Merge r935526 from trunk to 1.3 branch. Fixes: AVRO-517.

git-svn-id: https://svn.apache.org/repos/asf/avro/branches/branch-1.3@951211 13f79535-47bb-0310-9956-ffa450edef68

CHANGES.txt

@@ -18,6 +18,8 @@ Avro 1.3.3 (Unreleased)
     AVRO-548. Python client should handle CLIENT handshake match status
     correctly. (hammer)
 
+    AVRO-517. Resolving Decoder fails in some cases. (thiru) 
+
 Avro 1.3.2 (31 March 2010)
 
   IMPROVEMENTS

lang/java/src/java/org/apache/avro/generic/GenericDatumReader.java

@@ -67,7 +67,10 @@ public D read(D reuse, Decoder in) throws IOException {
     if (resolver == null) {
       resolver = ResolvingDecoder.resolve(actual, expected);
     }
-    return (D) read(reuse, expected, new ResolvingDecoder(resolver, in));
+    ResolvingDecoder r = new ResolvingDecoder(resolver, in);
+    D result = (D) read(reuse, expected, r);
+    r.drain();
+    return result;
   }
 
   /** Called to read data.*/

lang/java/src/java/org/apache/avro/io/ResolvingDecoder.java

@@ -121,6 +121,25 @@ public final Schema.Field[] readFieldOrder() throws IOException {
     return ((Symbol.FieldOrderAction) parser.advance(Symbol.FIELD_ACTION)).
       fields;
   }
+
+  /**
+   * Consume any more data that has been written by the writer but not
+   * needed by the reader so that the the underlying decoder is in proper
+   * shape for the next record. This situation happens when, for example,
+   * the writer writes a record with two fields and the reader needs only the
+   * first field.
+   * 
+   * This function should be called after completely decoding an object but
+   * before next object can be decoded from the same underlying decoder
+   * either directly or through another resolving decoder. If the same resolving
+   * decoder is used for the next object as well, calling this method is
+   * optional; the state of this resolving decoder ensures that any leftover
+   * portions are consumed before the next object is decoded.
+   * @throws IOException
+   */
+  public final void drain() throws IOException {
+    parser.processImplicitActions();
+  }
 
   @Override
   public long readLong() throws IOException {

lang/java/src/test/java/org/apache/avro/io/TestResolvingIOResolving.java

@@ -79,6 +79,16 @@ public static Collection<Object[]> data3() {
   private static Object[][] dataForResolvingTests() {
     // The mnemonics are the same as {@link TestValidatingIO#testSchemas}
     return new Object[][] {
+        // Projection
+        { "{\"type\":\"record\",\"name\":\"r\",\"fields\":["
+          + "{\"name\":\"f1\", \"type\":\"string\"},"
+          + "{\"name\":\"f2\", \"type\":\"string\"},"
+          + "{\"name\":\"f3\", \"type\":\"int\"}]}", "S10S10IS10S10I",
+          new Object[] { "s1", "s2", 100, "t1", "t2", 200 },
+          "{\"type\":\"record\",\"name\":\"r\",\"fields\":["
+          + "{\"name\":\"f1\", \"type\":\"string\" },"
+          + "{\"name\":\"f2\", \"type\":\"string\"}]}", "RS10S10RS10S10",
+          new Object[] { "s1", "s2", "t1", "t2" } },
         // Reordered fields
         { "{\"type\":\"record\",\"name\":\"r\",\"fields\":["
           + "{\"name\":\"f1\", \"type\":\"int\"},"