patch 8.2.0142: possible to enter popup window with CTRL-W p

Problem:    Possible to enter popup window with CTRL-W p. (John Devin)
Solution:   Check entered window is not a popup window. (closes #5515)

src/popupwin.c

@@ -2484,6 +2484,8 @@ popup_close_tabpage(tabpage_T *tp, int id)
     void
 close_all_popups(void)
 {
+    if (ERROR_IF_POPUP_WINDOW)
+	return;
     while (first_popupwin != NULL)
 	popup_close(first_popupwin->w_id);
     while (curtab->tp_first_popupwin != NULL)

src/testdir/dumps/Test_popupwin_previewpopup_10.dump

@@ -0,0 +1,14 @@
+|o+0&#ffffff0|n|e| @71
+|#|i|n|c|l|u|d|e| |"|X|h|e|a|d|e|r|.|h|"| @54
+|t|h|r|e@1| @69
+|f|o|u|r| @70
+|f|i|v|e| @28|╔+0#0000001#ffd7ff255| |X|h|e|a|d|e|r|.|h| |═@28|X
+|s+0#0000000#ffffff0|i|x| @29|║+0#0000001#ffd7ff255|1+0#e000002&|0| +0#0000001&@36| +0#0000000#a8a8a8255|║+0#0000001#ffd7ff255
+|s+0#0000000#ffffff0|e|v|e|n| @27|║+0#0000001#ffd7ff255|s|e|a|r|c|h|e|d| |w|o|r|d| |i|s| |h|e|r|e| @17| +0#0000000#a8a8a8255|║+0#0000001#ffd7ff255
+|f+0#0000000#ffffff0|i|n|d| |t|h|e|w|o|r|d| |s|o|m|e|w|h|e|r|e| @10|║+0#0000001#ffd7ff255|1+0#e000002&|2| +0#0000001&@36| +0#0000000#0000001|║+0#0000001#ffd7ff255
+|n+0#0000000#ffffff0|i|n|e| @28|║+0#0000001#ffd7ff255|1+0#e000002&|3| +0#0000001&@36| +0#0000000#a8a8a8255|║+0#0000001#ffd7ff255
+|t+0#0000000#ffffff0|h|i|s| |i|s| |a|n|o|t|h|e|r| |w|o|r|d| @12|╚+0#0000001#ffd7ff255|═@39|⇲
+|v+0#0000000#ffffff0|e|r|y| |l|o|n|g| |l|i|n|e| |w|h|e|r|e| |t|h|e| |w|o|r|d| |i|s| |a|l|s|o| >a|n|o|t|h|e|r| @29
+|~+0#4040ff13&| @73
+|~| @73
+|E+0#ffffff16#e000002|9@1|4|:| |N|o|t| |a|l@1|o|w|e|d| |i|n| |a| |p|o|p|u|p| |w|i|n|d|o|w| +0#0000000#ffffff0@21|1@1|,|3|9| @8|A|l@1| 

src/testdir/dumps/Test_popupwin_previewpopup_9.dump

@@ -0,0 +1,14 @@
+|o+0&#ffffff0|n|e| @71
+|#|i|n|c|l|u|d|e| |"|X|h|e|a|d|e|r|.|h|"| @54
+|t|h|r|e@1| @69
+|f|o|u|r| @70
+|f|i|v|e| @28|╔+0#0000001#ffd7ff255| |X|h|e|a|d|e|r|.|h| |═@28|X
+|s+0#0000000#ffffff0|i|x| @29|║+0#0000001#ffd7ff255|1+0#e000002&|0| +0#0000001&@36| +0#0000000#a8a8a8255|║+0#0000001#ffd7ff255
+|s+0#0000000#ffffff0|e|v|e|n| @27|║+0#0000001#ffd7ff255|s|e|a|r|c|h|e|d| |w|o|r|d| |i|s| |h|e|r|e| @17| +0#0000000#a8a8a8255|║+0#0000001#ffd7ff255
+|f+0#0000000#ffffff0|i|n|d| |t|h|e|w|o|r|d| |s|o|m|e|w|h|e|r|e| @10|║+0#0000001#ffd7ff255|1+0#e000002&|2| +0#0000001&@36| +0#0000000#0000001|║+0#0000001#ffd7ff255
+|n+0#0000000#ffffff0|i|n|e| @28|║+0#0000001#ffd7ff255|1+0#e000002&|3| +0#0000001&@36| +0#0000000#a8a8a8255|║+0#0000001#ffd7ff255
+|t+0#0000000#ffffff0|h|i|s| |i|s| |a|n|o|t|h|e|r| |w|o|r|d| @12|╚+0#0000001#ffd7ff255|═@39|⇲
+|v+0#0000000#ffffff0|e|r|y| |l|o|n|g| |l|i|n|e| |w|h|e|r|e| |t|h|e| |w|o|r|d| |i|s| |a|l|s|o| >a|n|o|t|h|e|r| @29
+|~+0#4040ff13&| @73
+|~| @73
+|E+0#ffffff16#e000002|3|6@1|:| |N|o|t| |a|l@1|o|w|e|d| |t|o| |e|n|t|e|r| |a| |p|o|p|u|p| |w|i|n|d|o|w| +0#0000000#ffffff0@15|1@1|,|3|9| @8|A|l@1| 

src/testdir/test_popupwin.vim

@@ -2804,6 +2804,12 @@ func Test_previewpopup()
   call term_sendkeys(buf, ":\<CR>")
   call VerifyScreenDump(buf, 'Test_popupwin_previewpopup_8', {})
 
+  call term_sendkeys(buf, "\<C-W>p")
+  call VerifyScreenDump(buf, 'Test_popupwin_previewpopup_9', {})
+
+  call term_sendkeys(buf, ":call win_execute(popup_findpreview(), 'call popup_clear()')\<CR>")
+  call VerifyScreenDump(buf, 'Test_popupwin_previewpopup_10', {})
+
   call StopVimInTerminal(buf)
   call delete('Xtags')
   call delete('Xtagfile')

src/version.c

@@ -742,6 +742,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    142,
 /**/
     141,
 /**/

src/window.c

@@ -4343,8 +4343,15 @@ win_goto(win_T *wp)
     win_T	*owp = curwin;
 #endif
 
+#ifdef FEAT_PROP_POPUP
     if (ERROR_IF_POPUP_WINDOW)
 	return;
+    if (popup_is_popup(wp))
+    {
+	emsg(_("E366: Not allowed to enter a popup window"));
+	return;
+    }
+#endif
     if (text_locked())
     {
 	beep_flush();