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
@Override
                    public void execute() {
                        emit("foo");
                    }
                };
            }
        };
    }
    public void testLegacyField() throws Exception {
        
        MapperService service = createMapperService(Version.fromString("5.0.0"), Settings.EMPTY, () -> false, mapping(b -> {
            b.startObject("mykeyw");
            b.field("type", "keyword");
            b.field("normalizer", "unknown-normalizer");
            b.endObject();
        }));
        assertThat(service.fieldType("mykeyw"), instanceOf(KeywordFieldMapper.KeywordFieldType.class));
        assertEquals(Lucene.KEYWORD_ANALYZER, ((KeywordFieldMapper.KeywordFieldType) service.fieldType("mykeyw")).normalizer());
        
        merge(service, mapping(b -> {
            b.startObject("mykeyw");
            b.field("type", "keyword");
            b.field("normalizer", "lowercase");
            b.endObject();
        }));
        assertThat(service.fieldType("mykeyw"), instanceOf(KeywordFieldMapper.KeywordFieldType.class));
        assertNotEquals(Lucene.KEYWORD_ANALYZER, ((KeywordFieldMapper.KeywordFieldType) service.fieldType("mykeyw")).normalizer());
    }
}