Fix: Add NamedWriteable for RuleQueryRankDoc (elastic#128153)

* Add NamedWriteable for QueryRule rank doc

* Update test

* Update docs/changelog/128153.yaml

* Add multi cluster test for query rules

* Commenting out code - explicitly trying to spur a test failure

* [CI] Auto commit changes from spotless

* Streamline test for multi cluster

* Revert changes to try to break test

* Fix compile error

---------

Co-authored-by: elasticsearchmachine <[email protected]>
(cherry picked from commit b335c1a)

# Conflicts:
#	x-pack/plugin/ent-search/src/yamlRestTest/resources/rest-api-spec/test/entsearch/rules/40_rule_query_search.yml

Author: kderusso

docs/changelog/128153.yaml

@@ -0,0 +1,6 @@
+pr: 128153
+summary: "Fix: Add `NamedWriteable` for `RuleQueryRankDoc`"
+area: Relevance
+type: bug
+issues:
+ - 126071

x-pack/plugin/ent-search/src/main/java/org/elasticsearch/xpack/application/EnterpriseSearch.java

@@ -30,6 +30,7 @@
 import org.elasticsearch.plugins.SystemIndexPlugin;
 import org.elasticsearch.rest.RestController;
 import org.elasticsearch.rest.RestHandler;
+import org.elasticsearch.search.rank.RankDoc;
 import org.elasticsearch.xcontent.ParseField;
 import org.elasticsearch.xpack.application.analytics.AnalyticsTemplateRegistry;
 import org.elasticsearch.xpack.application.analytics.action.DeleteAnalyticsCollectionAction;
@@ -179,6 +180,7 @@
 import org.elasticsearch.xpack.application.rules.action.TransportPutQueryRulesetAction;
 import org.elasticsearch.xpack.application.rules.action.TransportTestQueryRulesetAction;
 import org.elasticsearch.xpack.application.rules.retriever.QueryRuleRetrieverBuilder;
+import org.elasticsearch.xpack.application.rules.retriever.RuleQueryRankDoc;
 import org.elasticsearch.xpack.application.search.SearchApplicationIndexService;
 import org.elasticsearch.xpack.application.search.action.DeleteSearchApplicationAction;
 import org.elasticsearch.xpack.application.search.action.GetSearchApplicationAction;
@@ -351,6 +353,11 @@ protected XPackLicenseState getLicenseState() {
         return Collections.unmodifiableList(actionHandlers);
     }
 
+    @Override
+    public List<NamedWriteableRegistry.Entry> getNamedWriteables() {
+        return List.of(new NamedWriteableRegistry.Entry(RankDoc.class, RuleQueryRankDoc.NAME, RuleQueryRankDoc::new));
+    }
+
     @Override
     public List<RestHandler> getRestHandlers(
         Settings settings,

x-pack/plugin/ent-search/src/yamlRestTest/resources/rest-api-spec/test/entsearch/rules/40_rule_query_search.yml

@@ -893,3 +893,82 @@ teardown:
   - match: { hits.total.value: 2 }
   - match: { hits.hits.0._id: 'doc1' }
   - match: { hits.hits.1._id: 'doc4' }
+
+---
+"Multi-index search with missing documents does not error":
+  - requires:
+      cluster_features: [ "test_rule_retriever.with_indices_that_dont_return_rank_docs" ]
+      reason: "Fixed"
+
+  - do:
+      indices.create:
+        index: test-index-001
+        body:
+          settings:
+            index:
+              number_of_shards: 5 # Ensure more shards than docs
+
+  - do:
+      indices.create:
+        index: test-index-002
+        body:
+          settings:
+            index:
+              number_of_shards: 5 # Ensure more shards than docs
+
+  - do:
+      bulk:
+        refresh: true
+        index: test-index-001
+        body:
+          - index:
+              _id: 1
+          - { "text": "patio" }
+          - index:
+              _id: 2
+          - { "text": "catio" }
+
+  - do:
+      bulk:
+        refresh: true
+        index: test-index-002
+        body:
+          - index:
+              _id: 3
+          - { "text": "balcony" }
+          - index:
+              _id: 4
+          - { "text": "overhang" }
+
+  - do:
+      query_rules.put_ruleset:
+        ruleset_id: catio-ruleset
+        body:
+          rules:
+            - rule_id: rule1
+              type: pinned
+              criteria:
+                - type: exact
+                  metadata: foo
+                  values: [ bar ]
+              actions:
+                ids:
+                  - '2'
+
+  - do:
+      search:
+        index: test-index-001,test-index-002
+        body:
+          retriever:
+            rule:
+              retriever:
+                standard:
+                  query:
+                    query_string:
+                      query: "patio or balcony"
+              match_criteria:
+                foo: bar
+              ruleset_ids: catio-ruleset
+
+  - match: { hits.total.value: 3 }
+  - match: { hits.hits.0._id: '2' }