vim-patch:8.1.1078: when 'listchars' is set a composing char on a space is wrong

Problem:    When 'listchars' is set a composing char on a space is wrong.
Solution:   Separate handling a non-breaking space and a space. (Yasuhiro
            Matsumoto, closes vim/vim#4046)
https://github.com/vim/vim/commit/5f8069bbf5d989936a2f4d7a76ae42434017e3a2

2 files changed, 45 insertions, 18 deletions

diff --git a/src/nvim/screen.c b/src/nvim/screen.c
index e1846d4569..5ce8e0b348 100644
--- a/src/nvim/screen.c
+++ b/src/nvim/screen.c
@@ -3581,24 +3581,28 @@ static int win_line(win_T *wp, linenr_T lnum, int startrow, int endrow, bool noc
         }
 
         // 'list': change char 160 to 'nbsp' and space to 'space'.
-        if (wp->w_p_list
-            && (((c == 160
-                  || (mb_utf8 && (mb_c == 160 || mb_c == 0x202f)))
-                 && curwin->w_p_lcs_chars.nbsp)
-                || (c == ' ' && curwin->w_p_lcs_chars.space
-                    && ptr - line >= leadcol
-                    && ptr - line <= trailcol))) {
-          c = (c == ' ') ? wp->w_p_lcs_chars.space : wp->w_p_lcs_chars.nbsp;
-          n_attr = 1;
-          extra_attr = win_hl_attr(wp, HLF_0);
-          saved_attr2 = char_attr;  // save current attr
-          mb_c = c;
-          if (utf_char2len(c) > 1) {
-            mb_utf8 = true;
-            u8cc[0] = 0;
-            c = 0xc0;
-          } else {
-            mb_utf8 = false;
+        if (wp->w_p_list) {
+          if ((c == 160 || (mb_utf8 && (mb_c == 160 || mb_c == 0x202f)))
+              && wp->w_p_lcs_chars.nbsp) {
+            c = wp->w_p_lcs_chars.nbsp;
+            mb_c = c;
+            if (utf_char2len(c) > 1) {
+              mb_utf8 = true;
+              u8cc[0] = 0;
+              c = 0xc0;
+            } else {
+              mb_utf8 = false;
+            }
+          } else if (c == ' '
+                     && wp->w_p_lcs_chars.space
+                     && ptr - line >= leadcol
+                     && ptr - line <= trailcol) {
+            c = wp->w_p_lcs_chars.space;
+            if (mb_utf8 == false) {
+              n_attr = 1;
+              extra_attr = win_hl_attr(wp, HLF_0);
+              saved_attr2 = char_attr;  // save current attr
+            }
           }
         }
 
diff --git a/src/nvim/testdir/test_listchars.vim b/src/nvim/testdir/test_listchars.vim
index 4cb609aaf0..191e2afdf1 100644
--- a/src/nvim/testdir/test_listchars.vim
+++ b/src/nvim/testdir/test_listchars.vim
@@ -181,3 +181,26 @@ func Test_listchars()
   enew!
   set listchars& ff&
 endfunc
+
+func Test_listchars_composing()
+  enew!
+  let oldencoding=&encoding
+  set encoding=utf-8
+  set ff=unix
+  set list
+
+  set listchars=eol:$,space:_
+  call append(0, [
+        \ "  \u3099	 \u309A"
+        \ ])
+  let expected = [
+        \ "_ \u3099^I \u309A$"
+        \ ]
+  redraw!
+  call cursor(1, 1)
+  let got = ScreenLinesUtf8(1, virtcol('$'))
+  bw!
+  call assert_equal(expected, got)
+  let &encoding=oldencoding
+  set listchars& ff&
+endfunction