patch 9.0.0500: when quitting cmdline window with CTRL-C it remains visible

Problem:    When quitting the cmdline window with CTRL-C it remains visible.
Solution:   Redraw to avoid confusion. Adjust the error message.
            (closes #11152)  Adjust the cursor position after CTRL-C.

src/errors.h

@@ -17,7 +17,7 @@ EXTERN char e_backslash_should_be_followed_by[]
 	INIT(= N_("E10: \\ should be followed by /, ? or &"));
 #ifdef FEAT_CMDWIN
 EXTERN char e_invalid_in_cmdline_window[]
-	INIT(= N_("E11: Invalid in command-line window; <CR> executes, CTRL-C quits"));
+	INIT(= N_("E11: Invalid in command-line window; :q<CR> closes the window"));
 #endif
 EXTERN char e_command_not_allowed_from_vimrc_in_current_dir_or_tag_search[]
 	INIT(= N_("E12: Command not allowed from exrc/vimrc in current dir or tag search"));

src/ex_getln.c

@@ -4631,13 +4631,11 @@ open_cmdwin(void)
 	    ccline.cmdlen = (int)STRLEN(ccline.cmdbuff);
 	    ccline.cmdbufflen = ccline.cmdlen + 1;
 	    ccline.cmdpos = curwin->w_cursor.col;
-	    if (ccline.cmdpos > ccline.cmdlen)
+	    // If the cursor is on the last character, it probably should be
+	    // after it.
+	    if (ccline.cmdpos == ccline.cmdlen - 1
+		    || ccline.cmdpos > ccline.cmdlen)
 		ccline.cmdpos = ccline.cmdlen;
-	    if (cmdwin_result == K_IGNORE)
-	    {
-		set_cmdspos_cursor();
-		redrawcmd();
-	    }
 	}
 
 # ifdef FEAT_CONCEAL
@@ -4664,6 +4662,15 @@ open_cmdwin(void)
 	// Restore window sizes.
 	win_size_restore(&winsizes);
 	skip_win_fix_cursor = FALSE;
+
+	if (cmdwin_result == K_IGNORE)
+	{
+	    // It can be confusing that the cmdwin still shows, redraw the
+	    // screen.
+	    update_screen(UPD_VALID);
+	    set_cmdspos_cursor();
+	    redrawcmd();
+	}
     }
 
     ga_clear(&winsizes);

src/testdir/dumps/Test_cmdwin_wrong_command_1.dump

@@ -0,0 +1,12 @@
+| +0&#ffffff0@74
+|~+0#4040ff13&| @73
+|[+1#0000000&|N|o| |N|a|m|e|]| @47|0|,|0|-|1| @9|A|l@1
+|:+0#4040ff13&|l+0#af5f00255&>s| +0#0000000&@71
+|~+0#4040ff13&| @73
+|~| @73
+|~| @73
+|~| @73
+|~| @73
+|~| @73
+|[+3#0000000&|C|o|m@1|a|n|d| |L|i|n|e|]| @42|1|,|2| @11|A|l@1
+|E+0#ffffff16#e000002|1@1|:| |I|n|v|a|l|i|d| |i|n| |c|o|m@1|a|n|d|-|l|i|n|e| |w|i|n|d|o|w|;| |:|q|<|C|R|>| |c|l|o|s|e|s| |t|h|e| |w|i|n|d|o|w| +0#0000000#ffffff0@13

src/testdir/dumps/Test_cmdwin_wrong_command_2.dump

@@ -0,0 +1,12 @@
+| +0&#ffffff0@74
+|~+0#4040ff13&| @73
+|~| @73
+|~| @73
+|~| @73
+|~| @73
+|~| @73
+|~| @73
+|~| @73
+|~| @73
+|~| @73
+|:+0#0000000&|l|s> @71

src/testdir/test_cmdwin.vim

@@ -73,7 +73,6 @@ func Test_cmdwin_restore()
   call writefile(lines, 'XTest_restore', 'D')
 
   let buf = RunVimInTerminal('-S XTest_restore', {'rows': 12})
-  call TermWait(buf, 50)
   call term_sendkeys(buf, "q:")
   call VerifyScreenDump(buf, 'Test_cmdwin_restore_1', {})
 
@@ -93,11 +92,9 @@ func Test_cmdwin_restore()
 endfunc
 
 func Test_cmdwin_no_terminal()
-  CheckFeature terminal
+  CheckScreendump
-  CheckNotMSWindows
 
   let buf = RunVimInTerminal('', {'rows': 12})
-  call TermWait(buf, 50)
   call term_sendkeys(buf, ":set cmdheight=2\<CR>")
   call term_sendkeys(buf, "q:")
   call term_sendkeys(buf, ":let buf = term_start(['/bin/echo'], #{hidden: 1})\<CR>")
@@ -106,6 +103,22 @@ func Test_cmdwin_no_terminal()
   call StopVimInTerminal(buf)
 endfunc
 
+func Test_cmdwin_wrong_command()
+  CheckScreendump
+
+  let buf = RunVimInTerminal('', {'rows': 12})
+  call term_sendkeys(buf, "q:")
+  call term_sendkeys(buf, "als\<Esc>")
+  call term_sendkeys(buf, "\<C-W>k")
+  call VerifyScreenDump(buf, 'Test_cmdwin_wrong_command_1', {})
+
+  call term_sendkeys(buf, "\<C-C>")
+  call VerifyScreenDump(buf, 'Test_cmdwin_wrong_command_2', {})
+
+  call term_sendkeys(buf, ":q\<CR>")
+  call StopVimInTerminal(buf)
+endfunc
+
 func Test_cmdwin_feedkeys()
   " This should not generate E488
   call feedkeys("q:\<CR>", 'x')

src/version.c

@@ -699,6 +699,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    500,
 /**/
     499,
 /**/