patch 9.1.0054: 'linebreak' may still apply to leading whitespace

Problem:  'linebreak' may still apply to leading whitespace
          (VanaIgr)
Solution: Compare pointers instead of virtual columns.
          (zeertzjq)

related: neovim/neovim#27180
closes: #13915

Co-authored-by: VanaIgr <vanaigranov@gmail.com>
Signed-off-by: zeertzjq <zeertzjq@outlook.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>

Author: 2 people

src/charset.c

@@ -1126,7 +1126,6 @@ win_lbr_chartabsize(
     int		n;
     char_u	*sbr;
     int		no_sbr = FALSE;
-    colnr_T	vcol_start = 0; // start from where to consider linebreak
 #endif
 
 #if defined(FEAT_PROP_POPUP)
@@ -1352,22 +1351,21 @@ win_lbr_chartabsize(
     if (headp != NULL)
 	*headp = head;
 
+    int need_lbr = FALSE;
     /*
      * If 'linebreak' set check at a blank before a non-blank if the line
-     * needs a break here
+     * needs a break here.
      */
-    if (wp->w_p_lbr && wp->w_p_wrap && wp->w_width != 0)
+    if (wp->w_p_lbr && wp->w_p_wrap && wp->w_width != 0
+	    && VIM_ISBREAK((int)s[0]) && !VIM_ISBREAK((int)s[1]))
     {
 	char_u	*t = cts->cts_line;
 	while (VIM_ISBREAK((int)t[0]))
 	    t++;
-	vcol_start = t - cts->cts_line;
+	// 'linebreak' is only needed when not in leading whitespace.
+	need_lbr = s >= t;
     }
-    if (wp->w_p_lbr && vcol_start <= vcol
-	    && VIM_ISBREAK((int)s[0])
-	    && !VIM_ISBREAK((int)s[1])
-	    && wp->w_p_wrap
-	    && wp->w_width != 0)
+    if (need_lbr)
     {
 	/*
 	 * Count all characters from first non-blank after a blank up to next

src/testdir/test_listlbr.vim

@@ -374,13 +374,13 @@ endfunc
 
 func Test_linebreak_no_break_after_whitespace_only()
   call s:test_windows('setl ts=4 linebreak wrap')
-  call setline(1, "\tabcdefghijklmnopqrstuvwxyz" ..
+  call setline(1, "\t  abcdefghijklmnopqrstuvwxyz" ..
         \ "abcdefghijklmnopqrstuvwxyz")
   let lines = s:screen_lines([1, 4], winwidth(0))
   let expect = [
-\ "    abcdefghijklmnop",
-\ "qrstuvwxyzabcdefghij",
-\ "klmnopqrstuvwxyz    ",
+\ "      abcdefghijklmn",
+\ "opqrstuvwxyzabcdefgh",
+\ "ijklmnopqrstuvwxyz  ",
 \ "~                   ",
 \ ]
   call s:compare_lines(expect, lines)

src/version.c

@@ -704,6 +704,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    54,
 /**/
     53,
 /**/