vim-patch:8.2.4018: ml_get error when win_execute redraws with Visual selection

Problem:    ml_get error when win_execute redraws with Visual selection.
Solution:   Disable Visual area temporarily. (closes vim/vim#9479)
https://github.com/vim/vim/commit/18f4740f043b353abe47b7a00131317052457686

{switch_to/restore}_win_for_buf is N/A (marked as such in v8.0.0860; currently
only used in Vim's if_py).

Add a modeline to test_execute_func.vim.

8 files changed, 79 insertions, 59 deletions

diff --git a/src/nvim/api/private/helpers.c b/src/nvim/api/private/helpers.c
index 4ddd90f3c9..ddcfff0097 100644
--- a/src/nvim/api/private/helpers.c
+++ b/src/nvim/api/private/helpers.c
@@ -989,18 +989,16 @@ Object copy_object(Object obj)
 static void set_option_value_for(char *key, int numval, char *stringval, int opt_flags,
                                  int opt_type, void *from, Error *err)
 {
-  win_T *save_curwin = NULL;
-  tabpage_T *save_curtab = NULL;
+  switchwin_T switchwin;
   aco_save_T aco;
 
   try_start();
   switch (opt_type)
   {
   case SREQ_WIN:
-    if (switch_win_noblock(&save_curwin, &save_curtab, (win_T *)from,
-                           win_find_tabpage((win_T *)from), true)
+    if (switch_win_noblock(&switchwin, (win_T *)from, win_find_tabpage((win_T *)from), true)
         == FAIL) {
-      restore_win_noblock(save_curwin, save_curtab, true);
+      restore_win_noblock(&switchwin, true);
       if (try_end(err)) {
         return;
       }
@@ -1010,7 +1008,7 @@ static void set_option_value_for(char *key, int numval, char *stringval, int opt
       return;
     }
     set_option_value_err(key, numval, stringval, opt_flags, err);
-    restore_win_noblock(save_curwin, save_curtab, true);
+    restore_win_noblock(&switchwin, true);
     break;
   case SREQ_BUF:
     aucmd_prepbuf(&aco, (buf_T *)from);
diff --git a/src/nvim/api/window.c b/src/nvim/api/window.c
index 907306da7b..a762673fbf 100644
--- a/src/nvim/api/window.c
+++ b/src/nvim/api/window.c
@@ -455,17 +455,14 @@ Object nvim_win_call(Window window, LuaRef fun, Error *err)
   }
   tabpage_T *tabpage = win_find_tabpage(win);
 
-  win_T *save_curwin;
-  tabpage_T *save_curtab;
-
   try_start();
   Object res = OBJECT_INIT;
-  if (switch_win_noblock(&save_curwin, &save_curtab, win, tabpage, true) ==
-      OK) {
+  switchwin_T switchwin;
+  if (switch_win_noblock(&switchwin, win, tabpage, true) == OK) {
     Array args = ARRAY_DICT_INIT;
     res = nlua_call_ref(fun, NULL, args, true, err);
   }
-  restore_win_noblock(save_curwin, save_curtab, true);
+  restore_win_noblock(&switchwin, true);
   try_end(err);
   return res;
 }
diff --git a/src/nvim/eval.c b/src/nvim/eval.c
index b8e9f41551..5d9326eb24 100644
--- a/src/nvim/eval.c
+++ b/src/nvim/eval.c
@@ -6963,10 +6963,9 @@ win_T *find_tabwin(typval_T *wvp, typval_T *tvp)
 /// @param off  1 for gettabwinvar()
 void getwinvar(typval_T *argvars, typval_T *rettv, int off)
 {
-  win_T *win, *oldcurwin;
+  win_T *win;
   dictitem_T *v;
   tabpage_T *tp = NULL;
-  tabpage_T *oldtabpage = NULL;
   bool done = false;
 
