From 6fdeb792cb168ddadbd923e37efcb0bf5cfc6780 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Christoph=20B=C3=BCscher?= <christophbuescher@posteo.de>
Date: Tue, 24 Sep 2024 18:10:22 +0200
Subject: [PATCH] Add full cluster restart test

---
 .../upgrades/FullClusterRestartIT.java        | 101 ++++++++++++++++++
 1 file changed, 101 insertions(+)

diff --git a/qa/full-cluster-restart/src/javaRestTest/java/org/elasticsearch/upgrades/FullClusterRestartIT.java b/qa/full-cluster-restart/src/javaRestTest/java/org/elasticsearch/upgrades/FullClusterRestartIT.java
index d4090909ee82d..5d162a39f4a69 100644
--- a/qa/full-cluster-restart/src/javaRestTest/java/org/elasticsearch/upgrades/FullClusterRestartIT.java
+++ b/qa/full-cluster-restart/src/javaRestTest/java/org/elasticsearch/upgrades/FullClusterRestartIT.java
@@ -32,6 +32,7 @@
 import org.elasticsearch.index.IndexSettings;
 import org.elasticsearch.index.IndexVersion;
 import org.elasticsearch.index.IndexVersions;
+import org.elasticsearch.index.analysis.Analysis;
 import org.elasticsearch.index.mapper.DateFieldMapper;
 import org.elasticsearch.rest.action.admin.indices.RestPutIndexTemplateAction;
 import org.elasticsearch.test.NotEqualMessageBuilder;
@@ -1726,6 +1727,106 @@ public void testSystemIndexMetadataIsUpgraded() throws Exception {
         }
     }
 
+    /**
+     * This test ensures that search results on old indices using "persian" analyzer don't change
+     * after we introduce Lucene 10
+     */
+    public void testPersianAnalyzerBWC() throws Exception {
+        var originalClusterLegacyPersianAnalyzer = oldClusterHasFeature(Analysis.PERSIAN_ANALYZER_WITH_STEMMER) == false;
+        assumeTrue("Don't run this test if both versions already support stemming", originalClusterLegacyPersianAnalyzer);
+        final String indexName = "test_persian_stemmer";
+        Settings idxSettings = indexSettings(1, 1).build();
+        String mapping = """
+                {
+                  "properties": {
+                    "textfield" : {
+                      "type": "text",
+                      "analyzer": "persian"
+                    }
+                  }
+                }
+            """;
+
+        String query = """
+                {
+                  "query": {
+                    "match": {
+                      "textfield": "كتابها"
+                    }
+                  }
+                }
+            """;
+
+        if (isRunningAgainstOldCluster()) {
+            createIndex(client(), indexName, idxSettings, mapping);
+            ensureGreen(indexName);
+
+            assertOK(
+                client().performRequest(
+                    newXContentRequest(
+                        HttpMethod.POST,
+                        "/" + indexName + "/" + "_doc/1",
+                        (builder, params) -> builder.field("textfield", "كتابها")
+                    )
+                )
+            );
+            assertOK(
+                client().performRequest(
+                    newXContentRequest(
+                        HttpMethod.POST,
+                        "/" + indexName + "/" + "_doc/2",
+                        (builder, params) -> builder.field("textfield", "كتاب")
+                    )
+                )
+            );
+            refresh(indexName);
+
+            assertNumHits(indexName, 2, 1);
+
+            Request searchRequest = new Request("POST", "/" + indexName + "/_search");
+            searchRequest.setJsonEntity(query);
+            assertTotalHits(1, entityAsMap(client().performRequest(searchRequest)));
+        } else {
+            // old index should still only return one doc
+            Request searchRequest = new Request("POST", "/" + indexName + "/_search");
+            searchRequest.setJsonEntity(query);
+            assertTotalHits(1, entityAsMap(client().performRequest(searchRequest)));
+
+            String newIndexName = indexName + "_new";
+            createIndex(client(), newIndexName, idxSettings, mapping);
+            ensureGreen(newIndexName);
+
+            assertOK(
+                client().performRequest(
+                    newXContentRequest(
+                        HttpMethod.POST,
+                        "/" + newIndexName + "/" + "_doc/1",
+                        (builder, params) -> builder.field("textfield", "كتابها")
+                    )
+                )
+            );
+            assertOK(
+                client().performRequest(
+                    newXContentRequest(
+                        HttpMethod.POST,
+                        "/" + newIndexName + "/" + "_doc/2",
+                        (builder, params) -> builder.field("textfield", "كتاب")
+                    )
+                )
+            );
+            refresh(newIndexName);
+
+            searchRequest = new Request("POST", "/" + newIndexName + "/_search");
+            searchRequest.setJsonEntity(query);
+            assertTotalHits(2, entityAsMap(client().performRequest(searchRequest)));
+
+            // searching both indices (old and new analysis version) we should get 1 hit from the old and 2 from the new index
+            searchRequest = new Request("POST", "/" + indexName + "," + newIndexName + "/_search");
+            searchRequest.setJsonEntity(query);
+            assertTotalHits(3, entityAsMap(client().performRequest(searchRequest)));
+        }
+    }
+
     /**
      * This test ensures that soft deletes are enabled a when upgrading a pre-8 cluster to 8.0+
      */