diff crashes with linematch when line longer than 500 chars

[lewis6991]

Neovim version (nvim -v)

v0.9.0-dev-499+g49c240d3a

Vim (not Nvim) behaves the same?

NA

Operating system/version

macOS 12.6

Terminal name/version

kitty 0.26.5

$TERM environment variable

xterm-kitty

Installation

build from repo

How to reproduce the issue

describe('regressions', function()
  local screen

  it("doesn't crash with long lines", function()
    clear()
    feed(':set diffopt+=linematch:30<cr>')
    screen = Screen.new(100, 20)
    screen:attach()
    -- line must be greater than MATCH_CHAR_MAX_LEN
    helpers.curbufmeths.set_lines(0, -1, false, { string.rep('a', 500)..'hello' })
    helpers.exec 'vnew'
    helpers.curbufmeths.set_lines(0, -1, false, { string.rep('a', 510)..'world' })
    helpers.exec 'windo diffthis'
  end)
end)

Expected behavior

No crash

Actual behavior

Crash

Thread 0 Crashed::  Dispatch queue: com.apple.main-thread
0   libsystem_kernel.dylib        	       0x18907ad98 __pthread_kill + 8
1   libsystem_pthread.dylib       	       0x1890afee0 pthread_kill + 288
2   libsystem_c.dylib             	       0x188fea3cc __abort + 128
3   libsystem_c.dylib             	       0x188fdbd48 __stack_chk_fail + 96
4   nvim                          	       0x104b5715c matching_chars + 712 (linematch.c:128)
5   nvim                          	       0x104b56b70 count_n_matched_chars + 232 (linematch.c:147)
6   nvim                          	       0x104b56884 try_possible_paths + 404 (linematch.c:204)
7   nvim                          	       0x104b569f8 try_possible_paths + 776 (linematch.c:224)
8   nvim                          	       0x104b569f8 try_possible_paths + 776 (linematch.c:224)
9   nvim                          	       0x104b5652c populate_tensor + 320 (linematch.c:279)
10  nvim                          	       0x104b5658c populate_tensor + 416 (linematch.c:286)
11  nvim                          	       0x104b5658c populate_tensor + 416 (linematch.c:286)
12  nvim                          	       0x104b562bc linematch_nbuffers + 468 (linematch.c:368)
13  nvim                          	       0x104a35cd8 run_linematch_algorithm + 348 (diff.c:2082)
14  nvim                          	       0x104a35928 diff_check_with_linestatus + 456 (diff.c:2151)
15  nvim                          	       0x104a33ba8 diff_check + 36 (diff.c:2219)
16  nvim                          	       0x104a32dd4 diff_redraw + 296 (diff.c:693)
17  nvim                          	       0x104a34398 ex_diffupdate + 536 (diff.c:998)
18  nvim                          	       0x104a357a8 diff_check_with_linestatus + 72 (diff.c:2113)
19  nvim                          	       0x104a33ba8 diff_check + 36 (diff.c:2219)
20  nvim                          	       0x104a32dd4 diff_redraw + 296 (diff.c:693)
21  nvim                          	       0x104a33014 diff_buf_add + 152 (diff.c:201)
22  nvim                          	       0x104a32c6c diff_buf_adjust + 328 (diff.c:177)
23  nvim                          	       0x104c07e28 set_bool_option + 2404 (option.c:2126)
24  nvim                          	       0x104c0eb18 set_option_value + 820 (option.c:3090)
25  nvim                          	       0x104c03bf4 set_option_value_give_err + 48 (option.c:3101)
26  nvim                          	       0x104a3527c set_diff_option + 112 (diff.c:1393)
27  nvim                          	       0x104a34fb8 diff_win_options + 752 (diff.c:1462)
28  nvim                          	       0x104b6dd1c main + 2924 (main.c:527)
29  dyld                          	       0x10549d08c start + 520