patch 9.1.1123: popup hi groups not falling back to defaults

Problem:  Highlight groups PopupSelected/PopupNotification/
          MessageWindow are supposed to fall back to default highlight
          groups if they are not defined. However, once a colorscheme
          has defined them, switching to another colorscheme that
          doesn't do so will leave behind a cleared colorscheme, which
          causes the fallback to fail.

Solution: Set up default links to the relevant fallback highlight
          groups, which makes sure a `:hi clear` command will reset the
          state properly (Yee Cheng Chin).

closes: #16676

Signed-off-by: Yee Cheng Chin <ychin.git@gmail.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>

runtime/doc/popup.txt

@@ -1,4 +1,4 @@
-*popup.txt*  For Vim version 9.1.  Last change: 2025 Jan 08
+*popup.txt*  For Vim version 9.1.  Last change: 2025 Feb 20
 
 
 		  VIM REFERENCE MANUAL    by Bram Moolenaar
@@ -504,7 +504,7 @@ popup_menu({what}, {options})				 *popup_menu()*
 				\ mapping: 0,
 				\ })
 <		The current line is highlighted with a match using
-		"PopupSelected", or "PmenuSel" if that is not defined.
+		|hl-PopupSelected| which is linked to "PmenuSel" by default.
 
 		Use {options} to change the properties.  Should at least set
 		"callback" to a function that handles the selected item.
@@ -559,7 +559,7 @@ popup_notification({what}, {options})			 *popup_notification()*
 				\ close: 'click',
 				\ padding: [0,1,0,1],
 				\ })
-<		The PopupNotification highlight group is used instead of
+<		The |hl-PopupNotification| highlight group is used instead of
 		WarningMsg if it is defined.
 
 		Without the |+timers| feature the popup will not disappear

runtime/doc/syntax.txt

@@ -1,4 +1,4 @@
-*syntax.txt*	For Vim version 9.1.  Last change: 2025 Jan 20
+*syntax.txt*	For Vim version 9.1.  Last change: 2025 Feb 20
 
 
 		  VIM REFERENCE MANUAL	  by Bram Moolenaar
@@ -5831,8 +5831,8 @@ CursorLineSign	Like SignColumn when 'cursorline' is set for the cursor line.
 MatchParen	Character under the cursor or just before it, if it
 		is a paired bracket, and its match. |pi_paren.txt|
 							*hl-MessageWindow*
-MessageWindow	Messages popup window used by `:echowindow`.  If not defined
-		|hl-WarningMsg| is used.
+MessageWindow	Messages popup window used by `:echowindow`.  Linked to
+		|hl-WarningMsg| by default.
 							*hl-ModeMsg*
 ModeMsg		'showmode' message (e.g., "-- INSERT --").
 							*hl-MsgArea*
@@ -5872,10 +5872,13 @@ PmenuMatchSel	Popup menu: Matched text in selected item. Applied in
 		combination with |hl-PmenuSel|.
 							*hl-ComplMatchIns*
 ComplMatchIns	Matched text of the currently inserted completion.
+							*hl-PopupSelected*
+PopupSelected	Popup window created with |popup_menu()|.  Linked to
+		|hl-PmenuSel| by default.
 							*hl-PopupNotification*
 PopupNotification
-		Popup window created with |popup_notification()|.  If not
-		defined |hl-WarningMsg| is used.
+		Popup window created with |popup_notification()|.  Linked to
+		|hl-WarningMsg| by default.
 							*hl-Question*
 Question	|hit-enter| prompt and yes/no questions.
 							*hl-QuickFixLine*

runtime/doc/tags

@@ -8191,6 +8191,7 @@ hl-PmenuSbar	syntax.txt	/*hl-PmenuSbar*
 hl-PmenuSel	syntax.txt	/*hl-PmenuSel*
 hl-PmenuThumb	syntax.txt	/*hl-PmenuThumb*
 hl-PopupNotification	syntax.txt	/*hl-PopupNotification*
+hl-PopupSelected	syntax.txt	/*hl-PopupSelected*
 hl-Question	syntax.txt	/*hl-Question*
 hl-QuickFixLine	syntax.txt	/*hl-QuickFixLine*
 hl-Scrollbar	syntax.txt	/*hl-Scrollbar*

src/highlight.c

@@ -262,6 +262,9 @@ static char *(highlight_init_both[]) = {
     "default link PmenuMatchSel PmenuSel",
     "default link PmenuExtra Pmenu",
     "default link PmenuExtraSel PmenuSel",
+    "default link PopupSelected PmenuSel",
+    "default link MessageWindow WarningMsg",
+    "default link PopupNotification WarningMsg",
     CENT("Normal cterm=NONE", "Normal gui=NONE"),
     NULL
 };

src/popupwin.c

@@ -696,9 +696,6 @@ popup_highlight_curline(win_T *wp)
 	if (!sign_exists_by_name(sign_name))
 	{
 	    char *linehl = "PopupSelected";
-
-	    if (syn_name2id((char_u *)linehl) == 0)
-		linehl = "PmenuSel";
 	    sign_define_by_name(sign_name, NULL, (char_u *)linehl, NULL, NULL, NULL,
 		    NULL, SIGN_DEF_PRIO);
 	}
@@ -2006,10 +2003,8 @@ popup_update_color(win_T *wp, create_type_T type)
 {
     char    *hiname = type == TYPE_MESSAGE_WIN
 				       ? "MessageWindow" : "PopupNotification";
-    int		nr = syn_name2id((char_u *)hiname);
-
     set_string_option_direct_in_win(wp, (char_u *)"wincolor", -1,
-		(char_u *)(nr == 0 ? "WarningMsg" : hiname),
+		(char_u *)hiname,
 		OPT_FREE|OPT_LOCAL, 0);
 }
 

src/testdir/dumps/Test_popupwin_notify_02.dump

@@ -1,6 +1,6 @@
->1+0&#ffffff0| @7|╔+0#e000002&|═@21|╗| +0#0000000&@41
-|2| @7|║+0#e000002&| |f|i|r|s|t| |n|o|t|i|f|i|c|a|t|i|o|n| @2|║| +0#0000000&@41
-|3| @7|╚+0#e000002&|═@21|╝| +0#0000000&@41
+>1+0&#ffffff0| @7|╔+0&#5fd7ff255|═@21|╗| +0&#ffffff0@41
+|2| @7|║+0&#5fd7ff255| |f|i|r|s|t| |n|o|t|i|f|i|c|a|t|i|o|n| @2|║| +0&#ffffff0@41
+|3| @7|╚+0&#5fd7ff255|═@21|╝| +0&#ffffff0@41
 |4| @7|╔+0&#5fd7ff255|═@31|╗| +0&#ffffff0@31
 |5| @7|║+0&#5fd7ff255| |a|n|o|t|h|e|r| |i|m|p|o|r|t|a|n|t| |n|o|t|i|f|i|c|a|t|i|o|n| |║| +0&#ffffff0@31
 |6| @7|╚+0&#5fd7ff255|═@31|╝| +0&#ffffff0@31

src/version.c

@@ -704,6 +704,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1123,
 /**/
     1122,
 /**/