23b804be0d6660580dd125f24e3e9a37bb59f8a8
braney
  Wed Sep 9 10:14:40 2015 -0700
fix crash in snake track controls refs #15994

diff --git src/hg/hgTrackUi/hgTrackUi.c src/hg/hgTrackUi/hgTrackUi.c
index 4a3fdc3..4534db1 100644
--- src/hg/hgTrackUi/hgTrackUi.c
+++ src/hg/hgTrackUi/hgTrackUi.c
@@ -2801,30 +2801,32 @@
     return;
 char *fileName = trackDbSetting(tdb, "bigDataUrl");
 char *errString;
 int handle = halOpenLOD(fileName, &errString);
 struct hal_species_t *speciesList, *sp;
 char *otherSpecies = trackDbSetting(tdb, "otherSpecies");
 extern char *database;
 
 speciesList = halGetPossibleCoalescenceLimits(handle, otherSpecies, 
     trackHubSkipHubName(database), &errString);
 
 int count = 0;
 for(sp=speciesList; sp; sp = sp->next)
     count++;
 
+if (count == 0)
+    return;
 char codeVarName[1024];
 safef(codeVarName, sizeof codeVarName, "%s.coalescent", tdb->track);
 char **ancestors;
 AllocArray(ancestors, count);
 count = 0;
 for(sp=speciesList; sp; sp = sp->next)
     {
     ancestors[count] = sp->name;
     count++;
     }
 char *coalescent = cartOptionalString(cart, codeVarName);
 printf("<B>Set Coalescent Ancestor to:</B>");
 cgiMakeDropListFull(codeVarName, ancestors, ancestors,
     count, coalescent, NULL);
 }