patch 9.0.0340: the 'cmdheight' zero support causes too much trouble

Problem:    The 'cmdheight' zero support causes too much trouble.
Solution:   Revert support for 'cmdheight' being zero.

Author: brammool

runtime/doc/options.txt

@@ -1783,18 +1783,11 @@ A jump table for the options with a short description can be found at |Q_op|.
 						*'cmdheight'* *'ch'*
 'cmdheight' 'ch'	number	(default 1)
 			global or local to tab page
-	Number of screen lines to use for the command-line.  Helps avoiding
-	|hit-enter| prompts.
+	Number of screen lines to use for the command-line.  A larger value
+	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.  Informative messages will be displayed in a popup notification
-	window at the bottom if the window, using the MessageWindow highlight
-	group {only if compiled with the +popupwin and +timers features},
-	otherwise they will not be displayed.  Other messages will cause the
-	|hit-enter| prompt.  Expect some other unexpected behavior too.
-
 						*'cmdwinheight'* *'cwh'*
 'cmdwinheight' 'cwh'	number	(default 7)
 			global
@@ -6474,11 +6467,9 @@ 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.  If a window doesn't have a status line and
-	'cmdheight' is zero, the ruler is not shown.  Otherwise it is shown in
-	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'.
+	ruler is shown there.  Otherwise it is shown in 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,
@@ -7128,7 +7119,6 @@ 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"
@@ -7178,7 +7168,6 @@ 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

@@ -654,8 +654,8 @@ win_redr_ruler(win_T *wp, int always, int ignore_pum)
     int		off = 0;
     int		width;
 
-    // If 'ruler' off or messages area disabled, don't do anything
-    if (!p_ru || (wp->w_status_height == 0 && p_ch == 0))
+    // If 'ruler' off don't do anything
+    if (!p_ru)
 	return;
 
     /*
@@ -676,7 +676,7 @@ win_redr_ruler(win_T *wp, int always, int ignore_pum)
 	return;
 
 #ifdef FEAT_STL_OPT
-    if (*p_ruf && p_ch > 0)
+    if (*p_ruf)
     {
 	int	called_emsg_before = called_emsg;
 
@@ -1814,13 +1814,9 @@ win_update(win_T *wp)
 
 			    // Move the entries that were scrolled, disable
 			    // the entries for the lines to be redrawn.
-			    // Avoid using a wrong index when 'cmdheight' is
-			    // zero and wp->w_height == Rows.
 			    if ((wp->w_lines_valid += j) > wp->w_height)
 				wp->w_lines_valid = wp->w_height;
-			    for (idx = wp->w_lines_valid >= wp->w_height
-				    ? wp->w_height - 1 : wp->w_lines_valid;
-							   idx - j >= 0; idx--)
+			    for (idx = wp->w_lines_valid; idx - j >= 0; idx--)
 				wp->w_lines[idx] = wp->w_lines[idx - j];
 			    while (idx >= 0)
 				wp->w_lines[idx--].wl_valid = FALSE;
@@ -2420,8 +2416,7 @@ win_update(win_T *wp)
 			    if (wp->w_lines_valid > wp->w_height)
 				wp->w_lines_valid = wp->w_height;
 			    for (i = wp->w_lines_valid; i - j >= idx; --i)
-				if (i < Rows)
-				    wp->w_lines[i] = wp->w_lines[i - j];
+				wp->w_lines[i] = wp->w_lines[i - j];
 
 			    // The w_lines[] entries for inserted lines are
 			    // now invalid, but wl_size may be used above.
@@ -2502,8 +2497,7 @@ 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 >= (p_ch > 0 ? Rows : Rows + 1))
+	    if (row > wp->w_height || row + wp->w_winrow >= Rows)
 	    {
 		// we may need the size of that too long line later on
 		if (dollar_vcol == -1)
@@ -2557,7 +2551,7 @@ 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 >= (p_ch > 0 ? Rows : Rows + 1))
+	if (idx >= Rows)
 	    break;
     }
 
@@ -2945,8 +2939,7 @@ redraw_asap(int type)
     redraw_later(type);
     if (msg_scrolled
 	    || (State != MODE_NORMAL && State != MODE_NORMAL_BUSY)
-	    || exiting
-	    || p_ch == 0)
+	    || exiting)
 	return ret;
 
     // Allocate space to save the text displayed in the command line area.

src/eval.c

@@ -6832,17 +6832,18 @@ ex_execute(exarg_T *eap)
     if (eap->skip)
 	--emsg_skip;
 #ifdef HAS_MESSAGE_WINDOW
-    if (use_message_window() && eap->cmdidx != CMD_execute)
+    if (eap->cmdidx == CMD_echowindow)
     {
 	// show the message window now
 	ex_redraw(eap);
 
