[XeTeX] xelatex math problem with sqrt

[Christian Schenk]

Jonathan Kew wrote:
> It shouldn't be necessary to initialize the font_mapping array with  
> zeros, because whenever a font is loaded, the corresponding entry in  
> font_mapping should be specifically set to the newly-loaded mapping  
> pointer, or to NULL if no mapping was specified.
> 
> This happens in a couple of ways, depending on the kind of font: for  
> "native" fonts loaded via find_native_font, the mapping is returned  
> to the WEB code in a global variable, which is initialized to NULL in  
> findnativefont() in XeTeX.c. And for TFM fonts, the function  
> loadtfmfontmapping() should return either a valid mapping pointer, or  
> NULL.
> 
> I'll re-examine the possible code paths to see if there's a  
> possibility of the value being left uninitialized; alternatively, are  
> there changes in MiKTeX that mean the initialization to NULL gets  
> missed in some case?

Not that I know of. I will take a closer look at the MiKTeX change file. 
  IIRC, the crash occured in TECkit_ConvertBuffer with 
applytfmfontmapping on the call stack.