diff --git a/CHANGES b/CHANGES
index 0e86989..c7c5bbb 100644
--- a/CHANGES
+++ b/CHANGES
@@ -1,8 +1,12 @@
-0.49 2014-11-12
+0.49 2014-11-14
         - [bugfix] Rewrite works in repeating expansions (margaretha)
 	- [feature] Clean timeout with parameter support (diewald)
 	- [workaround] Support unknown overlap frame, if frames are known (diewald)
 	- [bugfix] Class payload fixed in SpanRepetitions (margaretha)
+	- [bugfix] #179 Expansion bug fixed (margaretha)
+	- [bugfix] Corrected small bug where null warnings where
+	  returned in JSON (diewald)
+	- [cleanup] Converted error to failure (diewald)
 
 0.48 2014-11-07
         - [feature] Retrieval of token lists (diewald)
diff --git a/src/main/java/de/ids_mannheim/korap/KorapQuery.java b/src/main/java/de/ids_mannheim/korap/KorapQuery.java
index 0233234..d07c100 100644
--- a/src/main/java/de/ids_mannheim/korap/KorapQuery.java
+++ b/src/main/java/de/ids_mannheim/korap/KorapQuery.java
@@ -716,11 +716,13 @@
         return this.warning;
     };
 
-    public void addWarning (String warning) {
+    public void addWarning (String msg) {
+	if (msg == null)
+	    return;
 	if (this.warning == null)
-	    this.warning = warning;
+	    this.warning = msg;
 	else
-	    this.warning += "; " + warning;
+	    this.warning += "; " + msg;
     };
 
     public void setWarning (String warning) {
diff --git a/src/main/java/de/ids_mannheim/korap/KorapResult.java b/src/main/java/de/ids_mannheim/korap/KorapResult.java
index 0db50aa..ab4389a 100644
--- a/src/main/java/de/ids_mannheim/korap/KorapResult.java
+++ b/src/main/java/de/ids_mannheim/korap/KorapResult.java
@@ -141,9 +141,11 @@
         return this.warning;
     }
 
-    public void addWarning (String warning) {
+    public void addWarning (String msg) {
+	if (msg == null)
+	    return;
 	if (this.warning == null)
-	    this.warning = warning;
+	    this.warning = msg;
 	else
 	    this.warning += "; " + warning;
     };
diff --git a/src/main/java/de/ids_mannheim/korap/KorapSearch.java b/src/main/java/de/ids_mannheim/korap/KorapSearch.java
index e8c0a6b..2d342b2 100644
--- a/src/main/java/de/ids_mannheim/korap/KorapSearch.java
+++ b/src/main/java/de/ids_mannheim/korap/KorapSearch.java
@@ -109,12 +109,13 @@
 	    };
 
 	    // Legacy code: Report warning coming from the request
-	    if (this.request.has("warning"))
+	    if (this.request.has("warning") && this.request.get("warning").asText().length() > 0)
 		this.addWarning(this.request.get("warning").asText());
 	    if (this.request.has("warnings")) {
 		JsonNode warnings = this.request.get("warnings");
 		for (JsonNode node : warnings)
-		    this.addWarning(node.asText());
+		    if (node.asText().length() > 0)
+			this.addWarning(node.asText());
 	    };
 	    // end of legacy code
 
@@ -215,11 +216,14 @@
 	return this.warning;
     };
 
-    public void addWarning (String warning) {
+    public void addWarning (String msg) {
+	if (msg == null)
+	    return;
+
 	if (this.warning == null)
-	    this.warning = warning;
+	    this.warning = msg;
 	else
-	    this.warning += "; " + warning;
+	    this.warning += "; " + msg;
     };
 
     public SpanQuery getQuery () {
diff --git a/src/test/java/de/ids_mannheim/korap/highlight/TestClass.java b/src/test/java/de/ids_mannheim/korap/highlight/TestClass.java
index bb1112f..8f59345 100644
--- a/src/test/java/de/ids_mannheim/korap/highlight/TestClass.java
+++ b/src/test/java/de/ids_mannheim/korap/highlight/TestClass.java
@@ -68,7 +68,7 @@
 		);
 		SpanQuery sq = sqwi.toQuery();
 		
-		System.out.println(sq.toString());
+		// System.out.println(sq.toString());
 		
 
 		ki = new KorapIndex();
@@ -78,11 +78,13 @@
 	    ki.commit();
 		kr = ki.search(sq, (short) 10);
 				
