libharfbuzz0 1.7.6-1 update causing xwin-xdg-menu.exe to crash

[Jon Turney]

On 19/04/2018 22:15, Gilles Detillieux wrote:
> Has anybody else run into this problem? I've done two installations of 
> Cygwin/X on Windows 10 systems this week, and they both had problems 
> with the XWin Server dying just a few seconds after starting up. I 
> traced the problem back to xwin-xdg-menu.exe getting a Segmentation 
> fault, which then causes XWin Server to exit. I hacked an alternate 
> .startxwinrc file to prevent XWin Server from dying (it ends with a 
> "sleep infinity"), so I could debug it further.
> 
> With the XWin Server running reliably, I then ran "strace 
> xwin-xdg-menu.exe" and saw that it got a segmentation fault just after 
> reading a TTF font from the Windows Font directory (bahnschrift.ttf if 
> it matters). I noticed there were two recent library updates related to 
> font handling, so I tried back out to the previous version for each. It 
> turns out that when I reverted to version 1.7.4-1 of libharfbuzz0, 
> xwin-xdg-menu.exe stopped crashing.
> 
> If it matters, both these systems are the Fall Creator's Update (1709) 
> of Windows 10 64-bit, and I'm running the 32-bit version of Cygwin.
> 
> Hopefully someone can track down and fix this recent bug!

Thanks for reporting this.

I can reproduce this problem, but it only seems to occur with 32-bit cygwin.

(Obviously you also need a recent enough Windows 10 to have the 
Bahnschrift font)

The actual crash seems to be in fontconfig, e.g. 'fc-query 
/usr/share/fonts/microsoft/bahnschrift.ttf' fails in the same way.

I didn't get very far investigating the problem, as rebuilding the 
fontconfig package with the current toolchain seems to be enough to make 
the problem go away.

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