Add extra round trip to aggs tests (backport of elastic#79638)

This tries to automatically detect problems seriealization aggregation
results by round tripping the results in our usual `AggregatorTestCase`.
It's "free" testing in that we already have the tests written and we'll
get round trip testing "on the side". But it's kind of sneaky because we
aren't *trying* to test serialization here. So they failures can be
surprising. But surprising test failures are better than bugs. At least
that is what I tell myself so I can sleep at night. Closes elastic#73680

server/src/main/java/org/elasticsearch/search/DocValueFormat.java

@@ -332,6 +332,26 @@ public double parseDouble(String value, boolean roundUp, LongSupplier now) {
         public String toString() {
             return "DocValueFormat.DateTime(" + formatter + ", " + timeZone + ", " + resolution + ")";
         }
+
+        @Override
+        public boolean equals(Object o) {
+            if (this == o) {
+                return true;
+            }
+            if (o == null || getClass() != o.getClass()) {
+                return false;
+            }
+            DateTime that = (DateTime) o;
+            return formatter.equals(that.formatter)
+                && timeZone.equals(that.timeZone)
+                && resolution == that.resolution
+                && formatSortValues == that.formatSortValues;
+        }
+
+        @Override
+        public int hashCode() {
+            return Objects.hash(formatter, timeZone, resolution, formatSortValues);
+        }
     }
 
     DocValueFormat GEOHASH = GeoHashDocValueFormat.INSTANCE;

server/src/main/java/org/elasticsearch/search/aggregations/bucket/terms/InternalSignificantTerms.java

@@ -11,6 +11,7 @@
 import org.elasticsearch.common.io.stream.StreamOutput;
 import org.elasticsearch.search.DocValueFormat;
 import org.elasticsearch.search.aggregations.Aggregations;
+import org.elasticsearch.search.aggregations.Aggregator;
 import org.elasticsearch.search.aggregations.InternalAggregation;
 import org.elasticsearch.search.aggregations.InternalAggregations;
 import org.elasticsearch.search.aggregations.InternalMultiBucketAggregation;
@@ -52,7 +53,12 @@ public interface Reader<B extends Bucket<B>> {
         long subsetSize;
         long supersetDf;
         long supersetSize;
-        long bucketOrd;
+        /**
+         * Ordinal of the bucket while it is being built. Not used after it is
+         * returned from {@link Aggregator#buildAggregations(long[])} and not
+         * serialized.
+         */
+        transient long bucketOrd;
         double score;
         protected InternalAggregations aggregations;
         final transient DocValueFormat format;
@@ -134,15 +140,14 @@ public boolean equals(Object o) {
             }
 
             Bucket<?> that = (Bucket<?>) o;
-            return bucketOrd == that.bucketOrd
-                && Double.compare(that.score, score) == 0
+            return Double.compare(that.score, score) == 0
                 && Objects.equals(aggregations, that.aggregations)
                 && Objects.equals(format, that.format);
         }
 
         @Override
         public int hashCode() {
-            return Objects.hash(getClass(), bucketOrd, aggregations, score, format);
+            return Objects.hash(getClass(), aggregations, score, format);
         }
 
         @Override

server/src/main/java/org/elasticsearch/search/aggregations/bucket/terms/InternalTerms.java

@@ -142,17 +142,23 @@ public boolean equals(Object obj) {
                 return false;
             }
             Bucket<?> that = (Bucket<?>) obj;
-            // No need to take format and showDocCountError, they are attributes
-            // of the parent terms aggregation object that are only copied here
-            // for serialization purposes
+            if (showDocCountError && docCountError != that.docCountError) {
+                /*
+                 * docCountError doesn't matter if not showing it and
+                 * serialization sets it to -1 no matter what it was
+                 * before.
+                 */
+                return false;
+            }
             return Objects.equals(docCount, that.docCount)
-                && Objects.equals(docCountError, that.docCountError)
+                && Objects.equals(showDocCountError, that.showDocCountError)
+                && Objects.equals(format, that.format)
                 && Objects.equals(aggregations, that.aggregations);
         }
 
