Add null-field checks to shape field mappers (#71999)

#71696 introduced a regression to the various shape field mappers,
where they would no longer handle null values. This commit fixes
that regression and adds a testNullValues method to MapperTestCase
to ensure that all field mappers correctly handle nulls.

Fixes #71874

Author: romseygeek

modules/mapper-extras/src/test/java/org/elasticsearch/index/mapper/RankFeaturesFieldMapperTests.java

@@ -141,4 +141,9 @@ protected Object generateRandomInputValue(MappedFieldType ft) {
         assumeFalse("Test implemented in a follow up", true);
         return null;
     }
+
+    @Override
+    protected boolean allowsNullValues() {
+        return false;       // TODO should this allow null values?
+    }
 }

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

@@ -198,6 +198,9 @@ protected void checkIncomingMergeType(FieldMapper mergeWith) {
 
     @Override
     protected void index(ParseContext context, Geometry geometry) throws IOException {
+        if (geometry == null) {
+            return;
+        }
         context.doc().addAll(indexer.indexShape(geometry));
         createFieldNamesField(context);
     }

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

@@ -476,6 +476,9 @@ String strategy() {
 
     @Override
     protected void index(ParseContext context, ShapeBuilder<?, ?, ?> shapeBuilder) throws IOException {
+        if (shapeBuilder == null) {
+            return;
+        }
         Shape shape = shapeBuilder.buildS4J();
         if (fieldType().pointsOnly()) {
             // index configured for pointsOnly

test/framework/src/main/java/org/elasticsearch/index/mapper/MapperTestCase.java

@@ -691,4 +691,19 @@ private BiFunction<MappedFieldType, Supplier<SearchLookup>, IndexFieldData<?>> f
             .fielddataBuilder("test", lookupSource)
             .build(new IndexFieldDataCache.None(), new NoneCircuitBreakerService());
     }
+
+    public final void testNullInput() throws Exception {
+        DocumentMapper mapper = createDocumentMapper(fieldMapping(this::minimalMapping));
+        if (allowsNullValues()) {
+            ParsedDocument doc = mapper.parse(source(b -> b.nullField("field")));
+            assertThat(doc.docs().get(0).getFields("field").length, equalTo(0));
+            assertThat(doc.docs().get(0).getFields("_field_names").length, equalTo(0));
+        } else {
+            expectThrows(MapperParsingException.class, () -> mapper.parse(source(b -> b.nullField("field"))));
+        }
+    }
+
+    protected boolean allowsNullValues() {
+        return true;
+    }
 }

x-pack/plugin/mapper-constant-keyword/src/internalClusterTest/java/org/elasticsearch/xpack/constantkeyword/mapper/ConstantKeywordFieldMapperTests.java

@@ -172,4 +172,9 @@ protected String generateRandomInputValue(MappedFieldType ft) {
     protected void randomFetchTestFieldConfig(XContentBuilder b) throws IOException {
         b.field("type", "constant_keyword").field("value", randomAlphaOfLengthBetween(1, 10));
     }
+
+    @Override
+    protected boolean allowsNullValues() {
+        return false;   // null is an error for constant keyword
+    }
 }

x-pack/plugin/spatial/src/main/java/org/elasticsearch/xpack/spatial/index/mapper/GeoShapeWithDocValuesFieldMapper.java

@@ -207,6 +207,9 @@ public GeoShapeWithDocValuesFieldMapper(String simpleName, MappedFieldType mappe
 
     @Override
     protected void index(ParseContext context, Geometry geometry) throws IOException {
+        if (geometry == null) {
+            return;
+        }
         List<IndexableField> fields = indexer.indexShape(geometry);
         if (fieldType().isSearchable()) {
             context.doc().addAll(fields);

x-pack/plugin/spatial/src/main/java/org/elasticsearch/xpack/spatial/index/mapper/ShapeFieldMapper.java

@@ -137,6 +137,9 @@ public ShapeFieldMapper(String simpleName, MappedFieldType mappedFieldType,
 
     @Override
     protected void index(ParseContext context, Geometry geometry) throws IOException {
+        if (geometry == null) {
+            return;
+        }
         context.doc().addAll(indexer.indexShape(geometry));
         createFieldNamesField(context);
     }

x-pack/plugin/vectors/src/test/java/org/elasticsearch/xpack/vectors/mapper/DenseVectorFieldMapperTests.java

@@ -160,4 +160,9 @@ protected Object generateRandomInputValue(MappedFieldType ft) {
         assumeFalse("Test implemented in a follow up", true);
         return null;
     }
+
+    @Override
+    protected boolean allowsNullValues() {
+        return false;       // TODO should this allow null values?
+    }
 }