   if (off == 1) {
@@ -6986,8 +6985,8 @@ void getwinvar(typval_T *argvars, typval_T *rettv, int off)
     // otherwise the window is not valid. Only do this when needed,
     // autocommands get blocked.
     bool need_switch_win = tp != curtab || win != curwin;
-    if (!need_switch_win
-        || switch_win(&oldcurwin, &oldtabpage, win, tp, true) == OK) {
+    switchwin_T switchwin;
+    if (!need_switch_win || switch_win(&switchwin, win, tp, true) == OK) {
       if (*varname == '&') {
         if (varname[1] == NUL) {
           // get all window-local options in a dict
@@ -7015,7 +7014,7 @@ void getwinvar(typval_T *argvars, typval_T *rettv, int off)
 
     if (need_switch_win) {
       // restore previous notion of curwin
-      restore_win(oldcurwin, oldtabpage, true);
+      restore_win(&switchwin, true);
     }
   }
   emsg_off--;
@@ -7517,11 +7516,9 @@ void setwinvar(typval_T *argvars, typval_T *rettv, int off)
   typval_T *varp = &argvars[off + 2];
 
   if (win != NULL && varname != NULL && varp != NULL) {
-    win_T *save_curwin;
-    tabpage_T *save_curtab;
     bool need_switch_win = tp != curtab || win != curwin;
-    if (!need_switch_win
-        || switch_win(&save_curwin, &save_curtab, win, tp, true) == OK) {
+    switchwin_T switchwin;
+    if (!need_switch_win || switch_win(&switchwin, win, tp, true) == OK) {
       if (*varname == '&') {
         long numval;
         bool error = false;
@@ -7543,7 +7540,7 @@ void setwinvar(typval_T *argvars, typval_T *rettv, int off)
       }
     }
     if (need_switch_win) {
-      restore_win(save_curwin, save_curtab, true);
+      restore_win(&switchwin, true);
     }
   }
 }
diff --git a/src/nvim/eval/funcs.c b/src/nvim/eval/funcs.c
index 29619f62e9..3cfc00fea2 100644
--- a/src/nvim/eval/funcs.c
+++ b/src/nvim/eval/funcs.c
@@ -2176,20 +2176,18 @@ static void f_win_execute(typval_T *argvars, typval_T *rettv, FunPtr fptr)
 {
   tabpage_T *tp;
   win_T *wp = win_id2wp_tp(argvars, &tp);
-  win_T *save_curwin;
-  tabpage_T *save_curtab;
   // Return an empty string if something fails.
   rettv->v_type = VAR_STRING;
   rettv->vval.v_string = NULL;
 
   if (wp != NULL && tp != NULL) {
     pos_T curpos = wp->w_cursor;
-    if (switch_win_noblock(&save_curwin, &save_curtab, wp, tp, true) ==
-        OK) {
+    switchwin_T switchwin;
+    if (switch_win_noblock(&switchwin, wp, tp, true) == OK) {
       check_cursor();
       execute_common(argvars, rettv, fptr, 1);
     }
-    restore_win_noblock(save_curwin, save_curtab, true);
+    restore_win_noblock(&switchwin, true);
 
     // Update the status line if the cursor moved.
     if (win_valid(wp) && !equalpos(curpos, wp->w_cursor)) {
@@ -4031,8 +4029,6 @@ static void f_gettabinfo(typval_T *argvars, typval_T *rettv, FunPtr fptr)
  */
 static void f_gettabvar(typval_T *argvars, typval_T *rettv, FunPtr fptr)
 {
-  win_T *oldcurwin;
-  tabpage_T *oldtabpage;
   bool done = false;
 
   rettv->v_type = VAR_STRING;
@@ -4046,7 +4042,8 @@ static void f_gettabvar(typval_T *argvars, typval_T *rettv, FunPtr fptr)
     win_T *const window = tp == curtab || tp->tp_firstwin == NULL
         ? firstwin
         : tp->tp_firstwin;
-    if (switch_win(&oldcurwin, &oldtabpage, window, tp, true) == OK) {
+    switchwin_T switchwin;
+    if (switch_win(&switchwin, window, tp, true) == OK) {
       // look up the variable
       // Let gettabvar({nr}, "") return the "t:" dictionary.
       const dictitem_T *const v = find_var_in_ht(&tp->tp_vars->dv_hashtab, 't',
@@ -4059,7 +4056,7 @@ static void f_gettabvar(typval_T *argvars, typval_T *rettv, FunPtr fptr)
     }
 
