patch 9.0.0114: the command line takes up space even when not used

Problem:    The command line takes up space even when not used.
Solution:   Allow for 'cmdheight' to be set to zero. (Shougo Matsushita,
            closes #10675, closes #940)

runtime/doc/options.txt

@@ -1760,12 +1760,15 @@ A jump table for the options with a short description can be found at |Q_op|.
 
 						*'cmdheight'* *'ch'*
 'cmdheight' 'ch'	number	(default 1)
-			global
+			global or local to tab page
 	Number of screen lines to use for the command-line.  Helps avoiding
 	|hit-enter| prompts.
 	The value of this option is stored with the tab page, so that each tab
 	page can have a different value.
 
+	When 'cmdheight' is zero, there is no command-line unless it is being
+	used.  Any messages will cause the |hit-enter| prompt.
+
 						*'cmdwinheight'* *'cwh'*
 'cmdwinheight' 'cwh'	number	(default 7)
 			global
@@ -6446,9 +6449,11 @@ A jump table for the options with a short description can be found at |Q_op|.
 		45%	relative position in the file
 	If 'rulerformat' is set, it will determine the contents of the ruler.
 	Each window has its own ruler.  If a window has a status line, the
-	ruler is shown there.  Otherwise it is shown in the last line of the
+	ruler is shown there.  If a window doesn't have a status line and
-	screen.  If the statusline is given by 'statusline' (i.e. not empty),
+	'cmdheight' is zero, the ruler is not shown.  Otherwise it is shown in
-	this option takes precedence over 'ruler' and 'rulerformat'
+	the last line of the screen.  If the statusline is given by
+	'statusline' (i.e. not empty), this option takes precedence over
+	'ruler' and 'rulerformat'
 	If the number of characters displayed is different from the number of
 	bytes in the text (e.g., for a TAB or a multibyte character), both
 	the text column (byte number) and the screen column are shown,
@@ -7098,6 +7103,7 @@ A jump table for the options with a short description can be found at |Q_op|.
 			|+cmdline_info| feature}
 	Show (partial) command in the last line of the screen.  Set this
 	option off if your terminal is slow.
+	The option has no effect when 'cmdheight' is zero.
 	In Visual mode the size of the selected area is shown:
 	- When selecting characters within a line, the number of characters.
 	  If the number of bytes is different it is also displayed: "2-6"
@@ -7147,6 +7153,7 @@ A jump table for the options with a short description can be found at |Q_op|.
 	If in Insert, Replace or Visual mode put a message on the last line.
 	Use the 'M' flag in 'highlight' to set the type of highlighting for
 	this message.
+	The option has no effect when 'cmdheight' is zero.
 	When |XIM| may be used the message will include "XIM".  But this
 	doesn't mean XIM is really active, especially when 'imactivatekey' is
 	not set.

src/drawscreen.c

@@ -649,8 +649,8 @@ win_redr_ruler(win_T *wp, int always, int ignore_pum)
     int		off = 0;
     int		width;
 
-    // If 'ruler' off or redrawing disabled, don't do anything
+    // If 'ruler' off or messages area disabled, don't do anything
-    if (!p_ru)
+    if (!p_ru || (wp->w_status_height == 0 && p_ch == 0))
 	return;
 
     /*
@@ -671,7 +671,7 @@ win_redr_ruler(win_T *wp, int always, int ignore_pum)
 	return;
 
 #ifdef FEAT_STL_OPT
-    if (*p_ruf)
+    if (*p_ruf && p_ch > 0)
     {
 	int	called_emsg_before = called_emsg;
 
@@ -2506,7 +2506,8 @@ win_update(win_T *wp)
 	    // Past end of the window or end of the screen. Note that after
 	    // resizing wp->w_height may be end up too big. That's a problem
 	    // elsewhere, but prevent a crash here.
-	    if (row > wp->w_height || row + wp->w_winrow >= Rows)
+	    if (row > wp->w_height
+		    || row + wp->w_winrow >= (p_ch > 0 ? Rows : Rows + 1))
 	    {
 		// we may need the size of that too long line later on
 		if (dollar_vcol == -1)
@@ -2560,7 +2561,7 @@ win_update(win_T *wp)
 
 	// Safety check: if any of the wl_size values is wrong we might go over
 	// the end of w_lines[].
-	if (idx >= Rows)
+	if (idx >= (p_ch > 0 ? Rows : Rows + 1))
 	    break;
     }
 