 	// do not overwrite messages
+	// TODO: only for message window
 	msg_didout = TRUE;
 	if (msg_col == 0)
 	    msg_col = 1;
+	in_echowindow = FALSE;
     }
-    in_echowindow = FALSE;
 #endif
     set_nextcmd(eap, arg);
 }

src/ex_cmds.c

@@ -1011,7 +1011,6 @@ do_bang(
     if (addr_count == 0)		// :!
     {
 	// echo the command
-	dont_use_message_window();
 	msg_start();
 	msg_putchar(':');
 	msg_putchar('!');
@@ -3702,7 +3701,6 @@ 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;
@@ -4012,14 +4010,6 @@ 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.
      */
@@ -4902,10 +4892,6 @@ ex_substitute(exarg_T *eap)
 	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_docmd.c

@@ -8370,14 +8370,9 @@ ex_redraw(exarg_T *eap)
     // After drawing the statusline screen_attr may still be set.
     screen_stop_highlight();
 
-#ifdef HAS_MESSAGE_WINDOW
-    if (!use_message_window())  // append messages in the message window
-#endif
-    {
-	// Reset msg_didout, so that a message that's there is overwritten.
-	msg_didout = FALSE;
-	msg_col = 0;
-    }
+    // Reset msg_didout, so that a message that's there is overwritten.
+    msg_didout = FALSE;
+    msg_col = 0;
 
     // No need to wait after an intentional redraw.
     need_wait_return = FALSE;

src/ex_getln.c

@@ -1591,25 +1591,6 @@ getcmdline_int(
     int		did_save_ccline = FALSE;
     int		cmdline_type;
     int		wild_type;
-    int		cmdheight0 = p_ch == 0;
-
-    if (cmdheight0)
-    {
-	int  save_so = lastwin->w_p_so;
-
-	// If cmdheight is 0, cmdheight must be set to 1 when we enter the
-	// command line.  Set "made_cmdheight_nonzero" and reset 'scrolloff' to
-	// avoid scrolling the last window.
-	made_cmdheight_nonzero = TRUE;
-	lastwin->w_p_so = 0;
-	set_option_value((char_u *)"ch", 1L, NULL, 0);
-#ifdef HAS_MESSAGE_WINDOW
-	popup_hide_message_win();
-#endif
-	update_screen(UPD_VALID);                 // redraw the screen NOW
-	made_cmdheight_nonzero = FALSE;
-	lastwin->w_p_so = save_so;
-    }
 
     // one recursion level deeper
     ++depth;
@@ -2577,15 +2558,6 @@ getcmdline_int(
     {
 	char_u *p = ccline.cmdbuff;
 
-	if (cmdheight0)
-	{
-	    made_cmdheight_nonzero = TRUE;
-	    set_option_value((char_u *)"ch", 0L, NULL, 0);
-	    // Redraw is needed for command line completion
-	    redraw_all_later(UPD_NOT_VALID);
-	    made_cmdheight_nonzero = FALSE;
-	}
-
 	--depth;
 	if (did_save_ccline)
 	    restore_cmdline(&save_ccline);

src/getchar.c

@@ -2096,10 +2096,6 @@ getchar_common(typval_T *argvars, typval_T *rettv)
     --no_mapping;
     --allow_keys;
 
-    // redraw the screen after getchar()
-    if (p_ch == 0)
-	update_screen(UPD_NOT_VALID);
-
     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/globals.h

@@ -1734,6 +1734,3 @@ EXTERN int channel_need_redraw INIT(= FALSE);
 // While executing a regexp and set to OPTION_MAGIC_ON or OPTION_MAGIC_OFF this
 // overrules p_magic.  Otherwise set to OPTION_MAGIC_NOT_SET.
 EXTERN optmagic_T magic_overruled INIT(= OPTION_MAGIC_NOT_SET);
-
-// Set when 'cmdheight' is changed from zero to one temporarily.
-EXTERN int made_cmdheight_nonzero INIT(= FALSE);

src/highlight.c

@@ -1429,7 +1429,6 @@ do_highlight(
     // If no argument, list current highlighting.
     if (!init && ends_excmd2(line - 1, line))
     {
-	dont_use_message_window();
 	for (i = 1; i <= highlight_ga.ga_len && !got_int; ++i)
 	    // TODO: only call when the group has attributes set
 	    highlight_list_one((int)i);

src/memline.c

@@ -4640,7 +4640,6 @@ attention_message(
     stat_T	st;
     time_t	swap_mtime;
 
-    dont_use_message_window();
     ++no_wait_return;
     (void)emsg(_(e_attention));
     msg_puts(_("\nFound a swap file by the name \""));