29e50f56b4a784d2c37d48a9361d02e70638375e
braney
  Wed Mar 1 12:14:41 2017 -0800
add an assert to make sure we catch a potential trashed data situation #18950

diff --git src/hg/hgTracks/bigBedTrack.c src/hg/hgTracks/bigBedTrack.c
index 869b6d0..ccb1c0e 100644
--- src/hg/hgTracks/bigBedTrack.c
+++ src/hg/hgTracks/bigBedTrack.c
@@ -139,30 +139,31 @@
     if (!firstTime)
         dyStringAppend(dy, labelSeparator);
 
     switch(labelInt->val)
         {
         case 0:
             dyStringAppend(dy, chromName);
             break;
         case 1:
             dyStringPrintf(dy, "%d", bb->start);
             break;
         case 2:
             dyStringPrintf(dy, "%d", bb->end);
             break;
         default:
+            assert(bb->rest != NULL);
             dyStringPrintf(dy, "%s", restFields[labelInt->val - 3]);
             break;
         }
     firstTime = FALSE;
     }
 return dyStringCannibalize(&dy);
 }
 
 void bigBedAddLinkedFeaturesFromExt(struct track *track,
 	char *chrom, int start, int end, int scoreMin, int scoreMax, boolean useItemRgb,
 	int fieldCount, struct linkedFeatures **pLfList, int maxItems)
 /* Read in items in chrom:start-end from bigBed file named in track->bbiFileName, convert
  * them to linkedFeatures, and add to head of list. */
 {
 struct lm *lm = lmInit(0);