@@ -2946,8 +2947,10 @@ redraw_asap(int type)
     schar_T	*screenline2 = NULL;	// copy from ScreenLines2[]
 
     redraw_later(type);
-    if (msg_scrolled || (State != MODE_NORMAL && State != MODE_NORMAL_BUSY)
+    if (msg_scrolled
-								    || exiting)
+	    || (State != MODE_NORMAL && State != MODE_NORMAL_BUSY)
+	    || exiting
+	    || p_ch == 0)
 	return ret;
 
     // Allocate space to save the text displayed in the command line area.

src/ex_cmds.c

@@ -3704,6 +3704,7 @@ ex_substitute(exarg_T *eap)
     int		endcolumn = FALSE;	// cursor in last column when done
     pos_T	old_cursor = curwin->w_cursor;
     int		start_nsubs;
+    int		cmdheight0 = p_ch == 0;
 #ifdef FEAT_EVAL
     int		save_ma = 0;
     int		save_sandbox = 0;
@@ -4010,6 +4011,14 @@ ex_substitute(exarg_T *eap)
 	}
     }
 
+    if (cmdheight0)
+    {
+	// If cmdheight is 0, cmdheight must be set to 1 when we enter command
+	// line.
+	set_option_value((char_u *)"ch", 1L, NULL, 0);
+	redraw_statuslines();
+    }
+
     /*
      * Check for a match on each line.
      */
@@ -4833,6 +4842,10 @@ outofmem:
 	changed_window_setting();
 #endif
 
+    // Restore cmdheight
+    if (cmdheight0)
+	set_option_value((char_u *)"ch", 0L, NULL, 0);
+
     vim_regfree(regmatch.regprog);
     vim_free(sub_copy);
 

src/ex_getln.c

@@ -1611,6 +1611,15 @@ getcmdline_int(
     int		did_save_ccline = FALSE;
     int		cmdline_type;
     int		wild_type;
+    int		cmdheight0 = p_ch == 0;
+
+    if (cmdheight0)
+    {
+	// If cmdheight is 0, cmdheight must be set to 1 when we enter command
+	// line.
+	set_option_value((char_u *)"ch", 1L, NULL, 0);
+	update_screen(VALID);                 // redraw the screen NOW
+    }
 
     // one recursion level deeper
     ++depth;
@@ -2595,6 +2604,13 @@ theend:
     {
 	char_u *p = ccline.cmdbuff;
 
+	if (cmdheight0)
+	{
+	    set_option_value((char_u *)"ch", 0L, NULL, 0);
+	    // Redraw is needed for command line completion
+	    redraw_all_later(CLEAR);
+	}
+
 	--depth;
 	if (did_save_ccline)
 	    restore_cmdline(&save_ccline);

src/getchar.c

@@ -2096,6 +2096,10 @@ getchar_common(typval_T *argvars, typval_T *rettv)
     --no_mapping;
     --allow_keys;
 
+    // redraw the screen after getchar()
+    if (p_ch == 0)
+	update_screen(CLEAR);
+
     set_vim_var_nr(VV_MOUSE_WIN, 0);
     set_vim_var_nr(VV_MOUSE_WINID, 0);
     set_vim_var_nr(VV_MOUSE_LNUM, 0);

src/message.c

@@ -953,7 +953,7 @@ msg_may_trunc(int force, char_u *s)
     // just in case.
     room = (int)(Rows - cmdline_row - 1) * Columns + sc_col - 1;
     if (room > 0 && (force || (shortmess(SHM_TRUNC) && !exmode_active))
-	    && (n = (int)STRLEN(s) - room) > 0)
+	    && (n = (int)STRLEN(s) - room) > 0 && p_ch > 0)
     {
 	if (has_mbyte)
 	{
@@ -1430,7 +1430,7 @@ msg_start(void)
     }
 
 #ifdef FEAT_EVAL
-    if (need_clr_eos)
+    if (need_clr_eos || p_ch == 0)
     {
 	// Halfway an ":echo" command and getting an (error) message: clear
 	// any text from the command.
@@ -1448,7 +1448,7 @@ msg_start(void)
 #endif
 	    0;
     }
-    else if (msg_didout)		    // start message on next line
+    else if (msg_didout || p_ch == 0)	    // start message on next line
     {
 	msg_putchar('\n');
 	did_return = TRUE;
@@ -3460,7 +3460,7 @@ msg_clr_eos_force(void)
 		out_str(T_CE);	// clear to end of line
 	}
     }
-    else
+    else if (p_ch > 0)
     {
 #ifdef FEAT_RIGHTLEFT
 	if (cmdmsg_rl)

src/normal.c

@@ -1798,6 +1798,9 @@ display_showcmd(void)
 {
     int	    len;
 
