vim-patch:partial:9.1.0117: Stop split-moving from firing WinNew and WinNewPre autocommands

Problem:  win_splitmove fires WinNewPre and possibly WinNew when moving
          windows, even though no new windows are created.
Solution: don't fire WinNew and WinNewPre when inserting an existing
          window, even if it isn't the current window. Improve the
          accuracy of related documentation. (Sean Dewar)

96cc4aef3d

Partial as WinNewPre has not been ported yet (it currently has problems anyway).

runtime/doc/builtin.txt

@@ -8901,10 +8901,10 @@ win_screenpos({nr})                                            *win_screenpos()*
 		tabpage.
 
 win_splitmove({nr}, {target} [, {options}])                    *win_splitmove()*
-		Move the window {nr} to a new split of the window {target}.
-		This is similar to moving to {target}, creating a new window
-		using |:split| but having the same contents as window {nr}, and
-		then closing {nr}.
+		Temporarily switch to window {target}, then move window {nr}
+		to a new split adjacent to {target}.
+		Unlike commands such as |:split|, no new windows are created
+		(the |window-ID| of window {nr} is unchanged after the move).
 
 		Both {nr} and {target} can be window numbers or |window-ID|s.
 		Both must be in the current tab page.

runtime/doc/windows.txt

@@ -502,35 +502,33 @@ horizontally split windows.  CTRL-W H does it the other way around.
 
 						*CTRL-W_K*
 CTRL-W K	Move the current window to be at the very top, using the full
-		width of the screen.  This works like closing the current
-		window and then creating another one with ":topleft split",
-		except that the current window contents is used for the new
-		window.
+		width of the screen.  This works like `:topleft split`, except
+		it is applied to the current window and no new window is
+		created.
 
 						*CTRL-W_J*
 CTRL-W J	Move the current window to be at the very bottom, using the
-		full width of the screen.  This works like closing the current
-		window and then creating another one with ":botright split",
-		except that the current window contents is used for the new
-		window.
+		full width of the screen.  This works like `:botright split`,
+		except it is applied to the current window and no new window
+		is created.
 
 						*CTRL-W_H*
 CTRL-W H	Move the current window to be at the far left, using the
-		full height of the screen.  This works like closing the
-		current window and then creating another one with
-		`:vert topleft split`, except that the current window contents
-		is used for the new window.
+		full height of the screen.  This works like
+		`:vert topleft split`, except it is applied to the current
+		window and no new window is created.
 
 						*CTRL-W_L*
 CTRL-W L	Move the current window to be at the far right, using the full
-		height of the screen.  This works like closing the
-		current window and then creating another one with
-		`:vert botright split`, except that the current window
-		contents is used for the new window.
+		height of the screen.  This works like `:vert botright split`,
+		except it is applied to the current window and no new window
+		is created.
 
 						*CTRL-W_T*
 CTRL-W T	Move the current window to a new tab page.  This fails if
 		there is only one window in the current tab page.
+		This works like `:tab split`, except the previous window is
+		closed.
 		When a count is specified the new tab page will be opened
 		before the tab page with this index.  Otherwise it comes after
 		the current tab page.

runtime/lua/vim/_meta/vimfn.lua

@@ -10598,10 +10598,10 @@ function vim.fn.win_move_statusline(nr, offset) end
 --- @return any
 function vim.fn.win_screenpos(nr) end
 
---- Move the window {nr} to a new split of the window {target}.
---- This is similar to moving to {target}, creating a new window
---- using |:split| but having the same contents as window {nr}, and
---- then closing {nr}.
+--- Temporarily switch to window {target}, then move window {nr}
+--- to a new split adjacent to {target}.
+--- Unlike commands such as |:split|, no new windows are created
+--- (the |window-ID| of window {nr} is unchanged after the move).
 ---
 --- Both {nr} and {target} can be window numbers or |window-ID|s.
 --- Both must be in the current tab page.

src/nvim/eval.lua

@@ -12699,10 +12699,10 @@ M.funcs = {
     args = { 2, 3 },
     base = 1,
     desc = [=[
-      Move the window {nr} to a new split of the window {target}.
-      This is similar to moving to {target}, creating a new window
-      using |:split| but having the same contents as window {nr}, and
-      then closing {nr}.
+      Temporarily switch to window {target}, then move window {nr}
+      to a new split adjacent to {target}.
+      Unlike commands such as |:split|, no new windows are created
+      (the |window-ID| of window {nr} is unchanged after the move).
 
       Both {nr} and {target} can be window numbers or |window-ID|s.
       Both must be in the current tab page.

src/nvim/window.c

@@ -987,6 +987,8 @@ int win_split(int size, int flags)
 /// When "new_wp" is NULL: split the current window in two.
 /// When "new_wp" is not NULL: insert this window at the far
 /// top/left/right/bottom.
+/// On failure, if "new_wp" was not NULL, no changes will have been made to the
+/// window layout or sizes.
 /// @return  NULL for failure, or pointer to new window
 win_T *win_split_ins(int size, int flags, win_T *new_wp, int dir)
 {
@@ -1494,7 +1496,7 @@ win_T *win_split_ins(int size, int flags, win_T *new_wp, int dir)
 
   if (!(flags & WSP_NOENTER)) {
     // make the new window the current window
-    win_enter_ext(wp, WEE_TRIGGER_NEW_AUTOCMDS | WEE_TRIGGER_ENTER_AUTOCMDS
+    win_enter_ext(wp, (new_wp == NULL ? WEE_TRIGGER_NEW_AUTOCMDS : 0) | WEE_TRIGGER_ENTER_AUTOCMDS
                   | WEE_TRIGGER_LEAVE_AUTOCMDS);
   }
   if (vertical) {

test/old/testdir/test_window_cmd.vim

@@ -1066,6 +1066,19 @@ func Test_win_splitmove()
   leftabove split b
   leftabove vsplit c
   leftabove split d
+
+  " win_splitmove doesn't actually create or close any windows, so expect an
+  " unchanged winid and no WinNew/WinClosed events, like :wincmd H/J/K/L.
+  let s:triggered = []
+  augroup WinSplitMove
+    au!
+    " Nvim: WinNewPre not ported yet. Also needs full port of v9.1.0117 to pass.
+    " au WinNewPre * let s:triggered += ['WinNewPre']
+    au WinNew * let s:triggered += ['WinNew', win_getid()]
+    au WinClosed * let s:triggered += ['WinClosed', str2nr(expand('<afile>'))]
+  augroup END
+  let winid = win_getid()
+
   call assert_equal(0, win_splitmove(winnr(), winnr('l')))
   call assert_equal(bufname(winbufnr(1)), 'c')
   call assert_equal(bufname(winbufnr(2)), 'd')
@@ -1088,6 +1101,11 @@ func Test_win_splitmove()
   call assert_equal(bufname(winbufnr(3)), 'a')
   call assert_equal(bufname(winbufnr(4)), 'd')
   call assert_fails('call win_splitmove(winnr(), winnr("k"), v:_null_dict)', 'E1297:')
+  call assert_equal([], s:triggered)
+  call assert_equal(winid, win_getid())
+
+  unlet! s:triggered
+  au! WinSplitMove
   only | bd
 
   call assert_fails('call win_splitmove(winnr(), 123)', 'E957:')