vim-patch:8.2.1910: reading past the end of the command line

Problem:    Reading past the end of the command line.
Solution:   Check for NUL. (closes vim/vim#7204)
caf73dcfad

Cherry-pick undo_cmdmod() from patch 8.2.1137.

N/A patches for version.c:

vim-patch:8.1.2050: popup window test fails in some configurations

Problem:    Popup window test fails in some configurations. (James McCoy)
Solution:   Clear the command line.
7e0f462db5

vim-patch:8.2.0913: code for resetting v:register is duplicated

Problem:    Code for resetting v:register is duplicated.
Solution:   Add reset_reg_var().
439c036ed0

reset_reg_var() is not ported.
Use set_reg_var(get_default_register_name()) instead.

vim-patch:8.2.1913: GTK GUI: rounding for the cell height is too strict

Problem:    GTK GUI: rounding for the cell height is too strict.
Solution:   Round up above 15/16 of a pixel. (closes vim/vim#7203)
70cf45810c

vim-patch:8.2.1922: Win32: scrolling problems when part of window is off-screen

Problem:    Win32: scrolling doesn't work properly when part of window is
            off-screen.
Solution:   Fall back to GDI scrolling if part of the window is off-screen.
            Handle multi-monitor setup better. (Ken Takata, closes vim/vim#7219)
185577e47e

src/nvim/ex_docmd.c

@@ -1251,7 +1251,7 @@ static char_u * do_one_cmd(char_u **cmdlinep,
   char_u              *errormsg = NULL;  // error message
   char_u              *after_modifier = NULL;
   exarg_T ea;
-  int save_msg_scroll = msg_scroll;
+  const int save_msg_scroll = msg_scroll;
   cmdmod_T save_cmdmod;
   const int save_reg_executing = reg_executing;
   char_u              *cmd;
@@ -2003,34 +2003,10 @@ doend:
       ? cmdnames[(int)ea.cmdidx].cmd_name
       : (char_u *)NULL);
 
-  if (ea.verbose_save >= 0) {
-    p_verbose = ea.verbose_save;
-  }
-  free_cmdmod();
-
+  undo_cmdmod(&ea, save_msg_scroll);
   cmdmod = save_cmdmod;
   reg_executing = save_reg_executing;
 
-  if (ea.save_msg_silent != -1) {
-    // messages could be enabled for a serious error, need to check if the
-    // counters don't become negative
-    if (!did_emsg || msg_silent > ea.save_msg_silent) {
-      msg_silent = ea.save_msg_silent;
-    }
-    emsg_silent -= ea.did_esilent;
-    if (emsg_silent < 0) {
-      emsg_silent = 0;
-    }
-    // Restore msg_scroll, it's set by file I/O commands, even when no
-    // message is actually displayed.
-    msg_scroll = save_msg_scroll;
-
-    /* "silent reg" or "silent echo x" inside "redir" leaves msg_col
-     * somewhere in the line.  Put it back in the first column. */
-    if (redirecting())
-      msg_col = 0;
-  }
-
   if (ea.did_sandbox) {
     sandbox--;
   }
@@ -2298,9 +2274,14 @@ int parse_command_modifiers(exarg_T *eap, char_u **errormsg, bool skip_only)
   return OK;
 }
 
-// Free contents of "cmdmod".
-static void free_cmdmod(void)
+// Undo and free contents of "cmdmod".
+static void undo_cmdmod(const exarg_T *eap, int save_msg_scroll)
+  FUNC_ATTR_NONNULL_ALL
 {
+  if (eap->verbose_save >= 0) {
+    p_verbose = eap->verbose_save;
+  }
+
   if (cmdmod.save_ei != NULL) {
     /* Restore 'eventignore' to the value before ":noautocmd". */
     set_string_option_direct((char_u *)"ei", -1, cmdmod.save_ei,
@@ -2308,8 +2289,27 @@ static void free_cmdmod(void)
     free_string_option(cmdmod.save_ei);
   }
 
-  if (cmdmod.filter_regmatch.regprog != NULL) {
-    vim_regfree(cmdmod.filter_regmatch.regprog);
+  vim_regfree(cmdmod.filter_regmatch.regprog);
+
+  if (eap->save_msg_silent != -1) {
+    // messages could be enabled for a serious error, need to check if the
+    // counters don't become negative
+    if (!did_emsg || msg_silent > eap->save_msg_silent) {
+      msg_silent = eap->save_msg_silent;
+    }
+    emsg_silent -= eap->did_esilent;
+    if (emsg_silent < 0) {
+      emsg_silent = 0;
+    }
+    // Restore msg_scroll, it's set by file I/O commands, even when no
+    // message is actually displayed.
+    msg_scroll = save_msg_scroll;
+
+    // "silent reg" or "silent echo x" inside "redir" leaves msg_col
+    // somewhere in the line.  Put it back in the first column.
+    if (redirecting()) {
+      msg_col = 0;
+    }
   }
 }
 
@@ -4446,6 +4446,9 @@ void separate_nextcmd(exarg_T *eap)
     else if (p[0] == '`' && p[1] == '=' && (eap->argt & XFILE)) {
       p += 2;
       (void)skip_expr(&p);
+      if (*p == NUL) {  // stop at NUL after CTRL-V
+        break;
+      }
     }
     /* Check for '"': start of comment or '|': next command */
     /* :@" does not start a comment!

src/nvim/testdir/test_edit.vim

@@ -1587,4 +1587,11 @@ func Test_edit_browse()
   bwipe!
 endfunc
 
+func Test_read_invalid()
+  " set encoding=latin1
+  " This was not properly checking for going past the end.
+  call assert_fails('r`=', 'E484')
+  set encoding=utf-8
+endfunc
+
 " vim: shiftwidth=2 sts=2 expandtab