+    if (p_ch == 0)
+	return;
+
     cursor_off();
 
     len = (int)STRLEN(showcmd_buf);

src/ops.c

@@ -3260,6 +3260,11 @@ cursor_pos_info(dict_T *dict)
 	    // Don't shorten this message, the user asked for it.
 	    p = p_shm;
 	    p_shm = (char_u *)"";
+	    if (p_ch < 1)
+	    {
+		msg_start();
+		msg_scroll = TRUE;
+	    }
 	    msg((char *)IObuff);
 	    p_shm = p;
 	}

src/option.c

@@ -3559,7 +3559,7 @@ set_num_option(
     // if p_ch changed value, change the command line height
     else if (pp == &p_ch)
     {
-	if (p_ch < 1)
+	if (p_ch < 0)
 	{
 	    errmsg = e_argument_must_be_positive;
 	    p_ch = 1;

src/register.c

@@ -371,6 +371,7 @@ do_record(int c)
 {
     char_u	    *p;
     static int	    regname;
+    static int	    changed_cmdheight = FALSE;
     yankreg_T	    *old_y_previous, *old_y_current;
     int		    retval;
 
@@ -385,6 +386,15 @@ do_record(int c)
 	    showmode();
 	    regname = c;
 	    retval = OK;
+
+	    if (p_ch < 1)
+	    {
+		// Enable macro indicator temporary
+		set_option_value((char_u *)"ch", 1L, NULL, 0);
+		update_screen(VALID);
+
+		changed_cmdheight = TRUE;
+	    }
 	}
     }
     else			    // stop recording
@@ -412,6 +422,13 @@ do_record(int c)
 	    y_previous = old_y_previous;
 	    y_current = old_y_current;
 	}
+
+	if (changed_cmdheight)
+	{
+	    // Restore cmdheight
+	    set_option_value((char_u *)"ch", 0L, NULL, 0);
+	    redraw_all_later(CLEAR);
+	}
     }
     return retval;
 }

src/screen.c

@@ -4726,7 +4726,7 @@ redrawing(void)
     int
 messaging(void)
 {
-    return (!(p_lz && char_avail() && !KeyTyped));
+    return (!(p_lz && char_avail() && !KeyTyped)) && p_ch > 0;
 }
 
 /*

src/testdir/gen_opt_test.vim

@@ -27,7 +27,7 @@ let fontname = has('win32') ? 'fixedsys' : 'fixed'
 " Two lists with values: values that work and values that fail.
 " When not listed, "othernum" or "otherstring" is used.
 let test_values = {
-      \ 'cmdheight': [[1, 2, 10], [-1, 0]],
+      \ 'cmdheight': [[0, 1, 2, 10], [-1]],
       \ 'cmdwinheight': [[1, 2, 10], [-1, 0]],
       \ 'columns': [[12, 80], [-1, 0, 10]],
       \ 'conceallevel': [[0, 1, 2, 3], [-1, 4, 99]],

src/testdir/test_messages.vim

@@ -387,4 +387,51 @@ func Test_fileinfo_after_echo()
   call delete('b.txt')
 endfunc
 
+func Test_cmdheight_zero()
+  set cmdheight=0
+  set showcmd
+  redraw!
+
+  echo 'test echo'
+  call assert_equal(116, screenchar(&lines, 1))
+  redraw!
+
+  echomsg 'test echomsg'
+  call assert_equal(116, screenchar(&lines, 1))
+  redraw!
+
+  call feedkeys(":ls\<CR>", "xt")
+  call assert_equal(':ls', Screenline(&lines - 1))
+  redraw!
+
+  let char = getchar(0)
+  call assert_match(char, 0)
+
+  " Check change/restore cmdheight when macro
+  call feedkeys("qa", "xt")
+  call assert_equal(&cmdheight, 1)
+  call feedkeys("q", "xt")
+  call assert_equal(&cmdheight, 0)
+
+  call setline(1, 'somestring')
+  call feedkeys("y", "n")
+  %s/somestring/otherstring/gc
+  call assert_equal(getline(1), 'otherstring')
+
+  call feedkeys("g\<C-g>", "xt")
+  call assert_match(
+        \ 'Col 1 of 11; Line 1 of 1; Word 1 of 1',
+        \ Screenline(&lines))
+
+  " Check split behavior
+  for i in range(1, 10)
+    split
+  endfor
+  only
+  call assert_equal(&cmdheight, 0)
+
+  set cmdheight&
+  set showcmd&
+endfunc
+
 " vim: shiftwidth=2 sts=2 expandtab

