Make LowerBound nullable

Author: schmidt-sebastian

firebase-firestore/src/main/java/com/google/firebase/firestore/local/SQLiteIndexManager.java

@@ -208,7 +208,9 @@ public Set<DocumentKey> getDocumentsMatchingTarget(Target target) {
     @Nullable FieldIndex fieldIndex = getMatchingIndex(target);
     if (fieldIndex == null) return null;
 
+    // Can this be an empty list?
     @Nullable List<Value> arrayValues = target.getArrayValues(fieldIndex);
+    // Can this be non-nullable again?
     @Nullable Bound lowerBound = target.getLowerBound(fieldIndex);
     @Nullable Bound upperBound = target.getUpperBound(fieldIndex);
 
@@ -224,9 +226,9 @@ public Set<DocumentKey> getDocumentsMatchingTarget(Target target) {
     }
 
     Object[] lowerBoundValues = encodeDirectionalBound(fieldIndex, target, lowerBound);
-    String lowerBoundOp = lowerBound != null ? (lowerBound.isInclusive() ? ">=" : ">") : null;
+    String lowerBoundOp = lowerBound != null && lowerBound.isInclusive() ? ">=" : ">";
     Object[] upperBoundValues = encodeDirectionalBound(fieldIndex, target, upperBound);
-    String upperBoundOp = upperBound != null ? (upperBound.isInclusive() ? "<=" : "<") : null;
+    String upperBoundOp = upperBound != null && upperBound.isInclusive() ? "<=" : "<";
 
     SQLitePersistence.Query query =
         generateQuery(
@@ -252,9 +254,9 @@ private SQLitePersistence.Query generateQuery(
       int indexId,
       @Nullable List<Value> arrayValues,
       @Nullable Object[] lowerBounds,
-      @Nullable String lowerBoundOp,
+      String lowerBoundOp,
       @Nullable Object[] upperBounds,
-      @Nullable String upperBoundOp) {
+      String upperBoundOp) {
     StringBuilder statement = new StringBuilder();
     statement.append(
         "SELECT document_name, directional_value FROM index_entries WHERE index_id = ? ");