1231f270e5da6f5a817d887247b20e8f598b85d4
braney
  Fri Apr 26 10:03:24 2019 -0700
bigBed text filters with an empty string should match everything

diff --git src/hg/hgTracks/bigBedTrack.c src/hg/hgTracks/bigBedTrack.c
index 9ccd29a..ee39d11 100644
--- src/hg/hgTracks/bigBedTrack.c
+++ src/hg/hgTracks/bigBedTrack.c
@@ -125,30 +125,33 @@
             ret->value1 = min;
             ret->value2 = max;
             }
         }
     }
 return ret;
 }
 
 struct bigBedFilter *bigBedMakeFilterText(struct cart *cart, struct bbiFile *bbi, struct trackDb *tdb, char *filterName, char *field)
 /* Add a bigBed filter using a trackDb filterText statement. */
 {
 struct bigBedFilter *filter;
 char *setting = trackDbSettingClosestToHome(tdb, filterName);
 char *value = cartUsualStringClosestToHome(cart, tdb, FALSE, filterName, setting);
 
+if (isEmpty(value)) 
+    return NULL;
+
 char filterType[4096];
 safef(filterType, sizeof filterType, "%s%s", field, FILTER_TYPE_NAME);
 char *typeValue = cartOrTdbString(cart, tdb, filterType, FILTERTEXT_WILDCARD);
 
 AllocVar(filter);
 filter->fieldNum =  bbExtraFieldIndex(bbi, field) + 3;
 
 if (sameString(typeValue, FILTERTEXT_REGEXP) )
     {
     filter->comparisonType = COMPARE_REGEXP;
     regcomp(&filter->regEx, value, REG_NOSUB);
     }
 else
     {
     filter->comparisonType = COMPARE_WILDCARD;