         @Override
         public int hashCode() {
-            return Objects.hash(getClass(), docCount, docCountError, aggregations);
+            return Objects.hash(getClass(), docCount, format, showDocCountError, showDocCountError ? docCountError : -1, aggregations);
         }
     }
 

server/src/main/java/org/elasticsearch/search/aggregations/metrics/InternalCardinality.java

@@ -101,7 +101,7 @@ public XContentBuilder doXContentBody(XContentBuilder builder, Params params) th
 
     @Override
     public int hashCode() {
-        return Objects.hash(super.hashCode(), counts.hashCode(0));
+        return Objects.hash(super.hashCode(), counts == null ? 0 : counts.hashCode(0));
     }
 
     @Override
@@ -111,6 +111,9 @@ public boolean equals(Object obj) {
         if (super.equals(obj) == false) return false;
 
         InternalCardinality other = (InternalCardinality) obj;
+        if (counts == null) {
+            return other.counts == null;
+        }
         return counts.equals(0, other.counts, 0);
     }
 

server/src/main/java/org/elasticsearch/search/aggregations/metrics/InternalTopHits.java

@@ -200,7 +200,6 @@ public boolean equals(Object obj) {
             ScoreDoc otherDoc = other.topDocs.topDocs.scoreDocs[d];
             if (thisDoc.doc != otherDoc.doc) return false;
             if (Double.compare(thisDoc.score, otherDoc.score) != 0) return false;
-            if (thisDoc.shardIndex != otherDoc.shardIndex) return false;
             if (thisDoc instanceof FieldDoc) {
                 if (false == (otherDoc instanceof FieldDoc)) return false;
                 FieldDoc thisFieldDoc = (FieldDoc) thisDoc;
@@ -225,7 +224,6 @@ public int hashCode() {
             ScoreDoc doc = topDocs.topDocs.scoreDocs[d];
             hashCode = 31 * hashCode + doc.doc;
             hashCode = 31 * hashCode + Float.floatToIntBits(doc.score);
-            hashCode = 31 * hashCode + doc.shardIndex;
             if (doc instanceof FieldDoc) {
                 FieldDoc fieldDoc = (FieldDoc) doc;
                 hashCode = 31 * hashCode + Arrays.hashCode(fieldDoc.fields);

server/src/test/java/org/elasticsearch/search/aggregations/bucket/histogram/InternalAutoDateHistogramTests.java

@@ -75,7 +75,7 @@ protected InternalAutoDateHistogram createTestInstance(String name, Map<String,
             randomLongBetween(0, utcMillis("2050-01-01")),
             roundingInfos,
             roundingIndex,
-            randomNumericDocValueFormat()
+            randomDateDocValueFormat()
         );
     }
 
@@ -112,7 +112,7 @@ protected List<InternalAutoDateHistogram> randomResultsToReduce(String name, int
         long startingDate = randomLongBetween(0, utcMillis("2050-01-01"));
         RoundingInfo[] roundingInfos = AutoDateHistogramAggregationBuilder.buildRoundings(null, null);
         int roundingIndex = between(0, roundingInfos.length - 1);
-        DocValueFormat format = randomNumericDocValueFormat();
+        DocValueFormat format = randomDateDocValueFormat();
         List<InternalAutoDateHistogram> result = new ArrayList<>(size);
         for (int i = 0; i < size; i++) {
             long thisResultStart = startingDate;

server/src/test/java/org/elasticsearch/search/aggregations/bucket/histogram/InternalDateHistogramTests.java

@@ -12,11 +12,13 @@
 import org.elasticsearch.common.Rounding.DateTimeUnit;
 import org.elasticsearch.core.TimeValue;
 import org.elasticsearch.index.mapper.DateFieldMapper;
+import org.elasticsearch.index.mapper.DateFieldMapper.Resolution;
 import org.elasticsearch.search.DocValueFormat;
 import org.elasticsearch.search.aggregations.BucketOrder;
 import org.elasticsearch.search.aggregations.InternalAggregations;
 import org.elasticsearch.test.InternalMultiBucketAggregationTestCase;
 
