fix(events): avoid unnecessary CursorMoved (#24675)

Problem:    Temporarily changing current window in a script causes
            CursorMoved to be triggerd.
Solution:   Don't trigger CursorMoved if neither curwin nor cursor
            changed between two checks.

runtime/doc/vim_diff.txt

@@ -455,7 +455,7 @@ coerced to strings. See |id()| for more details, currently it uses
 
 |c_CTRL-R| pasting a non-special register into |cmdline| omits the last <CR>.
 
-|CursorMoved| always triggers when moving between windows.
+|CursorMoved| triggers when moving between windows.
 
 Lua interface (|lua.txt|):
 

src/nvim/autocmd.c

@@ -1030,7 +1030,8 @@ int autocmd_register(int64_t id, event_T event, const char *pat, int patlen, int
     // If the event is CursorMoved, update the last cursor position
     // position to avoid immediately triggering the autocommand
     if (event == EVENT_CURSORMOVED && !has_event(EVENT_CURSORMOVED)) {
-      curwin->w_last_cursormoved = curwin->w_cursor;
+      last_cursormoved_win = curwin;
+      last_cursormoved = curwin->w_cursor;
     }
 
     // Initialize the fields checked by the WinScrolled and

src/nvim/autocmd.h

@@ -80,6 +80,11 @@ typedef kvec_t(AutoCmd) AutoCmdVec;
 // apply_autocmds_group.
 EXTERN bool au_did_filetype INIT(= false);
 
+/// For CursorMoved event
+EXTERN win_T *last_cursormoved_win INIT(= NULL);
+/// For CursorMoved event, only used when last_cursormoved_win == curwin
+EXTERN pos_T last_cursormoved INIT(= { 0, 0, 0 });
+
 #ifdef INCLUDE_GENERATED_DECLARATIONS
 # include "autocmd.h.generated.h"
 #endif

src/nvim/buffer_defs.h

@@ -1101,7 +1101,6 @@ struct window_S {
                                     ///< can be different from w_cursor.lnum
                                     ///< for closed folds.
   linenr_T w_last_cursorline;       ///< where last 'cursorline' was drawn
-  pos_T w_last_cursormoved;         ///< for CursorMoved event
 
   // the next seven are used to update the visual part
   char w_old_visual_mode;           ///< last known VIsual_mode

src/nvim/change.c

@@ -361,9 +361,10 @@ static void changed_common(linenr_T lnum, colnr_T col, linenr_T lnume, linenr_T
   }
 
   // when the cursor line is changed always trigger CursorMoved
-  if (lnum <= curwin->w_cursor.lnum
+  if (last_cursormoved_win == curwin
+      && lnum <= curwin->w_cursor.lnum
       && lnume + (xtra < 0 ? -xtra : xtra) > curwin->w_cursor.lnum) {
-    curwin->w_last_cursormoved.lnum = 0;
+    last_cursormoved.lnum = 0;
   }
 }
 

src/nvim/edit.c

@@ -1287,7 +1287,8 @@ void ins_redraw(bool ready)
   // Trigger CursorMoved if the cursor moved.  Not when the popup menu is
   // visible, the command might delete it.
   if (ready && has_event(EVENT_CURSORMOVEDI)
-      && !equalpos(curwin->w_last_cursormoved, curwin->w_cursor)
+      && (last_cursormoved_win != curwin
+          || !equalpos(last_cursormoved, curwin->w_cursor))
       && !pum_visible()) {
     // Need to update the screen first, to make sure syntax
     // highlighting is correct after making a change (e.g., inserting
@@ -1300,7 +1301,8 @@ void ins_redraw(bool ready)
     // getcurpos()
     update_curswant();
     ins_apply_autocmds(EVENT_CURSORMOVEDI);
-    curwin->w_last_cursormoved = curwin->w_cursor;
+    last_cursormoved_win = curwin;
+    last_cursormoved = curwin->w_cursor;
   }
 
   // Trigger TextChangedI if changedtick differs.

