Warn on badly-formed null values for date and IP field mappers (#62487)

In #57666 we changed when null_value was parsed for ip and date fields. Previously,
the null value was stored as a string, and parsed into a date or InetAddress whenever
a document containing a null value was encountered. Now, the values are parsed when
the mappings are built, which means that bad values are detected up front; if you try and
add a mapping with a badly-parsed ip or date for a null_value, the mapping will be
rejected.

This causes problems for upgrades in the case when you have a badly-formed null_value
in a pre-7.9 cluster. This commit fixes the upgrade case by changing the logic to only
logging a warning on the badly formed value, replicating the earlier behaviour.

Fixes #62363

Author: romseygeek

server/src/main/java/org/elasticsearch/index/mapper/DateFieldMapper.java

@@ -19,6 +19,7 @@
 
 package org.elasticsearch.index.mapper;
 
+import org.apache.logging.log4j.LogManager;
 import org.apache.lucene.document.FieldType;
 import org.apache.lucene.document.LongPoint;
 import org.apache.lucene.document.SortedNumericDocValuesField;
@@ -38,6 +39,7 @@
 import org.elasticsearch.common.Nullable;
 import org.elasticsearch.common.geo.ShapeRelation;
 import org.elasticsearch.common.joda.Joda;
+import org.elasticsearch.common.logging.DeprecationLogger;
 import org.elasticsearch.common.time.DateFormatter;
 import org.elasticsearch.common.time.DateFormatters;
 import org.elasticsearch.common.time.DateMathParser;
@@ -72,6 +74,8 @@
 /** A {@link FieldMapper} for dates. */
 public final class DateFieldMapper extends FieldMapper {
 
+    private static final DeprecationLogger DEPRECATION_LOGGER = new DeprecationLogger(LogManager.getLogger(DateFieldMapper.class));
+
     public static final String CONTENT_TYPE = "date";
     public static final String DATE_NANOS_CONTENT_TYPE = "date_nanos";
     public static final DateFormatter DEFAULT_DATE_TIME_FORMATTER = DateFormatter.forPattern("strict_date_optional_time||epoch_millis");
@@ -261,7 +265,9 @@ private Long parseNullValue(DateFieldType fieldType) {
                 return fieldType.parse(nullValue);
             }
             catch (Exception e) {
-                throw new MapperParsingException("Error parsing [null_value] on field [" + name() + "]: " + e.getMessage(), e);
+                DEPRECATION_LOGGER.deprecatedAndMaybeLog("date_field_null_value",
+                    "Error parsing [{}] as date in [null_value] on field [{}]; [null_value] will be ignored", nullValue, name);
+                return null;
             }
         }
 

server/src/main/java/org/elasticsearch/index/mapper/IpFieldMapper.java

@@ -19,6 +19,7 @@
 
 package org.elasticsearch.index.mapper;
 
+import org.apache.logging.log4j.LogManager;
 import org.apache.lucene.document.FieldType;
 import org.apache.lucene.document.InetAddressPoint;
 import org.apache.lucene.document.SortedSetDocValuesField;
@@ -35,6 +36,7 @@
 import org.elasticsearch.common.Explicit;
 import org.elasticsearch.common.Nullable;
 import org.elasticsearch.common.collect.Tuple;
+import org.elasticsearch.common.logging.DeprecationLogger;
 import org.elasticsearch.common.network.InetAddresses;
 import org.elasticsearch.common.xcontent.XContentBuilder;
 import org.elasticsearch.common.xcontent.support.XContentMapValues;
@@ -57,6 +59,8 @@
 /** A {@link FieldMapper} for ip addresses. */
 public class IpFieldMapper extends FieldMapper {
 
