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
{
                b.startObject();
                {
                    b.startArray("array_name").value("inner_field_first").value("inner_field_second").endArray();
                }
                b.endObject();
            }
            b.endArray();
        })));
        assertEquals(
            "failed to parse field [field] of type [keyword] in document with id '1'. "
                + "Preview of field's value: '{array_name=[inner_field_first, inner_field_second]}'",
            ex.getMessage()
        );
    }
    public void testParsesKeywordNullStrict() throws IOException {
        DocumentMapper defaultMapper = createDocumentMapper(fieldMapping(this::minimalMapping));
        Exception e = expectThrows(
            MapperParsingException.class,
            () -> defaultMapper.parse(source(b -> b.startObject("field").nullField("field_name").endObject()))
        );
        assertEquals(
            "failed to parse field [field] of type [keyword] in document with id '1'. " + "Preview of field's value: '{field_name=null}'",
            e.getMessage()
        );
    }
    public void testUpdateNormalizer() throws IOException {
        MapperService mapperService = createMapperService(fieldMapping(b -> b.field("type", "keyword").field("normalizer", "lowercase")));
        IllegalArgumentException e = expectThrows(
            IllegalArgumentException.class,