Add TabClosed event

TabClosed is triggered when a tab page closes.

runtime/doc/autocmd.txt

@@ -298,6 +298,7 @@ Name			triggered by ~
 |TabLeave|		before leaving a tab page
 |TabNew|		when creating a new tab page
 |TabNewEntered|		after entering a new tab page
+|TabClosed|		after closing a tab page
 |CmdwinEnter|		after entering the command-line window
 |CmdwinLeave|		before leaving the command-line window
 
@@ -867,6 +868,9 @@ TabNew				When creating a new tab page. |tab-page|
 							*TabNewEntered*
 TabNewEntered			After entering a new tab page. |tab-page|
 				After BufEnter.
+							*TabClosed*
+TabClosed			After closing a tab page. <afile> can be used
+				for the tab page number.
 							*TermChanged*
 TermChanged			After the value of 'term' has changed.  Useful
 				for re-loading the syntax file to update the

runtime/syntax/vim.vim

@@ -76,7 +76,7 @@ syn keyword vimErrSetting contained	hardtabs ht w1200 w300 w9600
 
 " AutoCmd Events {{{2
 syn case ignore
-syn keyword vimAutoEvent contained	BufAdd BufCreate BufDelete BufEnter BufFilePost BufFilePre BufHidden BufLeave BufNew BufNewFile BufRead BufReadCmd BufReadPost BufReadPre BufUnload BufWinEnter BufWinLeave BufWipeout BufWrite BufWriteCmd BufWritePost BufWritePre Cmd-event CmdwinEnter CmdwinLeave ColorScheme CompleteDone CursorHold CursorHoldI CursorMoved CursorMovedI EncodingChanged FileAppendCmd FileAppendPost FileAppendPre FileChangedRO FileChangedShell FileChangedShellPost FileEncoding FileReadCmd FileReadPost FileReadPre FileType FileWriteCmd FileWritePost FileWritePre FilterReadPost FilterReadPre FilterWritePost FilterWritePre FocusGained FocusLost FuncUndefined GUIEnter GUIFailed InsertChange InsertCharPre InsertEnter InsertLeave JobActivity MenuPopup QuickFixCmdPost QuickFixCmdPre QuitPre RemoteReply SessionLoadPost ShellCmdPost ShellFilterPost SourceCmd SourcePre SpellFileMissing StdinReadPost StdinReadPre SwapExists Syntax TabEnter TabLeave TabNew TabNewEntered TermChanged TermResponse TextChanged TextChangedI User UserGettingBored VimEnter VimLeave VimLeavePre VimResized WinEnter WinLeave 
+syn keyword vimAutoEvent contained	BufAdd BufCreate BufDelete BufEnter BufFilePost BufFilePre BufHidden BufLeave BufNew BufNewFile BufRead BufReadCmd BufReadPost BufReadPre BufUnload BufWinEnter BufWinLeave BufWipeout BufWrite BufWriteCmd BufWritePost BufWritePre Cmd-event CmdwinEnter CmdwinLeave ColorScheme CompleteDone CursorHold CursorHoldI CursorMoved CursorMovedI EncodingChanged FileAppendCmd FileAppendPost FileAppendPre FileChangedRO FileChangedShell FileChangedShellPost FileEncoding FileReadCmd FileReadPost FileReadPre FileType FileWriteCmd FileWritePost FileWritePre FilterReadPost FilterReadPre FilterWritePost FilterWritePre FocusGained FocusLost FuncUndefined GUIEnter GUIFailed InsertChange InsertCharPre InsertEnter InsertLeave JobActivity MenuPopup QuickFixCmdPost QuickFixCmdPre QuitPre RemoteReply SessionLoadPost ShellCmdPost ShellFilterPost SourceCmd SourcePre SpellFileMissing StdinReadPost StdinReadPre SwapExists Syntax TabEnter TabLeave TabNew TabNewEntered TabClosed TermChanged TermResponse TextChanged TextChangedI User UserGettingBored VimEnter VimLeave VimLeavePre VimResized WinEnter WinLeave 
 
 " Highlight commonly used Groupnames {{{2
 syn keyword vimGroup contained	Comment Constant String Character Number Boolean Float Identifier Function Statement Conditional Repeat Label Operator Keyword Exception PreProc Include Define Macro PreCondit Type StorageClass Structure Typedef Special SpecialChar Tag Delimiter SpecialComment Debug Underlined Ignore Error Todo 

src/nvim/ex_docmd.c

@@ -5328,10 +5328,12 @@ void tabpage_close_other(tabpage_T *tp, int forceit)
   int done = 0;
   win_T       *wp;
   int h = tabline_height();
+  char_u prev_idx[NUMBUFLEN];
 
   /* Limit to 1000 windows, autocommands may add a window while we close
    * one.  OK, so I'm paranoid... */
   while (++done < 1000) {
+    sprintf((char *)prev_idx, "%i", tabpage_index(tp));
     wp = tp->tp_firstwin;
     ex_win_close(forceit, wp, tp);
 
