vim-patch:9.1.1211: TabClosedPre is triggered just before the tab is being freed

Problem:  TabClosedPre is triggered just before the tab is being freed,
          which limited its functionality.
Solution: Trigger it a bit earlier and also on :tabclose and :tabonly
          (Jim Zhou)

closes: vim/vim#16890

bcf66e0141

Co-authored-by: Jim Zhou <jimzhouzzy@gmail.com>

src/nvim/ex_docmd.c

@@ -5150,6 +5150,8 @@ void tabpage_close(int forceit)
     return;
   }
 
+  trigger_tabclosedpre(curtab, true);
+
   // First close all the windows but the current one.  If that worked then
   // close the last window in this tab, that will close it.
   while (curwin->w_floating) {
@@ -5172,6 +5174,8 @@ void tabpage_close_other(tabpage_T *tp, int forceit)
   int done = 0;
   char prev_idx[NUMBUFLEN];
 
+  trigger_tabclosedpre(tp, true);
+
   // Limit to 1000 windows, autocommands may add a window while we close
   // one.  OK, so I'm paranoid...
   while (++done < 1000) {

src/nvim/window.c

@@ -3102,9 +3102,12 @@ static void do_autocmd_winclosed(win_T *win)
   recursive = false;
 }
 
-static void trigger_tabclosedpre(tabpage_T *tp)
+/// directly is true if the window is closed by ':tabclose' or ':tabonly'.
+/// This allows saving the session before closing multi-window tab.
+void trigger_tabclosedpre(tabpage_T *tp, bool directly)
 {
   static bool recursive = false;
+  static bool skip = false;
   tabpage_T *ptp = curtab;
 
   // Quickly return when no TabClosedPre autocommands to be executed or
@@ -3113,8 +3116,17 @@ static void trigger_tabclosedpre(tabpage_T *tp)
     return;
   }
 
+  // Skip if the event have been triggered by ':tabclose' recently
+  if (skip) {
+    skip = false;
+    return;
+  }
+
   if (valid_tabpage(tp)) {
     goto_tabpage_tp(tp, false, false);
+    if (directly) {
+      skip = true;
+    }
   }
   recursive = true;
   window_layout_lock();
@@ -3187,7 +3199,7 @@ bool win_close_othertab(win_T *win, int free_buf, tabpage_T *tp, bool force)
   }
 
   if (tp->tp_firstwin == tp->tp_lastwin) {
-    trigger_tabclosedpre(tp);
+    trigger_tabclosedpre(tp, false);
     // autocmd may have freed the window already.
     if (!win_valid_any_tab(win)) {
       return false;

test/old/testdir/test_autocmd.vim

@@ -4760,7 +4760,7 @@ func Test_autocmd_tabclosedpre()
   call ClearAutomcdAndCreateTabs()
   au TabClosedPre * tabmove 0
   tabclose
-  call assert_equal('1Z2A3>B', GetTabs())
+  call assert_equal('1>Z2A3B', GetTabs())
   call ClearAutomcdAndCreateTabs()
   au TabClosedPre * tabmove 0
   tabclose 1
@@ -4788,7 +4788,33 @@ func Test_autocmd_tabclosedpre()
   au TabClosedPre * new X | new Y | new Z
   call assert_fails('tabclose 1', 'E242')
 
+  " Test directly closing the tab page with ':tabclose'
+  au!
+  tabonly
+  bw!
+  e Z
+  au TabClosedPre * mksession!
+  tabnew A
+  sp
+  tabclose
+  source Session.vim
+  call assert_equal('1Z2>AA', GetTabs())
+
+  " Test directly closing the tab page with ':tabonly'
+  " Z is closed before A. Hence A overwrites the session.
+  au!
+  tabonly
+  bw!
+  e Z
+  au TabClosedPre * mksession!
+  tabnew A
+  tabnew B
+  tabonly
+  source Session.vim
+  call assert_equal('1>A2B', GetTabs())
+
   " Clean up
+  call delete('Session.vim')
   au!
   only
   tabonly