vim-patch:8.1.1418: win_execute() is not implemented yet

Problem:    Win_execute() is not implemented yet.
Solution:   Implement it.
868b7b6712

runtime/doc/eval.txt

@@ -2498,6 +2498,8 @@ visualmode([expr])		String	last visual mode used
 wait({timeout}, {condition}[, {interval}])
 				Number  Wait until {condition} is satisfied
 wildmenumode()			Number	whether 'wildmenu' mode is active
+win_execute({id}, {command} [, {silent}])
+				String	execute {command} in window {id}
 win_findbuf({bufnr})		List	find windows containing {bufnr}
 win_getid([{win} [, {tab}]])	Number	get |window-ID| for {win} in {tab}
 win_gettype([{nr}])		String	type of window {nr}
@@ -3616,6 +3618,8 @@ execute({command} [, {silent}])				*execute()*
 		Note: If nested, an outer execute() will not observe output of
 		the inner calls.
 		Note: Text attributes (highlights) are not captured.
+		To execute a command in another window than the current one
+		use `win_execute()`.
 
 exepath({expr})						*exepath()*
 		Returns the full path of {expr} if it is an executable and
@@ -9477,6 +9481,12 @@ wildmenumode()					*wildmenumode()*
 <
 		(Note, this needs the 'wildcharm' option set appropriately).
 
+win_execute({id}, {command} [, {silent}])		*win_execute()*
+		Like `execute()` but in the context of window {id}.
+		The window will temporarily be made the current window,
+		without triggering autocommands.
+		Example: >
+			call win_execute(winid, 'syntax enable')
 
 win_findbuf({bufnr})					*win_findbuf()*
 		Returns a list with |window-ID|s for windows that contain

src/nvim/eval.lua

@@ -390,6 +390,7 @@ return {
     visualmode={args={0, 1}},
     wait={args={2,3}},
     wildmenumode={},
+    win_execute={args={2, 3}},
     win_findbuf={args=1},
     win_getid={args={0,2}},
     win_gettype={args={0,1}},

src/nvim/eval/funcs.c

@@ -1953,8 +1953,8 @@ static char_u *get_list_line(int c, void *cookie, int indent, bool do_concat)
   return (char_u *)(s == NULL ? NULL : xstrdup(s));
 }
 
-// "execute(command)" function
-static void f_execute(typval_T *argvars, typval_T *rettv, FunPtr fptr)
+static void execute_common(typval_T *argvars, typval_T *rettv, FunPtr fptr,
+                           int arg_off)
 {
   const int save_msg_silent = msg_silent;
   const int save_emsg_silent = emsg_silent;
@@ -1968,9 +1968,9 @@ static void f_execute(typval_T *argvars, typval_T *rettv, FunPtr fptr)
     return;
   }
 
-  if (argvars[1].v_type != VAR_UNKNOWN) {
+  if (argvars[arg_off + 1].v_type != VAR_UNKNOWN) {
     char buf[NUMBUFLEN];
-    const char *const s = tv_get_string_buf_chk(&argvars[1], buf);
+    const char *const s = tv_get_string_buf_chk(&argvars[arg_off + 1], buf);
 
     if (s == NULL) {
       return;
@@ -1997,10 +1997,10 @@ static void f_execute(typval_T *argvars, typval_T *rettv, FunPtr fptr)
     msg_col = 0;  // prevent leading spaces
   }
 
-  if (argvars[0].v_type != VAR_LIST) {
-    do_cmdline_cmd(tv_get_string(&argvars[0]));
-  } else if (argvars[0].vval.v_list != NULL) {
-    list_T *const list = argvars[0].vval.v_list;
+  if (argvars[arg_off].v_type != VAR_LIST) {
+    do_cmdline_cmd(tv_get_string(&argvars[arg_off]));
+  } else if (argvars[arg_off].vval.v_list != NULL) {
+    list_T *const list = argvars[arg_off].vval.v_list;
     tv_list_ref(list);
     GetListLineCookie cookie = {
       .l = list,
@@ -2032,6 +2032,30 @@ static void f_execute(typval_T *argvars, typval_T *rettv, FunPtr fptr)
   capture_ga = save_capture_ga;
 }
 
+// "execute(command)" function
+static void f_execute(typval_T *argvars, typval_T *rettv, FunPtr fptr)
+{
+  execute_common(argvars, rettv, fptr, 0);
+}
+
+// "win_execute(win_id, command)" function
+static void f_win_execute(typval_T *argvars, typval_T *rettv, FunPtr fptr)
+{
+  win_T *wp = win_id2wp(argvars);
+  win_T *save_curwin = curwin;
+
+  if (wp != NULL) {
+    curwin = wp;
+    curbuf = curwin->w_buffer;
+    check_cursor();
+    execute_common(argvars, rettv, fptr, 1);
+    if (win_valid(save_curwin)) {
+        curwin = save_curwin;
+        curbuf = curwin->w_buffer;
+    }
+  }
+}
+
 /// "exepath()" function
 static void f_exepath(typval_T *argvars, typval_T *rettv, FunPtr fptr)
 {

src/nvim/testdir/test_execute_func.vim

@@ -82,3 +82,27 @@ func Test_execute_not_silent()
   endfor
   call assert_equal('xyz ', text2)
 endfunc
+
+func Test_win_execute()
+  let thiswin = win_getid()
+  new
+  let otherwin = win_getid()
+  call setline(1, 'the new window')
+  call win_gotoid(thiswin)
+  let line = win_execute(otherwin, 'echo getline(1)')
+  call assert_match('the new window', line)
+
+  if has('textprop')
+    let popupwin = popup_create('the popup win', {'line': 2, 'col': 3})
+    redraw
+    let line = win_execute(popupwin, 'echo getline(1)')
+    call assert_match('the popup win', line)
+
+    call assert_fails('call win_execute(popupwin, "bwipe!")', 'E937:')
+
+    call popup_close(popupwin)
+  endif
+
+  call win_gotoid(otherwin)
+  bwipe!
+endfunc

test/functional/ui/float_spec.lua

@@ -62,6 +62,24 @@ describe('float window', function()
     eq(1000, funcs.win_getid())
   end)
 
+  it('win_execute() should work' , function()
+    local buf = meths.create_buf(false, false)
+    meths.buf_set_lines(buf, 0, -1, true, {'the floatwin'})
+    local win = meths.open_win(buf, false, {relative='win', width=16, height=1, row=0, col=10})
+    local line = funcs.win_execute(win, 'echo getline(1)')
+    eq('\nthe floatwin', line)
+    funcs.win_execute(win, 'bwipe!')
+  end)
+
+  it('win_execute() call commands that not allowed' , function()
+    local buf = meths.create_buf(false, false)
+    meths.buf_set_lines(buf, 0, -1, true, {'the floatwin'})
+    local win = meths.open_win(buf, true, {relative='win', width=16, height=1, row=0, col=10})
+    eq(pcall_err(funcs.win_execute, win, 'close'), 'Vim(close):E37: No write since last change (add ! to override)')
+    eq(pcall_err(funcs.win_execute, win, 'bdelete'), 'Vim(bdelete):E89: No write since last change for buffer 2 (add ! to override)')
+    funcs.win_execute(win, 'bwipe!')
+  end)
+
   it('closed immediately by autocmd #11383', function()
     eq('Error executing lua: [string "<nvim>"]:0: Window was closed immediately',
       pcall_err(exec_lua, [[