     // restore previous notion of curwin
-    restore_win(oldcurwin, oldtabpage, true);
+    restore_win(&switchwin, true);
   }
 
   if (!done && argvars[2].v_type != VAR_UNKNOWN) {
@@ -5881,18 +5878,16 @@ static void f_line(typval_T *argvars, typval_T *rettv, FunPtr fptr)
 
   if (argvars[1].v_type != VAR_UNKNOWN) {
     tabpage_T *tp;
-    win_T *save_curwin;
-    tabpage_T *save_curtab;
 
     // use window specified in the second argument
     win_T *wp = win_id2wp_tp(&argvars[1], &tp);
     if (wp != NULL && tp != NULL) {
-      if (switch_win_noblock(&save_curwin, &save_curtab, wp, tp, true)
-          == OK) {
+      switchwin_T switchwin;
+      if (switch_win_noblock(&switchwin, wp, tp, true) == OK) {
         check_cursor();
         fp = var2fpos(&argvars[0], true, &fnum);
       }
-      restore_win_noblock(save_curwin, save_curtab, true);
+      restore_win_noblock(&switchwin, true);
     }
   } else {
     // use current window
diff --git a/src/nvim/move.c b/src/nvim/move.c
index 67ec19903f..27cc2b341c 100644
--- a/src/nvim/move.c
+++ b/src/nvim/move.c
@@ -346,10 +346,10 @@ void update_topline(win_T *wp)
  */
 void update_topline_win(win_T *win)
 {
-  win_T *save_curwin;
-  switch_win(&save_curwin, NULL, win, NULL, true);
+  switchwin_T switchwin;
+  switch_win(&switchwin, win, NULL, true);
   update_topline(curwin);
-  restore_win(save_curwin, NULL, true);
+  restore_win(&switchwin, true);
 }
 
 /*
diff --git a/src/nvim/testdir/test_execute_func.vim b/src/nvim/testdir/test_execute_func.vim
index 2cb6d73407..bb601e19ac 100644
--- a/src/nvim/testdir/test_execute_func.vim
+++ b/src/nvim/testdir/test_execute_func.vim
@@ -147,3 +147,15 @@ func Test_win_execute_other_tab()
   tabclose
   unlet xyz
 endfunc
+
+func Test_win_execute_visual_redraw()
+  call setline(1, ['a', 'b', 'c'])
+  new
+  wincmd p
+  call feedkeys("G\<C-V>", 'txn')
+  call win_execute(winnr('#')->win_getid(), 'redraw')
+  bwipe!
+  bwipe!
+endfunc
+
+" vim: shiftwidth=2 sts=2 expandtab
diff --git a/src/nvim/window.c b/src/nvim/window.c
index 8e44fd5014..6996a93928 100644
--- a/src/nvim/window.c
+++ b/src/nvim/window.c
@@ -577,18 +577,19 @@ static void cmd_with_count(char *cmd, char_u *bufp, size_t bufsize, int64_t Pren
 
 void win_set_buf(Window window, Buffer buffer, bool noautocmd, Error *err)
 {
-  win_T *win = find_window_by_handle(window, err), *save_curwin = curwin;
+  win_T *win = find_window_by_handle(window, err);
   buf_T *buf = find_buffer_by_handle(buffer, err);
-  tabpage_T *tab = win_find_tabpage(win), *save_curtab = curtab;
+  tabpage_T *tab = win_find_tabpage(win);
 
   if (!win || !buf) {
     return;
   }
-
   if (noautocmd) {
     block_autocmds();
   }
-  if (switch_win_noblock(&save_curwin, &save_curtab, win, tab, false) == FAIL) {
+
+  switchwin_T switchwin;
+  if (switch_win_noblock(&switchwin, win, tab, false) == FAIL) {
     api_set_error(err,
                   kErrorTypeException,
                   "Failed to switch to window %d",
@@ -608,7 +609,7 @@ void win_set_buf(Window window, Buffer buffer, bool noautocmd, Error *err)
   // So do it now.
   validate_cursor();
 
