bug#31312: Segmentation fault with doom-emacs, NeoTree and Zoom

[Noam Postavsky <npostavs@gmail.com>]

tags 31312 + confirmed
found 31312 26.1
quit

Andrea Cardaci <cyrus.and@gmail.com> writes:

> Someone filed a bug for my repo (https://github.com/cyrus-and/zoom/issues/20)
> but I'm pretty sure it's a bug in Emacs. Unfortunately the steps to
> reproduce it involve setting up `doom-emacs` which is quite cumbersome.
>
> You can find all the details at the above link but in short using
> `doom-emacs` with Zoom and NeoTree crashes Emacs with a segmentation fault.

Reproduced with emacs-26, seems there is a window without a buffer.

../../src/buffer.h:914: Emacs fatal error: assertion failed: BUFFERP (a)

Thread 1 "emacs" hit Breakpoint 1, terminate_due_to_signal (sig=6, backtrace_limit=2147483647)
    at ../../src/emacs.c:364
364	  signal (sig, SIG_DFL);
(gdb) bt
#0  terminate_due_to_signal (sig=6, backtrace_limit=2147483647) at ../../src/emacs.c:364
#1  0x0000000000614655 in die (msg=0x74ecf9 "BUFFERP (a)", file=0x74ece6 "../../src/buffer.h", 
    line=914) at ../../src/alloc.c:7423
#2  0x000000000057a1a8 in XBUFFER (a=XIL(0)) at ../../src/buffer.h:914
#3  0x0000000000464716 in reconsider_clip_changes (w=0x60537f0) at ../../src/xdisp.c:13727
#4  0x000000000046514d in redisplay_internal () at ../../src/xdisp.c:13939
#5  0x0000000000463c16 in redisplay () at ../../src/xdisp.c:13518
#6  0x00000000005851ae in read_char (commandflag=1, map=XIL(0x5cf7503), prev_event=XIL(0), 
    used_mouse_menu=0x7fffffffe41f, end_time=0x0) at ../../src/keyboard.c:2480
#7  0x00000000005957c5 in read_key_sequence (keybuf=0x7fffffffe570, bufsize=30, prompt=XIL(0), 
    dont_downcase_last=false, can_return_switch_frame=true, fix_current_buffer=true, 
    prevent_redisplay=false) at ../../src/keyboard.c:9147
#8  0x0000000000581d55 in command_loop_1 () at ../../src/keyboard.c:1368
#9  0x0000000000638529 in internal_condition_case (bfun=0x581909 <command_loop_1>, 
    handlers=XIL(0x5250), hfun=0x580f4c <cmd_error>) at ../../src/eval.c:1332
#10 0x0000000000581524 in command_loop_2 (ignore=XIL(0)) at ../../src/keyboard.c:1110
#11 0x0000000000637a32 in internal_catch (tag=XIL(0xc6f0), func=0x5814f7 <command_loop_2>, arg=XIL(0))
    at ../../src/eval.c:1097
#12 0x00000000005814c2 in command_loop () at ../../src/keyboard.c:1089
#13 0x0000000000580a36 in recursive_edit_1 () at ../../src/keyboard.c:695
#14 0x0000000000580c2b in Frecursive_edit () at ../../src/keyboard.c:766
#15 0x000000000057e7c6 in main (argc=1, argv=0x7fffffffea38) at ../../src/emacs.c:1713
(gdb) frame 3
#3  0x0000000000464716 in reconsider_clip_changes (w=0x60537f0) at ../../src/xdisp.c:13727
13727	  struct buffer *b = XBUFFER (w->contents);
(gdb) p w->contents
$1 = XIL(0)