigation.

   Severity-CrashCrashes are real bad news.Crashes are real bad news.

   on Jun 11, 2019
2. Dustin L. Howett (MSFT) (DHowett-MSFT)

   added this to the 20H1 milestone on Jun 11, 2019
3. ghost added

   Needs-TriageIt's a new issue that the core contributor team needs to triage at the next triage meetingIt's a new issue that the core contributor team needs to triage at the next triage meeting

   on Jun 11, 2019
4. Dustin L. Howett (MSFT) (DHowett-MSFT)

   removed

   Needs-TriageIt's a new issue that the core contributor team needs to triage at the next triage meetingIt's a new issue that the core contributor team needs to triage at the next triage meeting

   on Jun 11, 2019
5. DHowett-MSFT commented on Jun 11, 2019

   

   Dustin L. Howett (MSFT) (DHowett-MSFT)

   on Jun 11, 2019

   ContributorAuthor

   More actions

    	OpenConsole.exe!wil::details::in1diag5::_Throw_Hr(void * callerReturnAddress, unsigned int lineNumber, const char * fileName, const char * functionName, const char * code, HRESULT hr) Line 4937	C++
    	OpenConsole.exe!wil::details::in1diag5::Throw_HrIf(void * callerReturnAddress, unsigned int lineNumber, const char * fileName, const char * functionName, const char * code, HRESULT hr, bool condition) Line 5041	C++
    	OpenConsole.exe!TextBufferCellIterator::TextBufferCellIterator(const TextBuffer & buffer, _COORD pos, const Microsoft::Console::Types::Viewport limits) Line 43	C++
    	OpenConsole.exe!TextBuffer::GetCellDataAt(const _COORD at, const Microsoft::Console::Types::Viewport limit) Line 169	C++
    	OpenConsole.exe!Microsoft::Console::Render::Renderer::_PaintBufferOutput(Microsoft::Console::Render::IRenderEngine * const pEngine) Line 579	C++
    	OpenConsole.exe!Microsoft::Console::Render::Renderer::_PaintFrameForEngine(Microsoft::Console::Render::IRenderEngine * const pEngine) Line 119	C++
    	OpenConsole.exe!Microsoft::Console::Render::Renderer::PaintFrame() Line 68	C++
    	OpenConsole.exe!Microsoft::Console::Render::RenderThread::_ThreadProc() Line 168	C++
    	OpenConsole.exe!Microsoft::Console::Render::RenderThread::s_ThreadProc(void * lpParameter) Line 151	C++
   
6. Dustin L. Howett (MSFT) (DHowett-MSFT)

   added

   Area-RenderingText rendering, emoji, complex glyph & font-fallback issuesText rendering, emoji, complex glyph & font-fallback issues

   and removed

   Area-OutputRelated to output processing (inserting text into buffer, retrieving buffer text, etc.)Related to output processing (inserting text into buffer, retrieving buffer text, etc.)

   on Jun 11, 2019
7. Mike Griese (zadjii-msft)

   self-assigned this

   on Aug 27, 2019
8. zadjii-msft commented on Sep 3, 2019

   

   Mike Griese (zadjii-msft)

   on Sep 3, 2019

   Member

   More actions

   This only repros if "Disable scroll forward" is enabled.

   This surprises me, considering the alt buffer doesn't need to do anything with _virtualBottom, but something's definitely busted there.
9. zadjii-msft commented on Sep 3, 2019

   

   Mike Griese (zadjii-msft)

   on Sep 3, 2019

   Member

   More actions

   This code looks bad: SCREEN_INFORMATION::_InternalSetViewportSize

   > OpenConsole!SCREEN_INFORMATION::_InternalSetViewportSize+0x5ca [...OpenConsole\src\host\screenInfo.cpp @ 1241] 
     OpenConsole!SCREEN_INFORMATION::_AdjustViewportSize+0x157 [...\OpenConsole\src\host\screenInfo.cpp @ 1297] 
     OpenConsole!SCREEN_INFORMATION::ProcessResizeWindow+0x14c [...\OpenConsole\src\host\screenInfo.cpp @ 887] 
     OpenConsole!Microsoft::Console::Interactivity::Win32::Window::_HandleWindowPosChanged+0x135 [...\OpenConsole\src\interactivity\win32\WindowProc.cpp @ 812] 
     OpenConsole!Microsoft::Console::Interactivity::Win32::Window::ConsoleWindowProc+0x101c [...\OpenConsole\src\interactivity\win32\WindowProc.cpp @ 478] 
   

       if (gci.IsTerminalScrolling() && newViewport.Height() != _viewport.Height())
       {
           const short newTop = static_cast<short>(std::max(0, _virtualBottom - (newViewport.Height() - 1)));
   
           newViewport = Viewport::FromDimensions(COORD({ newViewport.Left(), newTop }), newViewport.Dimensions());
       }
   

   During the resize down, we're resizing the alt buffer here. Prior to the newViewport = Viewport::FromDimensions(... line, members have the following values:

   Variable	value
   newTop	76
   _virtualBottom	105
   newViewport	{LT(0, 0) RB(119, 29) [120 x 30]}
   _viewport	{LT(0, 0) RB(370, 105) [371 x 106]}

   Looks like we're trying to set the top of the new viewport so that the virtual bottom stays anchored to the new viewport's bottom. However, this only makes sense when the viewport is getting bigger, not when it's getting smaller. In that scenario, we'll end up setting the top to somewhere in the middle of the buffer, and then be real confused by the next paint.
10. Mike Griese (zadjii-msft)

    added a commit that references this issue on Sep 3, 2019

    add a test for #1206

    4e58187
11. ghost added

    In-PRThis issue has a related PRThis issue has a related PR

    on Sep 5, 2019
12. Mike Griese (zadjii-msft)

    closed this as completedin #2666on Sep 5, 2019
13. Mike Griese (zadjii-msft)

    added a commit that references this issue on Sep 5, 2019

    Don't crash when restore-down'ing the alt buffer (#2666)

    ...

    This issue will close once commit c58033c is merged into the 'main' branch.

    c58033c
14. ghost added

    Needs-Tag-FixDoesn't match tag requirementsDoesn't match tag requirements

    on Sep 5, 2019
15. ghost removed

    In-PRThis issue has a related PRThis issue has a related PR

    on Sep 5, 2019
16. ghost added

    Resolution-Fix-CommittedFix is checked in, but it might be 3-4 weeks until a release.Fix is checked in, but it might be 3-4 weeks until a release.

    on Sep 5, 2019
17. Dustin L. Howett (MSFT) (DHowett-MSFT)

    added

    Priority-1A description (P1)A description (P1)

    on Sep 5, 2019
18. ghost removed

    Needs-Tag-FixDoesn't match tag requirementsDoesn't match tag requirements

    on Sep 5, 2019
19. Dustin L. Howett (MSFT) (DHowett-MSFT)

    added a commit that references this issue on Sep 23, 2019

    Don't crash when restore-down'ing the alt buffer (#2666)

    ...

    This issue will close once commit 1284fca is merged into the 'main' branch.

    1284fca
21. ghost added a commit that references this issue on May 2, 2022

    Prevent the virtual viewport bottom being updated incorrectly (#12972)

    ...

    e3f4ec8