v2 conhost crash with SetConsoleScreenBufferInfoEx calls

[rprichard]

• Your Windows build number: [Version 10.0.17760.1]

What you're doing and what's happening: (Copy & paste specific commands and their output, or include screen shots)

Using SetConsoleScreenBufferInfoEx to make the console buffer and window smaller, simultaneously, can crash the v2 conhost with a recent Insiders build.

Steps:

1. Open a cmd/powershell console window.
2. Open the console properties and uncheck the "Layout > Wrap text output on resize" option.
3. Run the test program I included.
4. The console window disappears.

What's wrong / what should be happening instead:

SetConsoleScreenBufferInfoEx shouldn't crash. The text Hello? should appear, and the console should return control to cmd/powershell.

Aside 1: I don't think this affects winpty at all.
Aside 2: SetConsoleScreenBufferInfoEx seems to handle srWindow differently than both SetConsoleWindowInfo and GetConsoleScreenBufferInfoEx. It tends to set the window size to 1 less width/height than the requested size, so a pair of calls to GetConsoleScreenBufferInfoEx and SetConsoleScreenBufferInfoEx shrinks the console window.

Test program

#include <windows.h>
#include <stdio.h>

int main(int argc, char *argv[]) {

    HANDLE conout = GetStdHandle(STD_OUTPUT_HANDLE);
    CONSOLE_SCREEN_BUFFER_INFOEX info = { sizeof(info) };
    GetConsoleScreenBufferInfoEx(conout, &info);

    info.dwSize.X = 120;
    info.dwSize.Y = 5000;
    info.srWindow.Left = info.srWindow.Top = 0;
    info.srWindow.Right = 121;
    info.srWindow.Bottom = 26;
    SetConsoleScreenBufferInfoEx(conout, &info);

    SetConsoleCursorPosition(conout, COORD { 0, 4000 });

    info.dwSize.X = 80;
    info.dwSize.Y = 20;
    info.srWindow.Right = 41;
    info.srWindow.Bottom = 11;
    SetConsoleScreenBufferInfoEx(conout, &info);

    printf("Hello?\n");

    return 0;
}

[zadjii-msft]

Thanks for the bug report, I've filed msft:19013486 to make sure this gets fixed ASAP :)

[miniksa]

I'm not able to reproduce this issue anymore. Perhaps we fixed it?

If it's still crashing for you, can you try to find the report ID so I can maybe correlate it?
It should be in the Event Viewer under Windows Logs > Application.

I believe it's Event ID 1000 for Application Error (and should contain conhost.exe as the faulting application path with a report ID GUID that you can give to me).

[DHowett-MSFT]

Closing this for now. If you can get the report ID from a recent repro of this crash, we'd love to take a look. Thanks!