Simplify logic around missing shards check in search phases

This removes a couple of indirections: the error message for missing shards is always the
same no matter the search phase.

Author: javanna

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

@@ -201,7 +201,7 @@ private synchronized void consumeResult(int shardIndex, boolean canMatch, MinAnd
 
     private void checkNoMissingShards(List<SearchShardIterator> shards) {
         assert assertSearchCoordinationThread();
-        SearchPhase.doCheckNoMissingShards("can_match", request, shards, SearchPhase::makeMissingShardsError);
+        SearchPhase.doCheckNoMissingShards("can_match", request, shards);
     }
 
     private Map<SendingTarget, List<SearchShardIterator>> groupByNode(List<SearchShardIterator> shards) {

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

@@ -14,7 +14,6 @@
 
 import java.util.List;
 import java.util.Objects;
-import java.util.function.Function;
 
 /**
  * Base class for all individual search phases like collecting distributed frequencies, fetching documents, querying shards.
@@ -35,26 +34,13 @@ public String getName() {
         return name;
     }
 
-    protected String missingShardsErrorMessage(StringBuilder missingShards) {
-        return makeMissingShardsError(missingShards);
-    }
-
-    protected static String makeMissingShardsError(StringBuilder missingShards) {
+    private static String makeMissingShardsError(StringBuilder missingShards) {
         return "Search rejected due to missing shards ["
             + missingShards
             + "]. Consider using `allow_partial_search_results` setting to bypass this error.";
     }
 
-    protected void doCheckNoMissingShards(String phaseName, SearchRequest request, List<SearchShardIterator> shardsIts) {
-        doCheckNoMissingShards(phaseName, request, shardsIts, this::missingShardsErrorMessage);
-    }
-
-    protected static void doCheckNoMissingShards(
-        String phaseName,
-        SearchRequest request,
-        List<SearchShardIterator> shardsIts,
-        Function<StringBuilder, String> makeErrorMessage
-    ) {
+    protected static void doCheckNoMissingShards(String phaseName, SearchRequest request, List<SearchShardIterator> shardsIts) {
         assert request.allowPartialSearchResults() != null : "SearchRequest missing setting for allowPartialSearchResults";
         if (request.allowPartialSearchResults() == false) {
             final StringBuilder missingShards = new StringBuilder();
@@ -70,7 +56,7 @@ protected static void doCheckNoMissingShards(
             }
             if (missingShards.isEmpty() == false) {
                 // Status red - shard is missing all copies and would produce partial results for an index search
-                final String msg = makeErrorMessage.apply(missingShards);
+                final String msg = makeMissingShardsError(missingShards);
                 throw new SearchPhaseExecutionException(phaseName, msg, null, ShardSearchFailure.EMPTY_ARRAY);
             }
         }