patch 8.1.1673: cannot easily find the popup window at a certain position

Problem:    Cannot easily find the popup window at a certain position.
Solution:   Add popup_locate().

runtime/doc/popup.txt

@@ -170,6 +170,7 @@ Filter functions:
 Other:
 	|popup_getoptions()|	get current options for a popup
 	|popup_getpos()|	get actual position and size of a popup
+	|popup_locate()|	find popup window at a screen position
 
 
 DETAILS						*popup-function-details*
@@ -343,6 +344,13 @@ popup_hide({id})						*popup_hide()*
 		exists but is not a popup window an error is given. *E993*
 
 
+popup_locate({row}, {col})				 *popup_locate()*
+		Return the |window-ID| of the popup at screen positoin {row}
+		and {col}.  If there are multiple popups the one with the
+		highest zindex is returned.  If there are no popups at this
+		position then zero is returned.
+
+
 popup_menu({what}, {options})				 *popup_menu()*
 		Show the {what} near the cursor, handle selecting one of the
 		items with cursorkeys, and close it an item is selected with

src/evalfunc.c

@@ -781,6 +781,7 @@ static struct fst
     {"popup_getoptions", 1, 1, f_popup_getoptions},
     {"popup_getpos",	1, 1, f_popup_getpos},
     {"popup_hide",	1, 1, f_popup_hide},
+    {"popup_locate",	2, 2, f_popup_locate},
     {"popup_menu",	2, 2, f_popup_menu},
     {"popup_move",	2, 2, f_popup_move},
     {"popup_notification", 2, 2, f_popup_notification},

src/popupwin.c

@@ -1890,6 +1890,20 @@ f_popup_getpos(typval_T *argvars, typval_T *rettv)
 		      win_valid(wp) && (wp->w_popup_flags & POPF_HIDDEN) == 0);
     }
 }
+/*
+ * popup_locate({row}, {col})
+ */
+    void
+f_popup_locate(typval_T *argvars, typval_T *rettv)
+{
+    int		row = tv_get_number(&argvars[0]) - 1;
+    int		col = tv_get_number(&argvars[1]) - 1;
+    win_T	*wp;
+
+    wp = mouse_find_win(&row, &col, FIND_POPUP);
+    if (WIN_IS_POPUP(wp))
+	rettv->vval.v_number = wp->w_id;
+}
 
 /*
  * For popup_getoptions(): add a "border" or "padding" entry to "dict".

src/proto/popupwin.pro

@@ -29,6 +29,7 @@ void close_all_popups(void);
 void f_popup_move(typval_T *argvars, typval_T *rettv);
 void f_popup_setoptions(typval_T *argvars, typval_T *rettv);
 void f_popup_getpos(typval_T *argvars, typval_T *rettv);
+void f_popup_locate(typval_T *argvars, typval_T *rettv);
 void f_popup_getoptions(typval_T *argvars, typval_T *rettv);
 int error_if_popup_window(void);
 void popup_reset_handled(void);

src/testdir/test_popupwin.vim

@@ -713,7 +713,7 @@ func Test_popup_time()
   topleft vnew
   call setline(1, 'hello')
 
-  call popup_create('world', {
+  let winid = popup_create('world', {
 	\ 'line': 1,
 	\ 'col': 1,
 	\ 'minwidth': 20,
@@ -723,6 +723,11 @@ func Test_popup_time()
   let line = join(map(range(1, 5), 'screenstring(1, v:val)'), '')
   call assert_equal('world', line)
 
+  call assert_equal(winid, popup_locate(1, 1))
+  call assert_equal(winid, popup_locate(1, 20))
+  call assert_equal(0, popup_locate(1, 21))
+  call assert_equal(0, popup_locate(2, 1))
+
   sleep 700m
   redraw
   let line = join(map(range(1, 5), 'screenstring(1, v:val)'), '')

src/version.c

@@ -777,6 +777,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1673,
 /**/
     1672,
 /**/