# HG changeset patch
# User Christian Brabandt <cb@256bit.org>
# Date 1702731605 -3600
# Node ID f4d88db48a6340100fd6b66105c9143fc73925ce
# Parent  c82f521e9a43da1e80d5f9803052da62de66eac3
patch 9.0.2168: Moving tabpages on :drop may cause an endless loop

Commit: https://github.com/vim/vim/commit/df12e39b8b9dd39056e22b452276622cb7b617fd
Author: Christian Brabandt <cb@256bit.org>
Date:   Sat Dec 16 13:55:32 2023 +0100

    patch 9.0.2168: Moving tabpages on :drop may cause an endless loop

    Problem:  Moving tabpages on :drop may cause an endless loop
    Solution: Disallow moving tabpages on :drop when cleaning up the arglist
              first

    Moving tabpages during drop command may cause an endless loop

    When executing a :tab drop command, Vim will close all windows not in
    the argument list. This triggers various autocommands. If a user has
    created an 'au Tabenter * :tabmove -' autocommand, this can cause Vim to
    end up in an endless loop, when trying to iterate over all tabs (which
    would trigger the tabmove autocommand, which will change the tpnext
    pointer, etc).

    So instead of blocking all autocommands before we actually try to edit
    the given file, lets simply disallow to move tabpages around. Otherwise,
    we may change the expected number of events triggered during a :drop
    command, which users may rely on (there is actually a test, that expects
    various TabLeave/TabEnter autocommands) and would therefore be a
    backwards incompatible change.

    Don't make this an error, as this could trigger several times during the
    drop command, but silently ignore the :tabmove command in this case (and
    it should in fact finally trigger successfully when loading the given
    file in a new tab). So let's just be quiet here instead.

    fixes:  #13676
    closes: #13686

    Signed-off-by: Christian Brabandt <cb@256bit.org>

diff --git a/src/arglist.c b/src/arglist.c
--- a/src/arglist.c
+++ b/src/arglist.c
@@ -983,6 +983,9 @@ arg_all_close_unused_windows(arg_all_sta
 
     if (aall->had_tab > 0)
 	goto_tabpage_tp(first_tabpage, TRUE, TRUE);
+
+    // moving tabpages around in an autocommand may cause an endless loop
+    tabpage_move_disallowed++;
     for (;;)
     {
 	tpnext = curtab->tp_next;
@@ -1093,6 +1096,7 @@ arg_all_close_unused_windows(arg_all_sta
 
 	goto_tabpage_tp(tpnext, TRUE, TRUE);
     }
+    tabpage_move_disallowed--;
 }
 
 /*
diff --git a/src/globals.h b/src/globals.h
--- a/src/globals.h
+++ b/src/globals.h
@@ -792,8 +792,9 @@ EXTERN int	is_mac_terminal INIT(= FALSE)
 #endif
 
 EXTERN int	autocmd_busy INIT(= FALSE);	// Is apply_autocmds() busy?
-EXTERN int	autocmd_no_enter INIT(= FALSE); // *Enter autocmds disabled
-EXTERN int	autocmd_no_leave INIT(= FALSE); // *Leave autocmds disabled
+EXTERN int	autocmd_no_enter INIT(= FALSE); // Buf/WinEnter autocmds disabled
+EXTERN int	autocmd_no_leave INIT(= FALSE); // Buf/WinLeave autocmds disabled
+EXTERN int	tabpage_move_disallowed INIT(= FALSE);  // moving tabpages around disallowed
 
 EXTERN int	modified_was_set;		// did ":set modified"
 EXTERN int	did_filetype INIT(= FALSE);	// FileType event found
diff --git a/src/testdir/test_tabpage.vim b/src/testdir/test_tabpage.vim
--- a/src/testdir/test_tabpage.vim
+++ b/src/testdir/test_tabpage.vim
@@ -903,4 +903,23 @@ func Test_tabpage_last_line()
   bwipe!
 endfunc
 
+" this was causing an endless loop
+func Test_tabpage_drop_tabmove()
+  augroup TestTabpageTabmove
+    au!
+    autocmd! TabEnter * :if tabpagenr() > 1 | tabmove - | endif
+  augroup end
+  $tab drop XTab_99.log
+  $tab drop XTab_98.log
+  $tab drop XTab_97.log
+
+  autocmd! TestTabpageTabmove
+  augroup! TestTabpageTabmove
+
+  " clean up
+  bwipe!
+  bwipe!
+  bwipe!
+endfunc
+
 " vim: shiftwidth=2 sts=2 expandtab
diff --git a/src/version.c b/src/version.c
--- a/src/version.c
+++ b/src/version.c
@@ -705,6 +705,8 @@ static char *(features[]) =
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    2168,
+/**/
     2167,
 /**/
     2166,
diff --git a/src/window.c b/src/window.c
--- a/src/window.c
+++ b/src/window.c
@@ -4970,6 +4970,9 @@ tabpage_move(int nr)
     if (first_tabpage->tp_next == NULL)
 	return;
 
+    if (tabpage_move_disallowed)
+	return;
+
     for (tp = first_tabpage; tp->tp_next != NULL && n < nr; tp = tp->tp_next)
 	++n;