patch 7.4.1654

Problem:    Crash when using expand('%:S') in a buffer without a name.
Solution:   Don't set a NUL. (James McCoy, closes #714)

Author: brammool

src/eval.c

@@ -26439,9 +26439,11 @@ modify_fname(
     {
 	/* vim_strsave_shellescape() needs a NUL terminated string. */
 	c = (*fnamep)[*fnamelen];
-	(*fnamep)[*fnamelen] = NUL;
+	if (c != NUL)
+	    (*fnamep)[*fnamelen] = NUL;
 	p = vim_strsave_shellescape(*fnamep, FALSE, FALSE);
-	(*fnamep)[*fnamelen] = c;
+	if (c != NUL)
+	    (*fnamep)[*fnamelen] = c;
 	if (p == NULL)
 	    return -1;
 	vim_free(*bufp);

src/testdir/test_fnamemodify.vim

@@ -41,3 +41,9 @@ func Test_fnamemodify()
   call assert_equal("'abc\\\ndef'",  fnamemodify("abc\ndef", ':S'))
   set shell&
 endfunc
+
+func Test_expand()
+  new
+  call assert_equal("",  expand('%:S'))
+  quit
+endfunc

src/version.c

@@ -748,6 +748,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1654,
 /**/
     1653,
 /**/