win_line: Fix crash with 'rightleft' in :terminal #11460

fixes #11438 Backtrace: 0 schar_from_ascii ( p=0x801cc9e112c3 <error: Cannot access memory at address 0x801cc9e112c3>, c=32 ' ') at ../src/nvim/screen.c:5263 1 0x00007f31460eccc5 in win_line (wp=wp@entry=0x7fffc9df6230, lnum=lnum@entry=11, startrow=startrow@entry=10, endrow=41, nochange=false, number_only=number_only@entry=false) at ../src/nvim/screen.c:4025 2 0x00007f31460eed8e in win_update (wp=wp@entry=0x7fffc9df6230) at ../src/nvim/screen.c:1403 3 0x00007f31460f011f in update_screen (type=<optimized out>) at ../src/nvim/screen.c:502 4 0x00007f3146138ef4 in normal_redraw (s=s@entry=0x7fffd0a5f700) at ../src/nvim/normal.c:1247 5 0x00007f314613b159 in normal_check (state=0x7fffd0a5f700) at ../src/nvim/normal.c:1324 6 0x00007f31460accfe in state_enter (s=0x7fffd0a5f700) at ../src/nvim/state.c:28 7 0x00007f3146143099 in normal_enter (cmdwin=<optimized out>, noexmode=<optimized out>) at ../src/nvim/normal.c:463 8 0x00007f314618b541 in main (argc=<optimized out>, argv=<optimized out>) at ../src/nvim/main.c:580 (cherry picked from commit 1bb7ea1)
neovim · Nov 29, 2019 · 972dd75 · 972dd75
1 parent d379db4
commit 972dd75
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Showing 2 changed files with 23 additions and 3 deletions.
diff --git a/src/nvim/screen.c b/src/nvim/screen.c
@@ -4018,10 +4018,13 @@ win_line (
       if (wp->w_buffer->terminal) {
         // terminal buffers may need to highlight beyond the end of the
         // logical line
-        while (col < grid->Columns) {
+        int n = wp->w_p_rl ? -1 : 1;
+        while (col >= 0 && col < grid->Columns) {
           schar_from_ascii(linebuf_char[off], ' ');
-          linebuf_attr[off++] = term_attrs[vcol++];
-          col++;
+          linebuf_attr[off] = term_attrs[vcol];
+          off += n;
+          vcol += n;
+          col += n;
         }
       }
       grid_put_linebuf(grid, row, 0, col, grid->Columns, wp->w_p_rl, wp,

diff --git a/test/functional/terminal/buffer_spec.lua b/test/functional/terminal/buffer_spec.lua
@@ -5,6 +5,7 @@ local wait = helpers.wait
 local eval, feed_command, source = helpers.eval, helpers.feed_command, helpers.source
 local eq, neq = helpers.eq, helpers.neq
 local write_file = helpers.write_file
+local command= helpers.command
 
 describe(':terminal buffer', function()
   local screen
@@ -224,6 +225,22 @@ describe(':terminal buffer', function()
       neq('terminal', eval('&buftype'))
     end)
   end)
+
+  it('it works with set rightleft #11438', function()
+    local columns = eval('&columns')
+    feed(string.rep('a', columns))
+    command('set rightleft')
+    screen:expect([[
+                                               ydaer ytt|
+      {1:a}aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa|
+                                                        |
+                                                        |
+                                                        |
+                                                        |
+      {3:-- TERMINAL --}                                    |
+    ]])
+    command('bdelete!')
+  end)
 end)
 
 describe('No heap-buffer-overflow when using', function()