src/testdir/test_window_cmd.vim

@@ -1481,9 +1481,12 @@ func Test_win_move_statusline()
     call assert_equal(h0, winheight(0))
     call assert_equal(1, &cmdheight)
   endfor
+  " supports cmdheight=0
+  set cmdheight=0
   call assert_true(win_move_statusline(0, 1))
-  call assert_equal(h0, winheight(0))
+  call assert_equal(h0 + 1, winheight(0))
-  call assert_equal(1, &cmdheight)
+  call assert_equal(0, &cmdheight)
+  set cmdheight&
   " check win_move_statusline from bottom window on top window ID
   let id = win_getid(1)
   for offset in range(5)

src/version.c

@@ -735,6 +735,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    114,
 /**/
     113,
 /**/

src/window.c

@@ -1005,6 +1005,8 @@ win_split_ins(
 	needed = wmh1 + STATUS_HEIGHT;
 	if (flags & WSP_ROOM)
 	    needed += p_wh - wmh1;
+	if (p_ch == 0)
+	    needed += 1;  // Adjust for cmdheight=0.
 	if (flags & (WSP_BOT | WSP_TOP))
 	{
 	    minheight = frame_minheight(topframe, NOWIN) + need_status;
@@ -5668,6 +5670,8 @@ win_setheight_win(int height, win_T *win)
     if (full_screen && msg_scrolled == 0 && row < cmdline_row)
 	screen_fill(row, cmdline_row, 0, (int)Columns, ' ', ' ', 0);
     cmdline_row = row;
+    p_ch = MAX(Rows - cmdline_row, 0);
+    curtab->tp_ch_used = p_ch;
     msg_row = row;
     msg_col = 0;
 
@@ -5704,9 +5708,12 @@ frame_setheight(frame_T *curfrp, int height)
 
     if (curfrp->fr_parent == NULL)
     {
-	// topframe: can only change the command line
 	if (height > ROWS_AVAIL)
-	    height = ROWS_AVAIL;
+	    // If height is greater than the available space, try to create
+	    // space for the frame by reducing 'cmdheight' if possible, while
+	    // making sure `cmdheight` doesn't go below 1.
+	    height = MIN((p_ch > 0 ? ROWS_AVAIL + (p_ch - 1)
+							: ROWS_AVAIL), height);
 	if (height > 0)
 	    frame_new_height(curfrp, height, FALSE, FALSE);
     }
@@ -6037,7 +6044,7 @@ win_setminheight(void)
     while (p_wmh > 0)
     {
 	room = Rows - p_ch;
-	needed = min_rows() - 1;  // 1 was added for the cmdline
+	needed = min_rows();
 	if (room >= needed)
 	    break;
 	--p_wmh;
@@ -6143,9 +6150,7 @@ win_drag_status_line(win_T *dragwin, int offset)
 	 * Only dragging the last status line can reduce p_ch.
 	 */
 	room = Rows - cmdline_row;
-	if (curfr->fr_next == NULL)
+	if (curfr->fr_next != NULL)
-	    room -= 1;
-	else
 	    room -= p_ch;
 	if (room < 0)
 	    room = 0;
@@ -6196,9 +6201,7 @@ win_drag_status_line(win_T *dragwin, int offset)
     row = win_comp_pos();
     screen_fill(row, cmdline_row, 0, (int)Columns, ' ', ' ', 0);
     cmdline_row = row;
-    p_ch = Rows - cmdline_row;
+    p_ch = MAX(Rows - cmdline_row, 0);
-    if (p_ch < 1)
-	p_ch = 1;
     curtab->tp_ch_used = p_ch;
     redraw_all_later(SOME_VALID);
     showmode();
@@ -6733,7 +6736,8 @@ min_rows(void)
 	    total = n;
     }
     total += tabline_height();
-    total += 1;		// count the room for the command line
+    if (p_ch > 0)
+	total += 1;		// count the room for the command line
     return total;
 }