Guard against project_routing in non-CPS env for PIT and Field Caps (#138867)

In CPS we support project_routing either as query parameter or in the
body of the request. With this change we throw a bad request error if
project_routing is set in non-CPS env.

Author: piergm

qa/smoke-test-http/src/internalClusterTest/java/org/elasticsearch/http/FieldCapabilitiesIT.java

@@ -0,0 +1,42 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the "Elastic License
+ * 2.0", the "GNU Affero General Public License v3.0 only", and the "Server Side
+ * Public License v 1"; you may not use this file except in compliance with, at
+ * your election, the "Elastic License 2.0", the "GNU Affero General Public
+ * License v3.0 only", or the "Server Side Public License, v 1".
+ */
+
+package org.elasticsearch.http;
+
+import org.apache.http.HttpStatus;
+import org.elasticsearch.client.Request;
+import org.elasticsearch.client.ResponseException;
+
+import static org.hamcrest.Matchers.containsString;
+import static org.hamcrest.Matchers.equalTo;
+
+public class FieldCapabilitiesIT extends HttpSmokeTestCase {
+
+    public void testProjectRoutingInNonCrossProjectEnv() {
+        // With project_routing as query param in non-CPS env
+        {
+            Request request = new Request("POST", "_field_caps?fields=*&project_routing=_alias:_origin");
+            ResponseException error = expectThrows(ResponseException.class, () -> getRestClient().performRequest(request));
+            assertThat(error.getMessage(), containsString("request [_field_caps] contains unrecognized parameter: [project_routing]"));
+            assertThat(error.getResponse().getStatusLine().getStatusCode(), equalTo(HttpStatus.SC_BAD_REQUEST));
+        }
+        // With project_routing in body in non-CPS env
+        {
+            Request request = new Request("POST", "_field_caps?fields=*");
+            request.setJsonEntity("""
+                {
+                    "project_routing": "_alias:_origin"
+                }
+                """);
+            ResponseException error = expectThrows(ResponseException.class, () -> getRestClient().performRequest(request));
+            assertThat(error.getMessage(), containsString("Unknown key for a VALUE_STRING in [project_routing]"));
+            assertThat(error.getResponse().getStatusLine().getStatusCode(), equalTo(HttpStatus.SC_BAD_REQUEST));
+        }
+    }
+}

qa/smoke-test-http/src/internalClusterTest/java/org/elasticsearch/http/PointInTimeIT.java

@@ -44,4 +44,28 @@ public void testMissingRequiredParameters() {
             assertThat(error.getResponse().getStatusLine().getStatusCode(), equalTo(HttpStatus.SC_BAD_REQUEST));
         }
     }
+
+    public void testProjectRoutingInNonCrossProjectEnv() {
+        // With project_routing as query param in non-CPS env
+        {
+            Request request = new Request("POST", "_pit?project_routing=_alias:_origin");
+            request.addParameter("keep_alive", "1m");
+            ResponseException error = expectThrows(ResponseException.class, () -> getRestClient().performRequest(request));
+            assertThat(error.getMessage(), containsString("request [_pit] contains unrecognized parameter: [project_routing]"));
+            assertThat(error.getResponse().getStatusLine().getStatusCode(), equalTo(HttpStatus.SC_BAD_REQUEST));
+        }
+        // With project_routing in body in non-CPS env
+        {
+            Request request = new Request("POST", "logs-*/_pit");
+            request.addParameter("keep_alive", "1m");
+            request.setJsonEntity("""
+                {
+                    "project_routing": "_alias:_origin"
+                }
+                """);
+            ResponseException error = expectThrows(ResponseException.class, () -> getRestClient().performRequest(request));
+            assertThat(error.getMessage(), containsString("Unknown key for a VALUE_STRING in [project_routing]"));
+            assertThat(error.getResponse().getStatusLine().getStatusCode(), equalTo(HttpStatus.SC_BAD_REQUEST));
+        }
+    }
 }

server/src/main/java/org/elasticsearch/action/fieldcaps/FieldCapabilitiesRequest.java

@@ -355,6 +355,13 @@ public ActionRequestValidationException validate() {
         if (fields == null || fields.length == 0) {
             validationException = ValidateActions.addValidationError("no fields specified", validationException);
         }
+        if (projectRouting != null && indicesOptions.resolveCrossProjectIndexExpression() == false) {
+            validationException = ValidateActions.addValidationError(
+                "Unknown key for a VALUE_STRING in [project_routing]",
+                validationException
+            );
+
+        }
         return validationException;
     }
 

server/src/main/java/org/elasticsearch/action/search/OpenPointInTimeRequest.java

@@ -14,6 +14,7 @@
 import org.elasticsearch.action.IndicesRequest;
 import org.elasticsearch.action.LegacyActionRequest;
 import org.elasticsearch.action.ResolvedIndexExpressions;
+import org.elasticsearch.action.ValidateActions;
 import org.elasticsearch.action.support.IndicesOptions;
 import org.elasticsearch.common.io.stream.StreamInput;
 import org.elasticsearch.common.io.stream.StreamOutput;
@@ -104,6 +105,13 @@ public ActionRequestValidationException validate() {
         if (keepAlive == null) {
             validationException = addValidationError("[keep_alive] is not specified", validationException);
         }
+        if (projectRouting != null && indicesOptions.resolveCrossProjectIndexExpression() == false) {
+            validationException = ValidateActions.addValidationError(
+                "Unknown key for a VALUE_STRING in [project_routing]",
+                validationException
+            );
+
+        }
         return validationException;
     }
 

server/src/main/java/org/elasticsearch/rest/action/RestFieldCapabilitiesAction.java

@@ -61,7 +61,7 @@ public RestChannelConsumer prepareRequest(final RestRequest request, final NodeC
         final FieldCapabilitiesRequest fieldRequest = new FieldCapabilitiesRequest();
 
         final boolean crossProjectEnabled = crossProjectModeDecider.crossProjectEnabled();
-        if (crossProjectModeDecider.crossProjectEnabled()) {
+        if (crossProjectEnabled) {
             fieldRequest.projectRouting(request.param("project_routing", null));
             // Setting includeResolvedTo to always include index resolution data structure in the linked project responses,
             // in order to allow the coordinating node to call CrossProjectIndexResolutionValidator#validate