Index: subversion/libsvn_subr/svn_string.c
===================================================================
--- subversion/libsvn_subr/svn_string.c	(revision 6178)
+++ subversion/libsvn_subr/svn_string.c	(working copy)
@@ -317,11 +317,15 @@
 void
 svn_stringbuf_set (svn_stringbuf_t *str, const char *value)
 {
-  apr_size_t amt = strlen (value);
+  if (value) {
+    apr_size_t amt = strlen (value);
 
-  svn_stringbuf_ensure (str, amt + 1);
-  memcpy (str->data, value, amt + 1);
-  str->len = amt;
+    svn_stringbuf_ensure (str, amt + 1);
+    memcpy (str->data, value, amt + 1);
+    str->len = amt;
+  } else {
+	svn_stringbuf_setempty(str);
+  }
 }
 
 void