+		/*
 		for (KorapMatch km : kr.getMatches()){
 			System.out.println(km.getStartPos() +","+km.getEndPos()+" "
 					+km.getSnippetBrackets()
 			);
 		}
+		*/
 		assertEquals(495, kr.getTotalResults());
 		assertEquals(3, kr.getMatch(0).getStartPos());
 		assertEquals(5, kr.getMatch(0).getEndPos());
diff --git a/src/test/java/de/ids_mannheim/korap/index/TestWithinIndex.java b/src/test/java/de/ids_mannheim/korap/index/TestWithinIndex.java
index ee7f712..75ff3c9 100644
--- a/src/test/java/de/ids_mannheim/korap/index/TestWithinIndex.java
+++ b/src/test/java/de/ids_mannheim/korap/index/TestWithinIndex.java
@@ -1093,19 +1093,25 @@
 	ki.addDocFile(
 		      getClass().getResource("/wiki/PPP-02924.json.gz").getFile(),true);
 	ki.commit();
-	KorapResult kr = ki.search(sq, (short) 10);
+	try {
+	    KorapResult kr = ki.search(sq, (short) 10);
+	    assertEquals(2, kr.getTotalResults());
+	    assertEquals(0, kr.getMatch(0).getLocalDocID());
+	    assertEquals(76, kr.getMatch(0).getStartPos());
+	    assertEquals(93, kr.getMatch(0).getEndPos());
+	    assertEquals(1, kr.getMatch(0).getLocalDocID());
+	    assertEquals(237, kr.getMatch(1).getStartPos());
+	    assertEquals(252, kr.getMatch(1).getEndPos());
+	}
+
+	catch (Exception e) {
+	    fail("Nullpointer (known)");
+	};
 //		for (KorapMatch km : kr.getMatches()){		
 //			System.out.println(km.getStartPos() +","+km.getEndPos()+" "
 //				+km.getSnippetBrackets());
 //		}		
 	
-	assertEquals(2, kr.getTotalResults());
-	assertEquals(0, kr.getMatch(0).getLocalDocID());
-	assertEquals(76, kr.getMatch(0).getStartPos());
-	assertEquals(93, kr.getMatch(0).getEndPos());
-	assertEquals(1, kr.getMatch(0).getLocalDocID());
-	assertEquals(237, kr.getMatch(1).getStartPos());
-	assertEquals(252, kr.getMatch(1).getEndPos());
     }
 	
 	
diff --git a/src/test/java/de/ids_mannheim/korap/search/TestKorapResult.java b/src/test/java/de/ids_mannheim/korap/search/TestKorapResult.java
index 983d3eb..b353ee1 100644
--- a/src/test/java/de/ids_mannheim/korap/search/TestKorapResult.java
+++ b/src/test/java/de/ids_mannheim/korap/search/TestKorapResult.java
@@ -95,6 +95,35 @@
     };
 
     @Test
+    public void checkJSONResultWarningBug () throws Exception  {
+	KorapIndex ki = new KorapIndex();
+	FieldDocument fd = new FieldDocument();
+	fd.addString("ID", "doc-1");
+	fd.addString("UID", "1");
+	fd.addTV("tokens",
+		 "abab",
+		 "[(0-1)s:a|i:a|_0#0-1|-:t$<i>4]" +
+		 "[(1-2)s:b|i:b|_1#1-2]" +
+		 "[(2-3)s:a|i:c|_2#2-3]" +
+		 "[(3-4)s:b|i:a|_3#3-4]");
+	ki.addDoc(fd);
+	ki.commit();
+
+	String json = getString(getClass().getResource("/queries/bugs/optionality_warning.jsonld").getFile());
+	KorapSearch ks = new KorapSearch(json);
+
+	KorapResult kr = ks.run(ki);
+	assertEquals(2, kr.getTotalResults());
+
+	ObjectMapper mapper = new ObjectMapper();
+	JsonNode res = mapper.readTree(kr.toJSON());
+
+	assertEquals("Optionality of query is ignored", res.at("/warning").asText());
+
+    };
+
+
+    @Test
     public void checkJSONResultForJSONInput () throws Exception  {
 	KorapIndex ki = new KorapIndex();
 	FieldDocument fd = new FieldDocument();
diff --git a/src/test/java/de/ids_mannheim/korap/search/TestKorapSearch.java b/src/test/java/de/ids_mannheim/korap/search/TestKorapSearch.java
index 8765457..06908d7 100644
--- a/src/test/java/de/ids_mannheim/korap/search/TestKorapSearch.java
+++ b/src/test/java/de/ids_mannheim/korap/search/TestKorapSearch.java
@@ -1011,7 +1011,7 @@
 	        );
 	
 		kr = new KorapSearch(json).run(ki);
-		System.out.println(kr.getQuery());
+		// System.out.println(kr.getQuery());
 //		if (kr.getTotalResults() != 1)
 //		    fail("Expansion fails");
 	
diff --git a/src/test/resources/queries/bugs/optionality_warning.jsonld b/src/test/resources/queries/bugs/optionality_warning.jsonld
new file mode 100644
index 0000000..08b9df9
--- /dev/null
+++ b/src/test/resources/queries/bugs/optionality_warning.jsonld
@@ -0,0 +1,27 @@
+{
+  "@context" : "http://ids-mannheim.de/ns/KorAP/json-ld/v0.2/context.jsonld",
+  "query" : {
+    "@type" : "korap:group",
+    "boundary" : {
+      "@type" : "korap:boundary",
+      "max" : 1,
+      "min" : 0
+    },
+    "max" : 1,
+    "min" : 0,
+    "operands" : [
+      {
+        "@type" : "korap:token",
+        "wrap" : {
+          "@type" : "korap:term",
+          "foundry" : "opennlp",
+	  "layer" : "orth",
+          "key" : "a",
+          "match" : "match:eq"
+        }
+      }
+    ],
+    "operation" : "operation:repetition"
+  }
+}
+