patch 8.2.1874: can't do something just before leaving Insert mode

Problem:    Can't do something just before leaving Insert mode.
Solution:   Add the InsertLeavePre autocommand event. (closes #7177)

runtime/doc/autocmd.txt

@@ -881,9 +881,14 @@ InsertEnter			Just before starting Insert mode.  Also for
 				The cursor is restored afterwards.  If you do
 				not want that set |v:char| to a non-empty
 				string.
+							*InsertLeavePre*
+InsertLeavePre			Just before leaving Insert mode.  Also when
+				using CTRL-O |i_CTRL-O|.  Be caseful not to
+				change mode or use `:normal`, it will likely
+				cause trouble.
 							*InsertLeave*
-InsertLeave			When leaving Insert mode.  Also when using
+InsertLeave			Just after leaving Insert mode.  Also when
-				CTRL-O |i_CTRL-O|.  But not for |i_CTRL-C|.
+				using CTRL-O |i_CTRL-O|.  But not for |i_CTRL-C|.
 							*MenuPopup*
 MenuPopup			Just before showing the popup menu (under the
 				right mouse button).  Useful for adjusting the

src/autocmd.c

@@ -149,6 +149,7 @@ static struct event_name
     {"InsertChange",	EVENT_INSERTCHANGE},
     {"InsertEnter",	EVENT_INSERTENTER},
     {"InsertLeave",	EVENT_INSERTLEAVE},
+    {"InsertLeavePre",	EVENT_INSERTLEAVEPRE},
     {"InsertCharPre",	EVENT_INSERTCHARPRE},
     {"MenuPopup",	EVENT_MENUPOPUP},
     {"OptionSet",	EVENT_OPTIONSET},

src/edit.c

@@ -3607,6 +3607,9 @@ ins_esc(
 	undisplay_dollar();
     }
 
+    if (cmdchar != 'r' && cmdchar != 'v')
+	ins_apply_autocmds(EVENT_INSERTLEAVEPRE);
+
     // When an autoindent was removed, curswant stays after the
     // indent
     if (restart_edit == NUL && (colnr_T)temp == curwin->w_cursor.col)

src/testdir/test_edit.vim

@@ -1446,31 +1446,40 @@ endfunc
 
 func Test_edit_InsertLeave()
   new
+  au InsertLeavePre * let g:did_au_pre = 1
   au InsertLeave * let g:did_au = 1
+  let g:did_au_pre = 0
   let g:did_au = 0
   call feedkeys("afoo\<Esc>", 'tx')
+  call assert_equal(1, g:did_au_pre)
   call assert_equal(1, g:did_au)
   call assert_equal('foo', getline(1))
 
+  let g:did_au_pre = 0
   let g:did_au = 0
   call feedkeys("Sbar\<C-C>", 'tx')
+  call assert_equal(1, g:did_au_pre)
   call assert_equal(0, g:did_au)
   call assert_equal('bar', getline(1))
 
   inoremap x xx<Esc>
+  let g:did_au_pre = 0
   let g:did_au = 0
   call feedkeys("Saax", 'tx')
+  call assert_equal(1, g:did_au_pre)
   call assert_equal(1, g:did_au)
   call assert_equal('aaxx', getline(1))
 
   inoremap x xx<C-C>
+  let g:did_au_pre = 0
   let g:did_au = 0
   call feedkeys("Sbbx", 'tx')
+  call assert_equal(1, g:did_au_pre)
   call assert_equal(0, g:did_au)
   call assert_equal('bbxx', getline(1))
 
   bwipe!
-  au! InsertLeave
+  au! InsertLeave InsertLeavePre
   iunmap x
 endfunc
 

src/version.c

@@ -750,6 +750,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1874,
 /**/
     1873,
 /**/

src/vim.h

@@ -1298,7 +1298,8 @@ enum auto_event
     EVENT_INSERTCHANGE,		// when changing Insert/Replace mode
     EVENT_INSERTCHARPRE,	// before inserting a char
     EVENT_INSERTENTER,		// when entering Insert mode
-    EVENT_INSERTLEAVE,		// when leaving Insert mode
+    EVENT_INSERTLEAVEPRE,	// just before leaving Insert mode
+    EVENT_INSERTLEAVE,		// just after leaving Insert mode
     EVENT_MENUPOPUP,		// just before popup menu is displayed
     EVENT_OPTIONSET,		// option was set
     EVENT_QUICKFIXCMDPOST,	// after :make, :grep etc.
@@ -1325,7 +1326,8 @@ enum auto_event
     EVENT_TABNEW,		// when entering a new tab page
     EVENT_TERMCHANGED,		// after changing 'term'
     EVENT_TERMINALOPEN,		// after a terminal buffer was created
-    EVENT_TERMINALWINOPEN,	// after a terminal buffer was created and entering its window
+    EVENT_TERMINALWINOPEN,	// after a terminal buffer was created and
+				// entering its window
     EVENT_TERMRESPONSE,		// after setting "v:termresponse"
     EVENT_TEXTCHANGED,		// text was modified not in Insert mode
     EVENT_TEXTCHANGEDI,         // text was modified in Insert mode