776a6d9ae8ccc05256a1e1d25b2eaad6cfd3af12
braney
  Thu Feb 16 16:44:32 2017 -0800
fix problem with composites and the new label regime

diff --git src/hg/lib/trackDbCustom.c src/hg/lib/trackDbCustom.c
index ea12cf7..f220bf2 100644
--- src/hg/lib/trackDbCustom.c
+++ src/hg/lib/trackDbCustom.c
@@ -1277,35 +1277,35 @@
 struct tdbExtras *extras = tdb->tdbExtras;
 if (extras)
     return extras->membership;
 return tdbExtrasGet(tdb)->membership;
 }
 
 void tdbExtrasMembershipSet(struct trackDb *tdb,struct _membership *membership)
 // Sets the subtrack membership for later retrieval.
 {
 tdbExtrasGet(tdb)->membership = membership;
 }
 
 char *tdbBigFileName(struct sqlConnection *conn, struct trackDb *tdb)
 // Return file name associated with bigWig.  Do a freeMem on returned string when done.
 {
-char *ret;
+char *ret = NULL;
 char *fileName = trackDbSetting(tdb, "bigDataUrl"); // always takes precedence
 if (fileName != NULL)
     ret = cloneString(fileName);
-else
+else if (conn != NULL)
     {
     char query[256];
     sqlSafef(query, sizeof(query), "select fileName from %s", tdb->table);
     ret = sqlQuickString(conn, query);
     }
 
 // replace /gbdb if needed
 char *rewriteRet = hReplaceGbdb(ret);
 freeMem(ret);
 return rewriteRet;
 }
 
 static void rTdbTreeAllowPack(struct trackDb *tdb)
 // Force this tdb and all children to allow pack/squish
 {