+import java.time.ZoneOffset;
 import java.time.ZonedDateTime;
 import java.util.ArrayList;
 import java.util.HashMap;
@@ -41,7 +43,7 @@ public class InternalDateHistogramTests extends InternalMultiBucketAggregationTe
     public void setUp() throws Exception {
         super.setUp();
         keyed = randomBoolean();
-        format = randomNumericDocValueFormat();
+        format = randomDateDocValueFormat();
         // in order for reduction to work properly (and be realistic) we need to use the same interval, minDocCount, emptyBucketInfo
         // and base in all randomly created aggs as part of the same test run. This is particularly important when minDocCount is
         // set to 0 as empty buckets need to be added to fill the holes.
@@ -69,6 +71,26 @@ public void setUp() throws Exception {
 
     @Override
     protected InternalDateHistogram createTestInstance(String name, Map<String, Object> metadata, InternalAggregations aggregations) {
+        return createTestInstance(name, metadata, aggregations, format);
+    }
+
+    @Override
+    protected InternalDateHistogram createTestInstanceForXContent(String name, Map<String, Object> metadata, InternalAggregations subAggs) {
+        // We have to force a format that won't throw away precision and cause duplicate fields
+        DocValueFormat xContentCompatibleFormat = new DocValueFormat.DateTime(
+            DateFieldMapper.DEFAULT_DATE_TIME_FORMATTER,
+            ZoneOffset.UTC,
+            Resolution.MILLISECONDS
+        );
+        return createTestInstance(name, metadata, subAggs, xContentCompatibleFormat);
+    }
+
+    private InternalDateHistogram createTestInstance(
+        String name,
+        Map<String, Object> metadata,
+        InternalAggregations aggregations,
+        DocValueFormat format
+    ) {
         int nbBuckets = randomNumberOfBuckets();
         List<InternalDateHistogram.Bucket> buckets = new ArrayList<>(nbBuckets);
         // avoid having different random instance start from exactly the same base

server/src/test/java/org/elasticsearch/search/aggregations/bucket/range/InternalDateRangeTests.java

@@ -31,7 +31,7 @@ public class InternalDateRangeTests extends InternalRangeTestCase<InternalDateRa
     @Override
     public void setUp() throws Exception {
         super.setUp();
-        format = randomNumericDocValueFormat();
+        format = randomDateDocValueFormat();
 
         Function<DateTime, DateTime> interval = randomFrom(
             dateTime -> dateTime.plusSeconds(1),

server/src/test/java/org/elasticsearch/search/aggregations/bucket/range/RangeAggregatorTests.java

@@ -470,11 +470,11 @@ public void testUnmappedWithBadMissingField() {
     public void testSubAggCollectsFromSingleBucketIfOneRange() throws IOException {
         RangeAggregationBuilder aggregationBuilder = new RangeAggregationBuilder("test").field(NUMBER_FIELD_NAME)
             .addRange(0d, 10d)
-            .subAggregation(aggCardinality("c"));
+            .subAggregation(aggCardinalityUpperBound("c"));
 
         simpleTestCase(aggregationBuilder, new MatchAllDocsQuery(), range -> {
             List<? extends InternalRange.Bucket> ranges = range.getBuckets();
-            InternalAggCardinality pc = ranges.get(0).getAggregations().get("c");
+            InternalAggCardinalityUpperBound pc = ranges.get(0).getAggregations().get("c");
             assertThat(pc.cardinality(), equalTo(CardinalityUpperBound.ONE));
         });
     }
@@ -483,11 +483,11 @@ public void testSubAggCollectsFromManyBucketsIfManyRanges() throws IOException {
         RangeAggregationBuilder aggregationBuilder = new RangeAggregationBuilder("test").field(NUMBER_FIELD_NAME)
             .addRange(0d, 10d)
             .addRange(10d, 100d)
-            .subAggregation(aggCardinality("c"));
+            .subAggregation(aggCardinalityUpperBound("c"));
 
         simpleTestCase(aggregationBuilder, new MatchAllDocsQuery(), range -> {
             List<? extends InternalRange.Bucket> ranges = range.getBuckets();
-            InternalAggCardinality pc = ranges.get(0).getAggregations().get("c");
+            InternalAggCardinalityUpperBound pc = ranges.get(0).getAggregations().get("c");
             assertThat(pc.cardinality().map(i -> i), equalTo(2));
             pc = ranges.get(1).getAggregations().get("c");
             assertThat(pc.cardinality().map(i -> i), equalTo(2));