Iterate over result list in reverse order to avoid stale

array indexes when removing array elements.

2 files changed, 22 insertions, 2 deletions

diff --git a/document/src/main/java/com/yahoo/document/fieldpathupdate/FieldPathUpdate.java b/document/src/main/java/com/yahoo/document/fieldpathupdate/FieldPathUpdate.java
index 82dea23bb85..29c876b85fe 100644
--- a/document/src/main/java/com/yahoo/document/fieldpathupdate/FieldPathUpdate.java
+++ b/document/src/main/java/com/yahoo/document/fieldpathupdate/FieldPathUpdate.java
@@ -12,6 +12,7 @@ import com.yahoo.document.select.ResultList;
 import com.yahoo.document.select.parser.ParseException;
 import com.yahoo.document.serialization.DocumentUpdateReader;
 import com.yahoo.document.serialization.VespaDocumentSerializerHead;
+import java.util.ListIterator;
 
 /**
  * @author Thomas Gundersen
@@ -115,8 +116,9 @@ public abstract class FieldPathUpdate {
             doc.iterateNested(fieldPath, 0, handler);
         } else {
             ResultList results = selector.getMatchingResultList(new DocumentPut(doc));
-
-            for (ResultList.ResultPair rp : results.getResults()) {
+            ListIterator<ResultList.ResultPair> resultIter = results.getResults().listIterator(results.getResults().size());
+            while (resultIter.hasPrevious()) {
+                ResultList.ResultPair rp = resultIter.previous();
                 if (rp.getResult() == Result.TRUE) {
                     FieldPathIteratorHandler handler = getIteratorHandler(doc);
                     handler.getVariables().clear();
diff --git a/document/src/test/java/com/yahoo/document/DocumentPathUpdateTestCase.java b/document/src/test/java/com/yahoo/document/DocumentPathUpdateTestCase.java
index a0c891a3f30..ce55a5a501c 100755
--- a/document/src/test/java/com/yahoo/document/DocumentPathUpdateTestCase.java
+++ b/document/src/test/java/com/yahoo/document/DocumentPathUpdateTestCase.java
@@ -103,6 +103,24 @@ public class DocumentPathUpdateTestCase {
     }
 
     @Test
+    public void testApplyRemoveMultiList2() {
+        Document doc = new Document(docMan.getDocumentType("foobar"), new DocumentId("doc:something:foooo"));
+        assertNull(doc.getFieldValue("strarray"));
+        Array<StringFieldValue> strArray = new Array<>(doc.getField("strarray").getDataType());
+        strArray.add(new StringFieldValue("remove val 0 and 1"));
+        strArray.add(new StringFieldValue("remove val 0 and 1"));
+        strArray.add(new StringFieldValue("hello hello"));
+        doc.setFieldValue("strarray", strArray);
+        assertNotNull(doc.getFieldValue("strarray"));
+        DocumentUpdate docUp = new DocumentUpdate(docType, new DocumentId("doc:foo:bar"));
+        docUp.addFieldPathUpdate(new RemoveFieldPathUpdate(doc.getDataType(), "strarray[$x]", "foobar.strarray[$x] == \"remove val 0 and 1\""));
+        docUp.applyTo(doc);
+        assertEquals(1, ((List) doc.getFieldValue("strarray")).size());
+        List docList = (List) doc.getFieldValue("strarray");
+        assertEquals(new StringFieldValue("hello hello"), docList.get(0));
+    }
+
+    @Test
     public void testApplyRemoveEntireListField() {
         Document doc = new Document(docMan.getDocumentType("foobar"), new DocumentId("doc:something:foooo"));
         assertNull(doc.getFieldValue("strarray"));