Pull match_only_text fixes into main (elastic#130049) (elastic#130136)

This brings in the fixes from elastic#130020, with minor fixes to address review
nits from that PR.

Co-authored-by: Martijn van Groningen <[email protected]>

Author: jordan-powers

build-tools-internal/src/main/resources/checkstyle_suppressions.xml

@@ -37,6 +37,7 @@
   <suppress files="qa[/\\]rolling-upgrade[/\\]src[/\\]javaRestTest[/\\]java[/\\]org[/\\]elasticsearch[/\\]upgrades[/\\]TsdbIT.java" checks="LineLength" />
   <suppress files="qa[/\\]rolling-upgrade[/\\]src[/\\]javaRestTest[/\\]java[/\\]org[/\\]elasticsearch[/\\]upgrades[/\\]TsdbIndexingRollingUpgradeIT.java" checks="LineLength" />
   <suppress files="qa[/\\]rolling-upgrade[/\\]src[/\\]javaRestTest[/\\]java[/\\]org[/\\]elasticsearch[/\\]upgrades[/\\]LogsdbIndexingRollingUpgradeIT.java" checks="LineLength" />
+  <suppress files="plugin[/\\]logsdb[/\\]qa[/\\]rolling-upgrade[/\\]src[/\\]javaRestTest[/\\]java[/\\]org[/\\]elasticsearch[/\\]upgrades[/\\]MatchOnlyTextRollingUpgradeIT.java" checks="LineLength" />
 
   <!-- Gradle requires inputs to be seriablizable -->
   <suppress files="build-tools-internal[/\\]src[/\\]main[/\\]java[/\\]org[/\\]elasticsearch[/\\]gradle[/\\]internal[/\\]precommit[/\\]TestingConventionRule.java" checks="RegexpSinglelineJava" />

modules/mapper-extras/src/main/java/org/elasticsearch/index/mapper/extras/MatchOnlyTextFieldMapper.java

@@ -362,10 +362,38 @@ public Query phrasePrefixQuery(TokenStream stream, int slop, int maxExpansions,
             return toQuery(query, queryShardContext);
         }
 
+        private static class BytesFromMixedStringsBytesRefBlockLoader extends BlockStoredFieldsReader.StoredFieldsBlockLoader {
+            BytesFromMixedStringsBytesRefBlockLoader(String field) {
+                super(field);
+            }
+
+            @Override
+            public Builder builder(BlockFactory factory, int expectedCount) {
+                return factory.bytesRefs(expectedCount);
+            }
+
+            @Override
+            public RowStrideReader rowStrideReader(LeafReaderContext context) throws IOException {
+                return new BlockStoredFieldsReader.Bytes(field) {
+                    private final BytesRef scratch = new BytesRef();
+
+                    @Override
+                    protected BytesRef toBytesRef(Object v) {
+                        if (v instanceof BytesRef b) {
+                            return b;
+                        } else {
+                            assert v instanceof String;
+                            return BlockSourceReader.toBytesRef(scratch, v.toString());
+                        }
+                    }
+                };
+            }
+        }
+
         @Override
         public BlockLoader blockLoader(BlockLoaderContext blContext) {
             if (textFieldType.isSyntheticSource()) {
-                return new BlockStoredFieldsReader.BytesFromBytesRefsBlockLoader(storedFieldNameForSyntheticSource());
+                return new BytesFromMixedStringsBytesRefBlockLoader(storedFieldNameForSyntheticSource());
             }
             SourceValueFetcher fetcher = SourceValueFetcher.toString(blContext.sourcePaths(name()));
             // MatchOnlyText never has norms, so we have to use the field names field
@@ -386,7 +414,12 @@ public IndexFieldData.Builder fielddataBuilder(FieldDataContext fieldDataContext
                 ) {
                     @Override
                     protected BytesRef storedToBytesRef(Object stored) {
-                        return (BytesRef) stored;
+                        if (stored instanceof BytesRef storedBytes) {
+                            return storedBytes;
+                        } else {
+                            assert stored instanceof String;
+                            return new BytesRef(stored.toString());
+                        }
                     }
                 };
             }
@@ -477,7 +510,12 @@ protected SyntheticSourceSupport syntheticSourceSupport() {
             () -> new StringStoredFieldFieldLoader(fieldType().storedFieldNameForSyntheticSource(), fieldType().name(), leafName()) {
                 @Override
                 protected void write(XContentBuilder b, Object value) throws IOException {
-                    b.value(((BytesRef) value).utf8ToString());
+                    if (value instanceof BytesRef valueBytes) {
+                        b.value(valueBytes.utf8ToString());
+                    } else {
+                        assert value instanceof String;
+                        b.value(value.toString());
+                    }
                 }
             }
         );

modules/mapper-extras/src/test/java/org/elasticsearch/index/mapper/extras/MatchOnlyTextFieldMapperTests.java

