The test class `KeywordFieldMapperTests` contains a switch statement with a branch that will never execute. The test uses a `between(x, y)` switch expression, but the `4` case is outside the randomised range. We need to fix this before #88739 can be merged. By "fix", I mean either remove the spurious case, or if we actually want it then extend the randomized range.
server/src/test/java/org/elasticsearch/index/mapper/KeywordFieldMapperTests.java
ParsedDocument doc = mapper.parse(source(b -> b.field("field", "1234")));
        IndexableField[] fields = doc.rootDoc().getFields("field");
        assertEquals(1, fields.length);
        assertEquals(IndexOptions.NONE, fields[0].fieldType().indexOptions());
        assertEquals(DocValuesType.SORTED_SET, fields[0].fieldType().docValuesType());
    }
    public void testDisableDocValues() throws IOException {
        DocumentMapper mapper = createDocumentMapper(fieldMapping(b -> b.field("type", "keyword").field("doc_values", false)));
        ParsedDocument doc = mapper.parse(source(b -> b.field("field", "1234")));
        IndexableField[] fields = doc.rootDoc().getFields("field");
        assertEquals(1, fields.length);
        assertEquals(DocValuesType.NONE, fields[0].fieldType().docValuesType());
    }
    public void testIndexOptions() throws IOException {
        DocumentMapper mapper = createDocumentMapper(fieldMapping(b -> b.field("type", "keyword").field("index_options", "freqs")));
        ParsedDocument doc = mapper.parse(source(b -> b.field("field", "1234")));
        IndexableField[] fields = doc.rootDoc().getFields("field");
        assertEquals(2, fields.length);
        assertEquals(IndexOptions.DOCS_AND_FREQS, fields[0].fieldType().indexOptions());
        for (String indexOptions : Arrays.asList("positions", "offsets")) {
            MapperParsingException e = expectThrows(
                MapperParsingException.class,
                () -> createMapperService(fieldMapping(b -> b.field("type", "keyword").field("index_options", indexOptions)))
            );
            assertThat(
                e.getMessage(),
                containsString("Unknown value [" + indexOptions + "] for field [index_options] - accepted values are [docs, freqs]")
            );
        }
    }