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
assertEquals(0, fields.length);
        doc = mapper.parse(source(b -> b.field("field", "elasticsearch")));
        fields = doc.rootDoc().getFields("field");
        assertEquals(0, fields.length);
        fields = doc.rootDoc().getFields("_ignored");
        assertEquals(1, fields.length);
        assertEquals("field", fields[0].stringValue());
    }
    public void testNullValue() throws IOException {
        DocumentMapper mapper = createDocumentMapper(fieldMapping(this::minimalMapping));
        ParsedDocument doc = mapper.parse(source(b -> b.nullField("field")));
        assertArrayEquals(new IndexableField[0], doc.rootDoc().getFields("field"));
        mapper = createDocumentMapper(fieldMapping(b -> b.field("type", "keyword").field("null_value", "uri")));
        doc = mapper.parse(source(b -> {}));
        IndexableField[] fields = doc.rootDoc().getFields("field");
        assertEquals(0, fields.length);
        doc = mapper.parse(source(b -> b.nullField("field")));
        fields = doc.rootDoc().getFields("field");
        assertEquals(2, fields.length);
        assertEquals(new BytesRef("uri"), fields[0].binaryValue());
    }
    public void testEnableStore() throws IOException {
        DocumentMapper mapper = createDocumentMapper(fieldMapping(b -> b.field("type", "keyword").field("store", true)));
        ParsedDocument doc = mapper.parse(source(b -> b.field("field", "1234")));
        IndexableField[] fields = doc.rootDoc().getFields("field");
        assertEquals(2, fields.length);
        assertTrue(fields[0].fieldType().stored());
    }
    public void testDisableIndex() throws IOException {
        DocumentMapper mapper = createDocumentMapper(fieldMapping(b -> b.field("type", "keyword").field("index", false)));