After changes for auto-composition aware string-width (*),
emacs segfaults frequently on startup under macOS.

gdb 'bt full’ is attached:
  emacs_crash-lisp_string_width-gdb_bt_full.txt
  emacs_crash-lisp_string_width-macOS_report.txt

On my machine, crash occurrence frequency can be increased with
attached init.el.  Unfortunately, I cannot reproduce the crash with
`--enable-checking='yes,glyphs' --enable-check-lisp-object-type`
configure options.

Sometimes emacs starts without crash, but font setting is corrupted
like the attached screenshot: after-lisp_string_width-autocmp.png

Regards,
—Naofumi

(*)
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commit 85da7b57bc204c4cc6953156c1a9a4dc6e875541
Author: Eli Zaretskii <eliz@gnu.org>
Date:   Wed May 26 20:08:47 2021 +0300

    Make 'string-width' auto-composition aware

    * src/composite.c (find_automatic_composition): Now extern.
    (char_composable_p): Don't assume 'unicode-category-table' is
    always available.
    * src/composite.h (find_automatic_composition): Add prototype.
    * src/character.c (lisp_string_width): Support automatic
    compositions; call 'find_automatic_composition' when
    'auto-composition-mode' is ON.
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(gdb) bt
#0  0x000000010028e955 in SYMBOL_NAME (sym=0x104621ba0) at ./lisp.h:2208
#1  0x000000010028e42d in font_style_to_value (prop=FONT_WIDTH_INDEX,
    val=0x104621ba0, noerror=true) at font.c:366
#2  0x00000001002976de in font_select_entity (f=0x10433f230,
    entities=0x1048cb913, attrs=0x103778800, pixel_size=12, c=-1)
    at font.c:3159
#3  0x00000001002971b9 in font_find_for_lface (f=0x10433f230,
    attrs=0x103778800, spec=0x10422c7ed, c=-1) at font.c:3302
#4  0x000000010033905e in fontset_find_font (fontset=0x104419835, c=1603,
    face=0x103778800, charset_id=-1, fallback=false) at fontset.c:660
#5  0x0000000100331c94 in fontset_font (fontset=0x10493a08d, c=1603,
    face=0x103778800, id=-1) at fontset.c:782
#6  0x000000010033228d in font_for_char (face=0x103778800, c=1603, pos=308,
    object=0x1033e79c4) at fontset.c:1063
#7  0x0000000100299d4f in font_range (pos=309, pos_byte=336,
    limit=0x7ffeefbf1310, w=0x104342e20, face=0x103778800, string=0x1033e79c4)
    at font.c:3883
#8  0x0000000100324fce in autocmp_chars (rule=0x105f2311d, charpos=308,
    bytepos=334, limit=312, win=0x104342e20, face=0x0, string=0x1033e79c4,
    direction=0x0) at composite.c:923
#9  0x0000000100325f1d in find_automatic_composition (pos=308, limit=308,
    start=0x7ffeefbf15a8, end=0x7ffeefbf15a0, gstring=0x7ffeefbf15b8,
    string=0x1033e79c4) at composite.c:1612
#10 0x00000001001248c8 in lisp_string_width (string=0x1033e79c4, from=0,
    to=479, precision=-1, nchars=0x7ffeefbf1a28, nbytes=0x7ffeefbf1a20)
    at character.c:375
#11 0x00000001002514db in styled_format (nargs=2, args=0x7ffeefbf74c0,
    message=false) at editfns.c:3392
#12 0x000000010024f48f in Fformat (nargs=2, args=0x7ffeefbf74c0)
    at editfns.c:3061
#13 0x000000010026b23b in call3 (fn=0x100420bf5, arg1=0x1000000000,
    arg2=0x7ffeefbf73f0, arg3=0x10026ec04 <xcdr_addr+20>) at eval.c:2912
#14 0x00000037c0001000 in ?? ()
#15 0x0000003700007170 in ?? ()
#16 0x00007fff80898338 in ?? ()
#17 0x0001003700000037 in ?? ()
#18 0x00007ffe0000005d in ?? ()
#19 0x00007ffeefbf751c in ?? ()
#20 0x0000000000007170 in ?? ()
#21 0x0000000000000000 in ?? ()
(gdb) 
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