Aggs must specify a `field` or `script` (or both) (#52226)

This adds a validation to VSParserHelper to ensure that a field or
script or both are specified by the user.  This is technically
required today already, but throws an exception much deeper
in the agg framework and has a very unintuitive error for the user
(as well as eating more resources instead of failing early)

docs/reference/aggregations/bucket/range-aggregation.asciidoc

@@ -379,30 +379,3 @@ Response:
 }
 --------------------------------------------------
 // TESTRESPONSE[s/\.\.\.//]
-
-If a sub aggregation is also based on the same value source as the range aggregation (like the `stats` aggregation in the example above) it is possible to leave out the value source definition for it. The following will return the same response as above:
-
-[source,console]
---------------------------------------------------
-GET /_search
-{
-    "aggs" : {
-        "price_ranges" : {
-            "range" : {
-                "field" : "price",
-                "ranges" : [
-                    { "to" : 100 },
-                    { "from" : 100, "to" : 200 },
-                    { "from" : 200 }
-                ]
-            },
-            "aggs" : {
-                "price_stats" : {
-                    "stats" : {} <1>
-                }
-            }
-        }
-    }
-}
---------------------------------------------------
-<1> We don't need to specify the `price` as we "inherit" it by default from the parent `range` aggregation

rest-api-spec/src/main/resources/rest-api-spec/test/search.aggregation/20_terms.yml

@@ -765,6 +765,18 @@ setup:
 
   - gt: { indices.test_1.total.fielddata.memory_size_in_bytes: 0}
 
+---
+"No field or script":
+  - skip:
+      version: " - 7.7.99"
+      reason:  "Exception was a deep, server exception before 7.8"
+  - do:
+      catch: /Required one of fields \[field, script\], but none were specified/
+      search:
+        rest_total_hits_as_int: true
+        index: test_1
+        body: { "size" : 0, "aggs" : { "no_field_terms" : { "terms" : { "size": 1 } } } }
+
 
 
 

server/src/main/java/org/elasticsearch/search/aggregations/support/ValuesSourceAggregationBuilder.java

@@ -66,6 +66,10 @@ public abstract class ValuesSourceAggregationBuilder<AB extends ValuesSourceAggr
             objectParser.declareField(ValuesSourceAggregationBuilder::script,
                     (parser, context) -> Script.parse(parser),
                     Script.SCRIPT_PARSE_FIELD, ObjectParser.ValueType.OBJECT_OR_STRING);
+            String[] fields = new String[]{ParseField.CommonFields.FIELD.getPreferredName(), Script.SCRIPT_PARSE_FIELD.getPreferredName()};
+            objectParser.declareRequiredFieldSet(fields);
+        } else {
+            objectParser.declareRequiredFieldSet(ParseField.CommonFields.FIELD.getPreferredName());
         }
 
         if (timezoneAware) {

server/src/test/java/org/elasticsearch/search/aggregations/AggregatorFactoriesBuilderTests.java

@@ -139,13 +139,13 @@ public class AggregatorFactoriesBuilderTests extends AbstractSerializingTestCase
         final int randomAggregatorPoolSize = 4;
         switch (randomIntBetween(1, randomAggregatorPoolSize)) {
         case 1:
-            return AggregationBuilders.avg(randomAlphaOfLengthBetween(3, 10));
+            return AggregationBuilders.avg(randomAlphaOfLengthBetween(3, 10)).field("foo");
         case 2:
-            return AggregationBuilders.min(randomAlphaOfLengthBetween(3, 10));
+            return AggregationBuilders.min(randomAlphaOfLengthBetween(3, 10)).field("foo");
         case 3:
-            return AggregationBuilders.max(randomAlphaOfLengthBetween(3, 10));
+            return AggregationBuilders.max(randomAlphaOfLengthBetween(3, 10)).field("foo");
         case 4:
-            return AggregationBuilders.sum(randomAlphaOfLengthBetween(3, 10));
+            return AggregationBuilders.sum(randomAlphaOfLengthBetween(3, 10)).field("foo");
         }
 
         // never reached

server/src/test/java/org/elasticsearch/search/aggregations/bucket/GeoHashGridTests.java

@@ -42,6 +42,7 @@ public class GeoHashGridTests extends BaseAggregationTestCase<GeoGridAggregation
     protected GeoHashGridAggregationBuilder createTestAggregatorBuilder() {
         String name = randomAlphaOfLengthBetween(3, 20);
         GeoHashGridAggregationBuilder factory = new GeoHashGridAggregationBuilder(name);
+        factory.field("foo");
         if (randomBoolean()) {
             int precision = randomIntBetween(1, 12);
             factory.precision(precision);

server/src/test/java/org/elasticsearch/search/aggregations/bucket/GeoTileGridTests.java

@@ -43,6 +43,7 @@ public class GeoTileGridTests extends BaseAggregationTestCase<GeoGridAggregation
     protected GeoTileGridAggregationBuilder createTestAggregatorBuilder() {
         String name = randomAlphaOfLengthBetween(3, 20);
         GeoTileGridAggregationBuilder factory = new GeoTileGridAggregationBuilder(name);
+        factory.field("foo");
         if (randomBoolean()) {
             factory.precision(randomIntBetween(0, GeoTileUtils.MAX_ZOOM));
         }

test/framework/src/main/java/org/elasticsearch/search/RandomSearchRequestGenerator.java

@@ -348,7 +348,7 @@ public class RandomSearchRequestGenerator {
             }
         }
         if (randomBoolean()) {
-            builder.aggregation(AggregationBuilders.avg(randomAlphaOfLengthBetween(5, 20)));
+            builder.aggregation(AggregationBuilders.avg(randomAlphaOfLengthBetween(5, 20)).field("foo"));
         }
         if (randomBoolean()) {
             builder.ext(randomExtBuilders.get());

x-pack/plugin/analytics/src/test/java/org/elasticsearch/xpack/analytics/stringstats/StringStatsAggregationBuilderTests.java

@@ -54,6 +54,7 @@ public class StringStatsAggregationBuilderTests extends AbstractSerializingTestC
     @Override
     protected StringStatsAggregationBuilder createTestInstance() {
         StringStatsAggregationBuilder builder = new StringStatsAggregationBuilder(randomAlphaOfLength(5));
+        builder.field("foo");
         builder.showDistribution(randomBoolean());
         return builder;
     }
@@ -92,6 +93,8 @@ public class StringStatsAggregationBuilderTests extends AbstractSerializingTestC
             StringStatsAggregationBuilder serverBuilder) {
         org.elasticsearch.client.analytics.StringStatsAggregationBuilder builder =
                 new org.elasticsearch.client.analytics.StringStatsAggregationBuilder(serverBuilder.getName());
-        return builder.showDistribution(serverBuilder.showDistribution());
+        return builder
+            .showDistribution(serverBuilder.showDistribution())
+            .field(serverBuilder.field());
     }
 }