ES|QL: Enable CCS tests for FORK (elastic#139302)

Author: ioanatia

x-pack/plugin/esql/qa/server/multi-clusters/src/javaRestTest/java/org/elasticsearch/xpack/esql/ccq/MultiClusterSpecIT.java

@@ -48,6 +48,7 @@
 import static org.elasticsearch.xpack.esql.CsvTestsDataLoader.CSV_DATASET_MAP;
 import static org.elasticsearch.xpack.esql.CsvTestsDataLoader.ENRICH_SOURCE_INDICES;
 import static org.elasticsearch.xpack.esql.EsqlTestUtils.classpathResources;
+import static org.elasticsearch.xpack.esql.action.EsqlCapabilities.Cap.ENABLE_FORK_FOR_REMOTE_INDICES_V2;
 import static org.elasticsearch.xpack.esql.action.EsqlCapabilities.Cap.ENABLE_LOOKUP_JOIN_ON_REMOTE;
 import static org.elasticsearch.xpack.esql.action.EsqlCapabilities.Cap.FORK_V9;
 import static org.elasticsearch.xpack.esql.action.EsqlCapabilities.Cap.INLINE_STATS;
@@ -167,7 +168,12 @@ protected void shouldSkipTest(String testName) throws IOException {
         // Tests that do SORT before LOOKUP JOIN - not supported in CCS
         assumeFalse("LOOKUP JOIN after SORT not yet supported in CCS", testName.contains("OnTheCoordinator"));
 
-        assumeFalse("FORK not yet supported with CCS", testCase.requiredCapabilities.contains(FORK_V9.capabilityName()));
+        if (testCase.requiredCapabilities.contains(FORK_V9.capabilityName())) {
+            assumeTrue(
+                "FORK not yet supported with CCS",
+                hasCapabilities(adminClient(), List.of(ENABLE_FORK_FOR_REMOTE_INDICES_V2.capabilityName()))
+            );
+        }
     }
 
     private TestFeatureService remoteFeaturesService() throws IOException {

x-pack/plugin/esql/qa/testFixtures/src/main/resources/subquery.csv-spec

@@ -319,10 +319,9 @@ null           | null              | 4        | 172.21.3.15
 ;
 
 subqueryWithCountStarAndDateTrunc
-required_capability: fork_v9
 required_capability: subquery_in_from_command
 
-FROM employees, (FROM sample_data
+FROM employees, (FROM sample_data metadata _index
                                 | STATS cnt = count(*) by ts=date_trunc(1 hour, @timestamp)
                                 | SORT cnt DESC
                                 )

x-pack/plugin/esql/src/main/java/org/elasticsearch/xpack/esql/action/EsqlCapabilities.java

@@ -1469,7 +1469,7 @@ public enum Cap {
         /**
          * FORK with remote indices
          */
-        ENABLE_FORK_FOR_REMOTE_INDICES(Build.current().isSnapshot()),
+        ENABLE_FORK_FOR_REMOTE_INDICES_V2(Build.current().isSnapshot()),
 
         /**
          * Support for the Present function

x-pack/plugin/esql/src/main/java/org/elasticsearch/xpack/esql/parser/LogicalPlanBuilder.java

@@ -972,7 +972,7 @@ public PlanFactory visitForkCommand(EsqlBaseParser.ForkCommandContext ctx) {
         }
 
         return input -> {
-            if (EsqlCapabilities.Cap.ENABLE_FORK_FOR_REMOTE_INDICES.isEnabled() == false) {
+            if (EsqlCapabilities.Cap.ENABLE_FORK_FOR_REMOTE_INDICES_V2.isEnabled() == false) {
                 checkForRemoteClusters(input, source(ctx), "FORK");
             }
             List<LogicalPlan> subPlans = subQueries.stream().map(planFactory -> planFactory.apply(input)).toList();

x-pack/plugin/esql/src/test/java/org/elasticsearch/xpack/esql/parser/StatementParserTests.java

@@ -3580,7 +3580,7 @@ public void testInvalidFork() {
         expectError("FROM foo* | FORK (where true) ()", "line 1:32: mismatched input ')'");
         expectError("FROM foo* | FORK () (where true)", "line 1:19: mismatched input ')'");
 
-        if (EsqlCapabilities.Cap.ENABLE_FORK_FOR_REMOTE_INDICES.isEnabled() == false) {
+        if (EsqlCapabilities.Cap.ENABLE_FORK_FOR_REMOTE_INDICES_V2.isEnabled() == false) {
             var fromPatterns = randomIndexPatterns(CROSS_CLUSTER);
             expectError(
                 "FROM " + fromPatterns + " | FORK (EVAL a = 1) (EVAL a = 2)",