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 #7204)

Author: brammool

src/ex_docmd.c

@@ -2958,8 +2958,7 @@ undo_cmdmod(cmdmod_T *cmod)
 	cmod->cmod_save_ei = NULL;
     }
 
-    if (cmod->cmod_filter_regmatch.regprog != NULL)
-	vim_regfree(cmod->cmod_filter_regmatch.regprog);
+    vim_regfree(cmod->cmod_filter_regmatch.regprog);
 
     if (cmod->cmod_save_msg_silent > 0)
     {
@@ -4696,6 +4695,8 @@ separate_nextcmd(exarg_T *eap)
 	{
 	    p += 2;
 	    (void)skip_expr(&p, NULL);
+	    if (*p == NUL)		// stop at NUL after CTRL-V
+		break;
 	}
 #endif
 

src/testdir/test_edit.vim

@@ -1832,4 +1832,11 @@ 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

src/version.c

@@ -750,6 +750,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1910,
 /**/
     1909,
 /**/