vim-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 vim/vim#7177)
b53e13a91a

N/A patches for version.c:

vim-patch:8.1.1877: graduated features scattered

Problem:    Graduated features scattered.
Solution:   Put graduated and obsolete features together.
ffc0716af8

vim-patch:8.2.1875: warning when building GTK gui

Problem:    Warning when building GTK gui.
Solution:   Add missing function parameter.
3da855c8e2

vim-patch:8.2.1877: test for function list fails

Problem:    Test for function list fails.
Solution:   Move "obsolete" comments one line up.
b8f519e538

vim-patch:8.2.1878: GTK: error for redefining function

Problem:    GTK: error for redefining function. (Tony Mechelynck)
Solution:   Remove "gtk_" prefix from local functions and prepend "gui_" to
            global functions.
8a99e66b4f

vim-patch:8.2.1881: cannot build with GTK3

Problem:    Cannot build with GTK3.
Solution:   Adjust form functions.
692d1a51e7

vim-patch:8.2.1883: compiler warnings when using Python

Problem:    Compiler warnings when using Python.
Solution:   Adjust PyCFunction to also have the second argument.  Use "int"
            return type for some functions.  Insert "(void *)" to get rid of
            the remaining warnings.
4ce5fe4c87

runtime/doc/autocmd.txt

@@ -700,9 +700,14 @@ 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/nvim/auevents.lua

@@ -65,7 +65,8 @@ return {
     'InsertChange',           -- when changing Insert/Replace mode
     'InsertCharPre',          -- before inserting a char
     'InsertEnter',            -- when entering Insert mode
-    'InsertLeave',            -- when leaving Insert mode
+    'InsertLeave',            -- just after leaving Insert mode
+    'InsertLeavePre',         -- just before leaving Insert mode
     'MenuPopup',              -- just before popup menu is displayed
     'OptionSet',              -- after setting any option
     'QuickFixCmdPost',        -- after :make, :grep etc.

src/nvim/edit.c

@@ -7691,6 +7691,10 @@ static bool ins_esc(long *count, int cmdchar, bool nomove)
     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/nvim/testdir/test_edit.vim

@@ -1441,31 +1441,40 @@ 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