bug#39962: 27.0.90; Crash in Emacs 27.0.90

[Eli Zaretskii]

> From: Pieter van Oostrum <pieter-l@vanoostrum.org>
> Cc: Eli Zaretskii <eliz@gnu.org>,  39962@debbugs.gnu.org,  eggert@cs.ucla.edu
> Date: Sat, 21 Mar 2020 22:22:32 +0100
> 
> I got the old Marker corruption back.
> 
> 
> insdel.c:295: Emacs fatal error: assertion failed: m->bytepos >= m->charpos 
> && m->bytepos - m->charpos <= Z_BYTE - Z
> 
> Thread 3 hit Breakpoint 1, terminate_due_to_signal (sig=6, 
> --Type <RET> for more, q to quit, c to continue without paging--
>     backtrace_limit=2147483647) at emacs.c:371
> 371     signal (sig, SIG_DFL);
> (gdb) bt
> #0  terminate_due_to_signal (sig=6, backtrace_limit=2147483647) at emacs.c:371
> #1  0x00000001002a4a1b in die (
>     msg=0x10050ff60 "m->bytepos >= m->charpos && m->bytepos - m->charpos <= 
> Z_BYTE - Z", file=0x10050fde3 "insdel.c", line=295) at alloc.c:7264
> #2  0x0000000100233a24 in adjust_markers_for_insert (from=529592, 
>     from_byte=529598, to=529594, to_byte=529600, before_markers=false)
>     at insdel.c:294

Can you show the offending data that failed the assertion?

Also, would it be possible for you to look into the related data, as I
suggested several messages ago, and show what you find?  It might give
us some ideas for further debugging.

Thanks.