src/nvim/normal.c

@@ -1267,9 +1267,11 @@ static void normal_check_cursor_moved(NormalState *s)
 {
   // Trigger CursorMoved if the cursor moved.
   if (!finish_op && has_event(EVENT_CURSORMOVED)
-      && !equalpos(curwin->w_last_cursormoved, curwin->w_cursor)) {
+      && (last_cursormoved_win != curwin
+          || !equalpos(last_cursormoved, curwin->w_cursor))) {
     apply_autocmds(EVENT_CURSORMOVED, NULL, NULL, false, curbuf);
-    curwin->w_last_cursormoved = curwin->w_cursor;
+    last_cursormoved_win = curwin;
+    last_cursormoved = curwin->w_cursor;
   }
 }
 

src/nvim/window.c

@@ -4943,7 +4943,6 @@ static void win_enter_ext(win_T *const wp, const int flags)
     if (other_buffer) {
       apply_autocmds(EVENT_BUFENTER, NULL, NULL, false, curbuf);
     }
-    curwin->w_last_cursormoved.lnum = 0;
   }
 
   maketitle();

test/functional/autocmd/cursormoved_spec.lua

@@ -3,7 +3,7 @@ local helpers = require('test.functional.helpers')(after_each)
 local clear = helpers.clear
 local eq = helpers.eq
 local eval = helpers.eval
-local funcs = helpers.funcs
+local meths = helpers.meths
 local source = helpers.source
 local command = helpers.command
 
@@ -12,10 +12,10 @@ describe('CursorMoved', function()
 
   it('is triggered after BufEnter when changing or splitting windows #11878 #12031', function()
     source([[
-    call setline(1, 'foo')
-    let g:log = []
-    autocmd BufEnter * let g:log += ['BufEnter' .. expand("<abuf>")]
-    autocmd CursorMoved * let g:log += ['CursorMoved' .. expand("<abuf>")]
+      call setline(1, 'foo')
+      let g:log = []
+      autocmd BufEnter * let g:log += ['BufEnter' .. expand("<abuf>")]
+      autocmd CursorMoved * let g:log += ['CursorMoved' .. expand("<abuf>")]
     ]])
     eq({}, eval('g:log'))
     command('new')
@@ -24,23 +24,34 @@ describe('CursorMoved', function()
     eq({'BufEnter2', 'CursorMoved2', 'BufEnter1', 'CursorMoved1'}, eval('g:log'))
   end)
 
+  it('is not triggered by temporarily switching window', function()
+    source([[
+      let g:cursormoved = 0
+      vnew
+      autocmd CursorMoved * let g:cursormoved += 1
+    ]])
+    command('wincmd w | wincmd p')
+    eq(0, eval('g:cursormoved'))
+  end)
+
   it("is not triggered by functions that don't change the window", function()
     source([[
-    let g:cursormoved = 0
-    let g:buf = bufnr('%')
-    vsplit foo
-    autocmd CursorMoved * let g:cursormoved += 1
-    call nvim_buf_set_lines(g:buf, 0, -1, v:true, ['aaa'])
+      let g:cursormoved = 0
+      let g:buf = bufnr('%')
+      vsplit foo
+      autocmd CursorMoved * let g:cursormoved += 1
     ]])
-    eq({'aaa'}, funcs.nvim_buf_get_lines(eval('g:buf'), 0, -1, true))
+    meths.buf_set_lines(eval('g:buf'), 0, -1, true, {'aaa'})
+    eq(0, eval('g:cursormoved'))
+    eq({'aaa'}, meths.buf_get_lines(eval('g:buf'), 0, -1, true))
     eq(0, eval('g:cursormoved'))
   end)
 
   it("is not triggered by cursor movement prior to first CursorMoved instantiation", function()
     source([[
-    let g:cursormoved = 0
-    autocmd! CursorMoved
-    autocmd CursorMoved * let g:cursormoved += 1
+      let g:cursormoved = 0
+      autocmd! CursorMoved
+      autocmd CursorMoved * let g:cursormoved += 1
     ]])
     eq(0, eval('g:cursormoved'))
   end)