@@ -10,6 +10,9 @@
 package org.elasticsearch.index.mapper.extras;
 
 import org.apache.lucene.analysis.TokenStream;
+import org.apache.lucene.document.Field;
+import org.apache.lucene.document.StoredField;
+import org.apache.lucene.document.StringField;
 import org.apache.lucene.index.DirectoryReader;
 import org.apache.lucene.index.DocValuesType;
 import org.apache.lucene.index.IndexOptions;
@@ -21,6 +24,7 @@
 import org.apache.lucene.tests.analysis.CannedTokenStream;
 import org.apache.lucene.tests.analysis.Token;
 import org.apache.lucene.tests.index.RandomIndexWriter;
+import org.apache.lucene.util.BytesRef;
 import org.elasticsearch.common.Strings;
 import org.elasticsearch.core.Tuple;
 import org.elasticsearch.index.IndexSettings;
@@ -350,4 +354,29 @@ public void testStoreParameterDefaultsSyntheticSourceTextFieldIsMultiField() thr
             assertThat(fields, empty());
         }
     }
+
+    public void testLoadSyntheticSourceFromStringOrBytesRef() throws IOException {
+        DocumentMapper mapper = createSytheticSourceMapperService(mapping(b -> {
+            b.startObject("field1").field("type", "match_only_text").endObject();
+            b.startObject("field2").field("type", "match_only_text").endObject();
+        })).documentMapper();
+        try (Directory directory = newDirectory()) {
+            RandomIndexWriter iw = indexWriterForSyntheticSource(directory);
+
+            LuceneDocument document = new LuceneDocument();
+            document.add(new StringField("field1", "foo", Field.Store.NO));
+            document.add(new StoredField("field1._original", "foo"));
+
+            document.add(new StringField("field2", "bar", Field.Store.NO));
+            document.add(new StoredField("field2._original", new BytesRef("bar")));
+
+            iw.addDocument(document);
+            iw.close();
+
+            try (DirectoryReader indexReader = wrapInMockESDirectoryReader(DirectoryReader.open(directory))) {
+                String syntheticSource = syntheticSource(mapper, null, indexReader, 0);
+                assertEquals("{\"field1\":\"foo\",\"field2\":\"bar\"}", syntheticSource);
+            }
+        }
+    }
 }

server/src/main/java/org/elasticsearch/index/mapper/BlockSourceReader.java

@@ -469,7 +469,7 @@ public String toString() {
     /**
      * Convert a {@link String} into a utf-8 {@link BytesRef}.
      */
-    static BytesRef toBytesRef(BytesRef scratch, String v) {
+    public static BytesRef toBytesRef(BytesRef scratch, String v) {
         int len = UnicodeUtil.maxUTF8Length(v.length());
         if (scratch.bytes.length < len) {
             scratch.bytes = new byte[len];

server/src/main/java/org/elasticsearch/index/mapper/BlockStoredFieldsReader.java

@@ -35,10 +35,10 @@ public boolean canReuse(int startingDocID) {
         return true;
     }
 
-    private abstract static class StoredFieldsBlockLoader implements BlockLoader {
+    public abstract static class StoredFieldsBlockLoader implements BlockLoader {
         protected final String field;
 
-        StoredFieldsBlockLoader(String field) {
+        public StoredFieldsBlockLoader(String field) {
             this.field = field;
         }
 
@@ -112,10 +112,10 @@ protected BytesRef toBytesRef(Object v) {
         }
     }
 
-    private abstract static class Bytes extends BlockStoredFieldsReader {
+    public abstract static class Bytes extends BlockStoredFieldsReader {
         private final String field;
 
-        Bytes(String field) {
+        public Bytes(String field) {
             this.field = field;
         }