[metapost] segfault on incorrect input

[Hans Hagen]

On 5/1/2021 9:46 AM, Martin Budaj wrote:
> Hi,
> 
> incidentally I've found that metapost segfaults on the following 
> (incorrect) input:
> 
> nonstopmode;
> % erroneously, a-b written instead of a_b
> def a-b = a-c enddef;
> a-b;
> end
> 
> The output is:
> 
> l.4 def a-
>            b = a-c enddef;
> Segmentation fault
> 
> Tested on 2.00 (TeX Live 2020/Debian) and 2.01 (TeX Live 2021/W32TeX).
> 
> Metafont processes the file as expected, with a regular error message.
Luigi,

It also crashes in luatex but not in luametatex so it might be somewhere 
in the input buffer or error reporting part as that's done differently.

b = a-c enddef; a-b; ;

The bit after the ; is not seen in the crash.

Hans



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