-  restore_win_noblock(save_curwin, save_curtab, false);
+  restore_win_noblock(&switchwin, false);
   if (noautocmd) {
     unblock_autocmds();
   }
@@ -6631,20 +6632,27 @@ static win_T *get_snapshot_focus(int idx)
 ///                    triggered, another tabpage access is limited.
 ///
 /// @return FAIL if switching to "win" failed.
-int switch_win(win_T **save_curwin, tabpage_T **save_curtab, win_T *win, tabpage_T *tp,
-               bool no_display)
+int switch_win(switchwin_T *switchwin, win_T *win, tabpage_T *tp, bool no_display)
 {
   block_autocmds();
-  return switch_win_noblock(save_curwin, save_curtab, win, tp, no_display);
+  return switch_win_noblock(switchwin, win, tp, no_display);
 }
 
 // As switch_win() but without blocking autocommands.
-int switch_win_noblock(win_T **save_curwin, tabpage_T **save_curtab, win_T *win, tabpage_T *tp,
-                       bool no_display)
+int switch_win_noblock(switchwin_T *switchwin, win_T *win, tabpage_T *tp, bool no_display)
 {
-  *save_curwin = curwin;
+  memset(switchwin, 0, sizeof(switchwin_T));
+  switchwin->sw_curwin = curwin;
+  if (win == curwin) {
+    switchwin->sw_same_win = true;
+  } else {
+    // Disable Visual selection, because redrawing may fail.
+    switchwin->sw_visual_active = VIsual_active;
+    VIsual_active = false;
+  }
+
   if (tp != NULL) {
-    *save_curtab = curtab;
+    switchwin->sw_curtab = curtab;
     if (no_display) {
       curtab->tp_firstwin = firstwin;
       curtab->tp_lastwin = lastwin;
@@ -6666,28 +6674,33 @@ int switch_win_noblock(win_T **save_curwin, tabpage_T **save_curtab, win_T *win,
 // Restore current tabpage and window saved by switch_win(), if still valid.
 // When "no_display" is true the display won't be affected, no redraw is
 // triggered.
-void restore_win(win_T *save_curwin, tabpage_T *save_curtab, bool no_display)
+void restore_win(switchwin_T *switchwin, bool no_display)
 {
-  restore_win_noblock(save_curwin, save_curtab, no_display);
+  restore_win_noblock(switchwin, no_display);
   unblock_autocmds();
 }
 
 // As restore_win() but without unblocking autocommands.
-void restore_win_noblock(win_T *save_curwin, tabpage_T *save_curtab, bool no_display)
+void restore_win_noblock(switchwin_T *switchwin, bool no_display)
 {
-  if (save_curtab != NULL && valid_tabpage(save_curtab)) {
+  if (switchwin->sw_curtab != NULL && valid_tabpage(switchwin->sw_curtab)) {
     if (no_display) {
       curtab->tp_firstwin = firstwin;
       curtab->tp_lastwin = lastwin;
-      curtab = save_curtab;
+      curtab = switchwin->sw_curtab;
       firstwin = curtab->tp_firstwin;
       lastwin = curtab->tp_lastwin;
     } else {
-      goto_tabpage_tp(save_curtab, false, false);
+      goto_tabpage_tp(switchwin->sw_curtab, false, false);
     }
   }
-  if (win_valid(save_curwin)) {
-    curwin = save_curwin;
+
+  if (!switchwin->sw_same_win) {
+    VIsual_active = switchwin->sw_visual_active;
+  }
+
+  if (win_valid(switchwin->sw_curwin)) {
+    curwin = switchwin->sw_curwin;
     curbuf = curwin->w_buffer;
   }
   // If called by win_execute() and executing the command changed the
diff --git a/src/nvim/window.h b/src/nvim/window.h
index 7e465a9f08..925cc68b60 100644
--- a/src/nvim/window.h
+++ b/src/nvim/window.h
@@ -32,6 +32,14 @@
 #define MIN_COLUMNS     12      // minimal columns for screen
 #define MIN_LINES       2       // minimal lines for screen
 
+/// Structure used by switch_win() to pass values to restore_win()
+typedef struct {
+  win_T *sw_curwin;
+  tabpage_T *sw_curtab;
+  bool sw_same_win;  ///< VIsual_active was not reset
+  bool sw_visual_active;
+} switchwin_T;
+
 #ifdef INCLUDE_GENERATED_DECLARATIONS
 # include "window.h.generated.h"
 #endif