Ensure that empty TXT records always renders as ""

nresare · nresare · commit 43ad7806eb76 · 2022-07-24T21:05:38.000+01:00
Instantiating an empty TXT record using Record.fromString() would previously render as a TXT without the empty string. Closes #254
diff --git a/src/main/java/org/xbill/DNS/TXTBase.java b/src/main/java/org/xbill/DNS/TXTBase.java
@@ -73,6 +73,10 @@ protected void rdataFromString(Tokenizer st, Name origin) throws IOException {
   /** converts to a String */
   @Override
   protected String rrToString() {
+    if (strings.isEmpty()) {
+      // always return at least an empty quoted String
+      return "\"\"";
+    }
     StringBuilder sb = new StringBuilder();
     Iterator<byte[]> it = strings.iterator();
     while (it.hasNext()) {
diff --git a/src/test/java/org/xbill/DNS/RecordTest.java b/src/test/java/org/xbill/DNS/RecordTest.java
@@ -912,4 +912,12 @@ void testSerializable() throws IOException {
       }
     }
   }
+
+  // https://github.com/dnsjava/dnsjava/issues/254
+  @Test
+  void testEmptyTXTSerialization() throws IOException {
+    Name recordName = Name.fromString("name.name.");
+    Record r = Record.fromString(recordName, Type.TXT, DClass.IN, 0, "", recordName);
+    assertEquals("name.name.\t\t0\tIN\tTXT\t\"\"", r.toString());
+  }
 }

Original file line number	Diff line number	Diff line change
`@@ -912,4 +912,12 @@ void testSerializable() throws IOException {`
`912`	`912`	`}`
`913`	`913`	`}`
`914`	`914`	`}`
	`915`	`+`
	`916`	`+ // https://github.com/dnsjava/dnsjava/issues/254`
	`917`	`+ @Test`
	`918`	`+ void testEmptyTXTSerialization() throws IOException {`
	`919`	`+ Name recordName = Name.fromString("name.name.");`
	`920`	`+ Record r = Record.fromString(recordName, Type.TXT, DClass.IN, 0, "", recordName);`
	`921`	`+ assertEquals("name.name.\t\t0\tIN\tTXT\t\"\"", r.toString());`
	`922`	`+ }`
`915`	`923`	`}`