vim-patch:partial:9.2.0806: 'showcmd' may show internal command keys

Problem:  The `showcmd` statusline item may show internal command keys when a
          `<Cmd>` or `<ScriptCmd>` mapping redraws the statusline, and may
          leave stale text behind when `%S` is rendered directly.
Solution: Do not add these internal mapping dispatch keys to the `showcmd`
          buffer, and keep the clear state in sync when `%S` renders it
          (Barrett Ruth)

closes: vim/vim#20769

bd730293dc

Co-authored-by: Barrett Ruth <br@barrettruth.com>

src/nvim/normal.c

@@ -1851,6 +1851,7 @@ void may_clear_cmdline(void)
 
 // Routines for displaying a partly typed command
 static char old_showcmd_buf[SHOWCMD_BUFLEN];    // For push_showcmd()
+static bool showcmd_is_clear = true;
 static bool showcmd_visual = false;
 
 void clear_showcmd(void)
@@ -2043,9 +2044,14 @@ void pop_showcmd(void)
   display_showcmd();
 }
 
-static void display_showcmd(void)
+void showcmd_update_clear_state(void)
 {
   showcmd_is_clear = (showcmd_buf[0] == NUL);
+}
+
+static void display_showcmd(void)
+{
+  showcmd_update_clear_state();
 
   if (*p_sloc == 's') {
     if (showcmd_is_clear) {

src/nvim/normal.h

@@ -16,6 +16,5 @@ enum {
 
 /// 'showcmd' buffer shared between normal.c and statusline.c
 EXTERN char showcmd_buf[SHOWCMD_BUFLEN];
-EXTERN bool showcmd_is_clear INIT( = true);
 
 #include "normal.h.generated.h"

src/nvim/statusline.c

@@ -427,7 +427,7 @@ static void win_redr_stl_expr(win_T *wp, bool draw_winbar, bool draw_ruler, bool
   }
 
   if (p_sc && find_option(p_sloc) == opt_idx) {
-    showcmd_is_clear = (showcmd_buf[0] == NUL);
+    showcmd_update_clear_state();
   }
 
   if (ui_event) {
@@ -821,7 +821,7 @@ void draw_tabline(void)
         grid_line_puts(Columns - sc_width - (tabcount > 1) * 2,
                        showcmd_buf, sc_width, attr_nosel);
       }
-      showcmd_is_clear = (showcmd_buf[0] == NUL);
+      showcmd_update_clear_state();
     }
 
     // Put an "X" for closing the current tab if there are several.

test/old/testdir/test_statusline.vim

@@ -667,6 +667,47 @@ func Test_statusline_showcmd()
   call StopVimInTerminal(buf)
 endfunc
 
+func Test_statusline_showcmd_redraw_tabline()
+  CheckRunVimInTerminal
+
+  let lines =<< trim END
+    set showcmd showcmdloc=tabline showtabline=2 tabline=%S timeoutlen=0
+    nnoremap g :redraw<CR>
+    nnoremap gc <Nop>
+  END
+  call writefile(lines, 'XTest_statusline_showcmd_redraw', 'D')
+
+  let buf = RunVimInTerminal('-S XTest_statusline_showcmd_redraw', #{rows: 6, cols: 40})
+  call term_sendkeys(buf, 'g')
+  call WaitForAssert({-> assert_match(':redraw', term_getline(buf, 6))})
+  call WaitForAssert({-> assert_notmatch('^:', term_getline(buf, 1))})
+  call StopVimInTerminal(buf)
+endfunc
+
+func Test_statusline_showcmd_cmd_mapping()
+  set showcmd
+  set statusline=AAA%SBBB
+  set showcmdloc=statusline
+  try
+    let g:showcmd_statusline = ''
+    nnoremap <F3> <Cmd>let g:showcmd_statusline = <SID>get_statusline()<CR>
+    call feedkeys("\<F3>", 'xt')
+    call assert_equal('AAABBB', trim(g:showcmd_statusline))
+    let g:showcmd_statusline = ''
+    nunmap <F3>
+
+    "nnoremap <F3> <ScriptCmd>let g:showcmd_statusline = <SID>get_statusline()<CR>
+    "call feedkeys("\<F3>", 'xt')
+    "call assert_equal('AAABBB', trim(g:showcmd_statusline))
+  finally
+    silent! nunmap <F3>
+    unlet! g:showcmd_statusline
+    set showcmd&
+    set statusline&
+    set showcmdloc&
+  endtry
+endfunc
+
 func Test_statusline_highlight_group_cleared()
   CheckScreendump