+    private static final DeprecationLogger DEPRECATION_LOGGER = new DeprecationLogger(LogManager.getLogger(IpFieldMapper.class));
+
     public static final String CONTENT_TYPE = "ip";
 
     public static class Defaults {
@@ -125,7 +129,14 @@ public Mapper.Builder<?> parse(String name, Map<String, Object> node, ParserCont
                     if (propNode == null) {
                         throw new MapperParsingException("Property [null_value] cannot be null.");
                     }
-                    builder.nullValue(InetAddresses.forString(propNode.toString()));
+                    try {
+                        builder.nullValue(InetAddresses.forString(propNode.toString()));
+                    }
+                    catch (Exception e) {
+                        DEPRECATION_LOGGER.deprecatedAndMaybeLog("ip_field_null_value",
+                            "Error parsing [{}] as IP in [null_value] on field [{}]; [null_value] will be ignored",
+                            propNode.toString(), name);
+                    }
                     iterator.remove();
                 } else if (propName.equals("ignore_malformed")) {
                     builder.ignoreMalformed(XContentMapValues.nodeBooleanValue(propNode, name + ".ignore_malformed"));

server/src/test/java/org/elasticsearch/index/mapper/DateFieldMapperTests.java

@@ -384,7 +384,7 @@ public void testNanosNullValue() throws IOException {
         assertFalse(dvField.fieldType().stored());
     }
 
-    public void testBadNullValue() throws IOException {
+    public void testBadFormat() throws IOException {
 
         String mapping = Strings.toString(XContentFactory.jsonBuilder().startObject()
             .startObject("type")
@@ -402,6 +402,28 @@ public void testBadNullValue() throws IOException {
             equalTo("Error parsing [format] on field [field]: No date pattern provided"));
     }
 
+    public void testBadNullValue() throws IOException {
+        String mapping = Strings.toString(XContentFactory.jsonBuilder().startObject()
+            .startObject("type")
+            .startObject("properties")
+            .startObject("field")
+            .field("type", "date")
+            .field("null_value", "foo")
+            .endObject()
+            .endObject()
+            .endObject().endObject());
+        DocumentMapper mapper = parser.parse("type", new CompressedXContent(mapping));
+        ParsedDocument doc = mapper.parse(new SourceToParse("test", "type", "1", BytesReference
+            .bytes(XContentFactory.jsonBuilder()
+                .startObject()
+                .nullField("field")
+                .endObject()),
+            XContentType.JSON));
+        IndexableField[] fields = doc.rootDoc().getFields("field");
+        assertEquals(0, fields.length);
+        assertWarnings("Error parsing [foo] as date in [null_value] on field [field]; [null_value] will be ignored");
+    }
+
     public void testTimeZoneParsing() throws Exception {
         final String timeZonePattern = "yyyy-MM-dd" + randomFrom("XXX", "[XXX]", "'['XXX']'");
 

server/src/test/java/org/elasticsearch/index/mapper/IpFieldMapperTests.java

@@ -268,6 +268,29 @@ public void testNullValue() throws IOException {
         assertEquals(DocValuesType.SORTED_SET, dvField.fieldType().docValuesType());
         assertEquals(new BytesRef(InetAddressPoint.encode(InetAddresses.forString("::1"))), dvField.binaryValue());
         assertFalse(dvField.fieldType().stored());
+
+        mapping = Strings.toString(XContentFactory.jsonBuilder().startObject()
+            .startObject("type")
+            .startObject("properties")
+            .startObject("field")
+            .field("type", "ip")
+            .field("null_value", ":1")
+            .endObject()
+            .endObject()
+            .endObject().endObject());
+
+        mapper = parser.parse("type", new CompressedXContent(mapping));
+
+        doc = mapper.parse(new SourceToParse("test", "type", "1", BytesReference
+            .bytes(XContentFactory.jsonBuilder()
+                .startObject()
+                .nullField("field")
+                .endObject()),
+            XContentType.JSON));
+        fields = doc.rootDoc().getFields("field");
+        assertEquals(0, fields.length);
+
+        assertWarnings("Error parsing [:1] as IP in [null_value] on field [field]; [null_value] will be ignored");
     }
 
     public void testSerializeDefaults() throws Exception {