@@ -5340,6 +5342,7 @@ void tabpage_close_other(tabpage_T *tp, int forceit)
     if (!valid_tabpage(tp) || tp->tp_firstwin == wp)
       break;
   }
+  apply_autocmds(EVENT_TABCLOSED, prev_idx, prev_idx, FALSE, curbuf);
 
   redraw_tabline = TRUE;
   if (h != tabline_height())

src/nvim/fileio.c

@@ -5245,6 +5245,7 @@ static struct event_name {
   {"StdinReadPre",    EVENT_STDINREADPRE},
   {"SwapExists",      EVENT_SWAPEXISTS},
   {"Syntax",          EVENT_SYNTAX},
+  {"TabClosed",       EVENT_TABCLOSED},
   {"TabEnter",        EVENT_TABENTER},
   {"TabLeave",        EVENT_TABLEAVE},
   {"TabNew",          EVENT_TABNEW},
@@ -6634,7 +6635,8 @@ apply_autocmds_group (
         || event == EVENT_QUICKFIXCMDPRE
         || event == EVENT_COLORSCHEME
         || event == EVENT_QUICKFIXCMDPOST
-        || event == EVENT_JOBACTIVITY)
+        || event == EVENT_JOBACTIVITY
+        || event == EVENT_TABCLOSED)
       fname = vim_strsave(fname);
     else
       fname = FullName_save(fname, FALSE);

src/nvim/fileio.h

@@ -93,6 +93,7 @@ typedef enum auto_event {
   EVENT_SPELLFILEMISSING,       /* spell file missing */
   EVENT_CURSORMOVED,            /* cursor was moved */
   EVENT_CURSORMOVEDI,           /* cursor was moved in Insert mode */
+  EVENT_TABCLOSED,               /* a tab has closed */
   EVENT_TABLEAVE,               /* before leaving a tab page */
   EVENT_TABENTER,               /* after entering a tab page */
   EVENT_TABNEW,                 /* when creating a new tab */

src/nvim/window.c

@@ -1791,6 +1791,9 @@ static int close_last_window_tabpage(win_T *win, int free_buf, tabpage_T *prev_c
   }
   /* Since goto_tabpage_tp above did not trigger *Enter autocommands, do
    * that now. */
+  char_u prev_idx[NUMBUFLEN];
+  sprintf((char *)prev_idx, "%i", tabpage_index(prev_curtab));
+  apply_autocmds(EVENT_TABCLOSED, prev_idx, prev_idx, FALSE, curbuf);
   apply_autocmds(EVENT_WINENTER, NULL, NULL, FALSE, curbuf);
   apply_autocmds(EVENT_TABENTER, NULL, NULL, FALSE, curbuf);
   if (old_curbuf != curbuf)

test/functional/autocmd/tabclose_spec.lua

@@ -0,0 +1,36 @@
+local helpers = require('test.functional.helpers')
+local clear, nvim, buffer, curbuf, curwin, eq, neq, ok =
+  helpers.clear, helpers.nvim, helpers.buffer, helpers.curbuf, helpers.curwin,
+  helpers.eq, helpers.neq, helpers.ok
+
+describe('TabClosed', function()
+    describe('au TabClosed', function()
+        describe('with * as <afile>', function()
+            it('matches when  closing any tab', function()
+                clear()
+                nvim('command', 'au! TabClosed * echom "tabclosed:".expand("<afile>").":".expand("<amatch>").":".tabpagenr()')
+                repeat 
+                    nvim('command',  'tabnew')
+                until nvim('eval', 'tabpagenr()') == 6 -- current tab is now 6
+                eq("\ntabclosed:6:6:5", nvim('command_output', 'tabclose')) -- close last 6, current tab is now 5
+                eq("\ntabclosed:5:5:4", nvim('command_output', 'close')) -- close last window on tab, closes tab
+                eq("\ntabclosed:2:2:3", nvim('command_output', '2tabclose')) -- close tab 2, current tab is now 3
+                eq("\ntabclosed:1:1:2\ntabclosed:1:1:1", nvim('command_output', 'tabonly')) -- close tabs 1 and 2
+            end)
+        end)
+        describe('with NR as <afile>', function()
+            it('matches when  closing a tab whose index is NR', function()
+                tmp_path = nvim('eval', 'tempname()')
+                nvim('command', 'au! TabClosed 2 echom "tabclosed:match"')
+                repeat 
+                    nvim('command',  'tabnew')
+                until nvim('eval', 'tabpagenr()') == 5 -- current tab is now 5
+                -- sanity check, we shouldn't match on tabs with numbers other than 2
+                eq("\ntabclosed:5:5:4", nvim('command_output', 'tabclose'))
+                -- close tab page 2, current tab is now 3
+                eq("\ntabclosed:2:2:3\ntabclosed:match", nvim('command_output', '2tabclose'))
+            end)
+        end)
+    end)
+end)
+