vim-patch:8.2.4093: cached breakindent values not initialized properly

Problem:    Cached breakindent values not initialized properly.
Solution:   Initialize and cache formatlistpat. (Christian Brabandt,
            closes vim/vim#9526, closes vim/vim#9512)
c53b467473

Co-authored-by: Christian Brabandt <cb@256bit.org>

runtime/doc/options.txt

@@ -1053,6 +1053,7 @@ A jump table for the options with a short description can be found at |Q_op|.
 			    text should normally be narrower. This prevents
 			    text indented almost to the right window border
 			    occupying lot of vertical space when broken.
+			    (default: 20)
 		shift:{n}   After applying 'breakindent', the wrapped line's
 			    beginning will be shifted by the given number of
 			    characters.  It permits dynamic French paragraph

src/nvim/indent.c

@@ -789,16 +789,22 @@ int get_breakindent_win(win_T *wp, char_u *line)
   static long *prev_vts = NULL;  // Cached vartabs values.
   static int prev_list = 0;  // cached list value
   static int prev_listopt = 0;  // cached w_p_briopt_list value
+  static char *prev_flp = NULL;  // cached formatlistpat value
   int bri = 0;
   // window width minus window margin space, i.e. what rests for text
   const int eff_wwidth = wp->w_width_inner -
                          ((wp->w_p_nu || wp->w_p_rnu)
                           && (vim_strchr(p_cpo, CPO_NUMCOL) == NULL) ? number_width(wp) + 1 : 0);
 
-  // used cached indent, unless line, 'tabstop' or briopt_list changed
+  // used cached indent, unless
+  // - line pointer changed
+  // - 'tabstop' changed
+  // - 'briopt_list changed' changed or
+  // - 'formatlistpattern' changed
   if (prev_line != line || prev_ts != wp->w_buffer->b_p_ts
       || prev_tick != buf_get_changedtick(wp->w_buffer)
       || prev_listopt != wp->w_briopt_list
+      || (prev_flp == NULL || (strcmp(prev_flp, get_flp_value(wp->w_buffer)) != 0))
       || prev_vts != wp->w_buffer->b_p_vts_array) {
     prev_line = line;
     prev_ts = wp->w_buffer->b_p_ts;
@@ -809,11 +815,13 @@ int get_breakindent_win(win_T *wp, char_u *line)
                                       wp->w_buffer->b_p_vts_array,
                                       wp->w_p_list);
     prev_listopt = wp->w_briopt_list;
+    prev_list = 0;
+    xfree(prev_flp);
+    prev_flp = xstrdup(get_flp_value(wp->w_buffer));
     // add additional indent for numbered lists
     if (wp->w_briopt_list != 0) {
       regmatch_T regmatch = {
-        .regprog = vim_regcomp(curbuf->b_p_flp,
-                               RE_MAGIC + RE_STRING + RE_AUTO + RE_STRICT),
+        .regprog = vim_regcomp(prev_flp, RE_MAGIC + RE_STRING + RE_AUTO + RE_STRICT),
       };
       if (regmatch.regprog != NULL) {
         regmatch.rm_ic = false;

src/nvim/option.c

@@ -5220,6 +5220,18 @@ unsigned int get_bkc_value(buf_T *buf)
   return buf->b_bkc_flags ? buf->b_bkc_flags : bkc_flags;
 }
 
+/// Get the local or global value of 'formatlistpat'.
+///
+/// @param buf The buffer.
+char *get_flp_value(buf_T *buf)
+{
+  return buf->b_p_flp ? buf->b_p_flp : p_flp;
+  if (buf->b_p_flp == NULL || *buf->b_p_flp == NUL) {
+    return p_flp;
+  }
+  return buf->b_p_flp;
+}
+
 /// Get the local or global value of the 'virtualedit' flags.
 unsigned int get_ve_flags(void)
 {

src/nvim/testdir/test_breakindent.vim

@@ -889,4 +889,61 @@ func Test_window_resize_with_linebreak()
   %bw!
 endfunc
 
+func Test_no_spurious_match()
+  let s:input = printf('- y %s y %s', repeat('x', 50), repeat('x', 50))
+  call s:test_windows('setl breakindent breakindentopt=list:-1 formatlistpat=^- hls')
+  let @/ = '\%>3v[y]'
+  redraw!
+  call searchcount().total->assert_equal(1)
+  " cleanup
+  set hls&vim
+  let s:input = "\tabcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOP"
+  bwipeout!
+endfunc
+
+func Test_no_extra_indent()
+  call s:test_windows('setl breakindent breakindentopt=list:-1,min:10')
+  %d
+  let &l:formatlistpat='^\s*\d\+\.\s\+'
+  let text = 'word '
+  let len = text->strcharlen()
+  let line1 = text->repeat((winwidth(0) / len) * 2)
+  let line2 = repeat(' ', 2) .. '1. ' .. line1
+  call setline(1, [line2])
+  redraw!
+  " 1) matches formatlist pattern, so indent
+  let expect = [
+  \ "  1. word word word ",
+  \ "     word word word ",
+  \ "     word word      ",
+  \ "~                   ",
+  \ ]
+  let lines = s:screen_lines2(1, 4, 20)
+  call s:compare_lines(expect, lines)
+  " 2) change formatlist pattern
+  " -> indent adjusted
+  let &l:formatlistpat='^\s*\d\+\.'
+  let expect = [
+  \ "  1. word word word ",
+  \ "    word word word  ",
+  \ "    word word       ",
+  \ "~                   ",
+  \ ]
+  let lines = s:screen_lines2(1, 4, 20)
+  " 3) add something in front, no additional indent
+  norm! gg0
+  exe ":norm! 5iword \<esc>"
+  redraw!
+  let expect = [
+  \ "word word word word ",
+  \ "word   1. word word ",
+  \ "word word word word ",
+  \ "word word           ",
+  \ "~                   ",
+  \ ]
+  let lines = s:screen_lines2(1, 5, 20)
+  call s:compare_lines(expect, lines)
+  bwipeout!
+endfunc
+
 " vim: shiftwidth=2 sts=2 expandtab