fix(sitesearch): preserve the custom index alias across a crawl (#36983)

dotCMS/src/enterprise/java/com/dotcms/enterprise/publishing/sitesearch/ESSiteSearchAPI.java

@@ -46,6 +46,7 @@
 import java.util.Date;
 import java.util.List;
 import java.util.Map;
+import java.util.Optional;
 import java.util.stream.Collectors;
 
 import io.vavr.control.Try;
@@ -370,9 +371,16 @@ public SiteSearchResults search(String indexName, String query, int offset, int
      * @return
      * @throws DotDataException
      */
+    @Override
+    public Optional<String> defaultIndexName() throws DotDataException {
+        return Optional.ofNullable(indiciesAPI.loadIndicies().getSiteSearch());
+    }
+
     @Override
     public boolean isDefaultIndex(final String indexName) throws DotDataException {
-       return  indexName.equals(indiciesAPI.loadIndicies().getSiteSearch());
+        // Defined in terms of defaultIndexName so "which index is the default" has one definition
+        // per engine (issue #36983).
+        return indexName != null && defaultIndexName().filter(indexName::equals).isPresent();
     }
 
     @Override

dotCMS/src/enterprise/java/com/dotcms/enterprise/publishing/sitesearch/OSSiteSearchAPI.java

@@ -519,9 +519,16 @@ public Map<String, Aggregation> getFacets(String indexName, String query) throws
     // Default index activation / inspection
     // =========================================================================
 
+    @Override
+    public Optional<String> defaultIndexName() {
+        return defaultSiteSearchIndex();
+    }
+
     @Override
     public boolean isDefaultIndex(final String indexName) throws DotDataException {
-        return indexName != null && indexName.equals(defaultSiteSearchIndex().orElse(null));
+        // Defined in terms of defaultIndexName so "which index is the default" has one definition
+        // per engine (issue #36983).
+        return indexName != null && defaultIndexName().filter(indexName::equals).isPresent();
     }
 
     @Override

dotCMS/src/enterprise/java/com/dotcms/enterprise/publishing/sitesearch/SiteSearchAPIImpl.java

@@ -25,9 +25,11 @@
 import java.text.ParseException;
 import java.util.ArrayList;
 import java.util.HashMap;
+import java.util.LinkedHashMap;
 import java.util.LinkedHashSet;
 import java.util.List;
 import java.util.Map;
+import java.util.Optional;
 import java.util.Set;
 import org.quartz.SchedulerException;
 
@@ -201,6 +203,33 @@ public Map<String, String> getAliasToIndexMap() {
         return router.read(SiteSearchAPI::getAliasToIndexMap);
     }
 
+    /**
+     * Router: alias resolution over the SAME provider set {@link #listIndices()} uses, so every listed
+     * index can show its alias — the management/display view (issue #36983).
+     *
+     * <p>Deliberately NOT the read provider alone. The list is a union in the dual-write phases, so an
+     * index living only on the other engine would otherwise render with a blank alias: Phase 2 + a
+     * Phase-0 (ES-only) index, or Phase 1 + a Phase-3 (OS-only) index after a downgrade. Merging over
+     * the write providers keeps the alias view and the index list exactly in step.</p>
+     *
+     * <p>The read provider is applied last so it wins any collision: if the two engines resolve one
+     * alias to different logical indices (a mirror desync), the map agrees with what a search would
+     * actually hit. In the single-provider phases (0 and 3) there is nothing to merge.</p>
+     */
+    @Override
+    public Map<String, String> getAliasToIndexMapAllEngines() {
+        final List<SiteSearchAPI> providers = router.writeProviders();
+        if (providers.size() == 1) {
+            return providers.getFirst().getAliasToIndexMap();
+        }
+        final SiteSearchAPI readProvider = router.readProvider();
+        final Map<String, String> merged = new LinkedHashMap<>();
+        providers.stream().filter(provider -> provider != readProvider)
+                .forEach(provider -> merged.putAll(provider.getAliasToIndexMap()));
+        merged.putAll(readProvider.getAliasToIndexMap()); // last write wins → read provider
+        return merged;
+    }
+
     // -------------------------------------------------------------------------
     // Reads — read provider
     // -------------------------------------------------------------------------
@@ -221,6 +250,23 @@ public SiteSearchResult getFromIndex(final String index, final String id) {
         return router.read(impl -> impl.getFromIndex(index, id));
     }
 
+    /**
+     * Router: the default site-search index according to the current read provider — Elasticsearch's
+     * legacy pointer in Phases 0/1, OpenSearch's {@code VersionedIndices} (with a legacy fallback) in
+     * Phases 2/3. Reading the legacy pointer directly goes stale from Phase 3 on, where
+     * {@code activateIndex} fans out to OpenSearch alone (issue #36983).
+     */
+    @Override
+    public Optional<String> defaultIndexName() throws DotDataException {
+        try {
+            return router.readChecked(SiteSearchAPI::defaultIndexName);
+        } catch (DotDataException e) {
+            throw e;
+        } catch (Exception e) {
+            throw new DotDataException(e.getMessage(), e);
+        }
+    }
+
     @Override
     public boolean isDefaultIndex(final String indexName) throws DotDataException {
         try {