SOLR-4036: field aliases in fl should not cause properties of target field to be used

git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/trunk@1408560 13f79535-47bb-0310-9956-ffa450edef68

solr/CHANGES.txt

@@ -179,6 +179,9 @@ Bug Fixes
 * SOLR-3989: SolrZkClient constructor dropped exception cause when throwing
   a new RuntimeException. (Colin Bartolome, yonik)
 
+* SOLR-4036: field aliases in fl should not cause properties of target field
+  to be used. (Martin Koch, yonik)
+
 
 Other Changes
 ----------------------

solr/core/src/java/org/apache/solr/response/JSONResponseWriter.java

@@ -23,6 +23,7 @@ import java.util.ArrayList;
 import java.util.Collection;
 import java.util.HashMap;
 import java.util.Iterator;
+import java.util.List;
 import java.util.Map;
 import java.util.Set;
 
@@ -342,18 +343,13 @@ class JSONWriter extends TextResponseWriter {
       writeKey(fname, true);
       Object val = doc.getFieldValue(fname);
 
-      if (val instanceof Collection) {
-        writeVal(fname, val);
+      // SolrDocument will now have multiValued fields represented as a Collection,
+      // even if only a single value is returned for this document.
+      if (val instanceof List) {
+        // shortcut this common case instead of going through writeVal again
+        writeArray(name,((Iterable)val).iterator());
       } else {
-        // if multivalued field, write single value as an array
-        SchemaField sf = schema.getFieldOrNull(fname);
-        if (sf != null && sf.multiValued()) {
-          writeArrayOpener(-1); // no trivial way to determine array size
-          writeVal(fname, val);
-          writeArrayCloser();
-        } else {
-          writeVal(fname, val);
-        }
+        writeVal(fname, val);
       }
     }
     

solr/core/src/test/org/apache/solr/search/TestPseudoReturnFields.java

@@ -59,6 +59,30 @@ public class TestPseudoReturnFields extends SolrTestCaseJ4 {
     assertU(commit());
   }
 
+  @Test
+  public void testMultiValued() throws Exception {
+    // the response writers used to consult isMultiValued on the field
+    // but this doesn't work when you alias a single valued field to
+    // a multi valued field (the field value is copied first, then
+    // if the type lookup is done again later, we get the wrong thing). SOLR-4036
+
+    assertJQ(req("q","id:42", "fl","val_ss:val_i, val2_ss:10")
+        ,"/response/docs==[{'val2_ss':10,'val_ss':1}]"
+    );
+
+    assertJQ(req("qt","/get", "id","42", "fl","val_ss:val_i, val2_ss:10")
+        ,"/doc=={'val2_ss':10,'val_ss':1}"
+    );
+
+    // also check real-time-get from transaction log
+    assertU(adoc("id", "42", "val_i", "1", "ssto", "X", "subject", "aaa"));
+
+    assertJQ(req("qt","/get", "id","42", "fl","val_ss:val_i, val2_ss:10")
+        ,"/doc=={'val2_ss':10,'val_ss':1}"
+    );
+
+  }
+  
   @Test
   public void testAllRealFields() throws Exception {