patch 8.2.4074: going over the end of NameBuff

Problem:    Going over the end of NameBuff.
Solution:   Check length when appending a space.

src/drawscreen.c

@@ -462,12 +462,13 @@ win_redr_status(win_T *wp, int ignore_pum UNUSED)
 	p = NameBuff;
 	len = (int)STRLEN(p);
 
-	if (bt_help(wp->w_buffer)
+	if ((bt_help(wp->w_buffer)
 #ifdef FEAT_QUICKFIX
-		|| wp->w_p_pvw
+		    || wp->w_p_pvw
 #endif
-		|| bufIsChanged(wp->w_buffer)
-		|| wp->w_buffer->b_p_ro)
+		    || bufIsChanged(wp->w_buffer)
+		    || wp->w_buffer->b_p_ro)
+		&& len < MAXPATHL - 1)
 	    *(p + len++) = ' ';
 	if (bt_help(wp->w_buffer))
 	{

src/testdir/test_edit.vim

@@ -2103,5 +2103,20 @@ func Test_edit_CTRL_hat()
   bwipe!
 endfunc
 
+" Weird long file name was going over the end of NameBuff
+func Test_edit_overlong_file_name()
+  CheckUnix
+
+  file 0000000000000000000000000000
+  file %%%%%%%%%%%%%%%%%%%%%%%%%%
+  file %%%%%%
+  set readonly
+  set ls=2 
+
+  redraw!
+  set noreadonly ls&
+  bwipe!
+endfunc
+
 
 " vim: shiftwidth=2 sts=2 expandtab

src/userfunc.c

@@ -1674,12 +1674,10 @@ deref_func_name(
     void
 emsg_funcname(char *ermsg, char_u *name)
 {
-    char_u	*p;
+    char_u	*p = name;
 
-    if (*name == K_SPECIAL)
+    if (name[0] == K_SPECIAL && name[1] != NUL && name[2] != NUL)
 	p = concat_str((char_u *)"<SNR>", name + 3);
-    else
-	p = name;
     semsg(_(ermsg), p);
     if (p != name)
 	vim_free(p);
@@ -4154,6 +4152,8 @@ define_function(exarg_T *eap, char_u *name_arg, garray_T *lines_to_free)
 	    else
 		eap->skip = TRUE;
 	}
+	if (name == NULL)
+	    goto ret_free;  // out of memory
 
 	// For "export def FuncName()" in an autoload script the function name
 	// is stored with the legacy autoload name "dir#script#FuncName" so

src/version.c

@@ -750,6 +750,10 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    4074,
+/**/
+    4073,
 /**/
     4072,
 /**/