Polishing.

Enforce non-nullability of serializers when actually using these.

See: #3223
Original pull request: #3244

Author: mp911de

src/main/java/org/springframework/data/redis/core/AbstractOperations.java

@@ -51,6 +51,7 @@
  * @author Denis Zavedeev
  */
 @NullUnmarked
+@SuppressWarnings("rawtypes")
 abstract class AbstractOperations<K, V> {
 
 	// utility methods for the template internal methods
@@ -93,22 +94,70 @@ ValueDeserializingRedisCallback valueCallbackFor(Object key, BiFunction<RedisCon
 		return new FunctionalValueDeserializingRedisCallback(key, function);
 	}
 
+	@Nullable
 	RedisSerializer keySerializer() {
 		return template.getKeySerializer();
 	}
 
+	RedisSerializer requiredKeySerializer() {
+
+		RedisSerializer serializer = keySerializer();
+
+		if (serializer == null) {
+			throw new IllegalStateException("No key serializer configured");
+		}
+
+		return serializer;
+	}
+
+	@Nullable
 	RedisSerializer valueSerializer() {
 		return template.getValueSerializer();
 	}
 
+	RedisSerializer requiredValueSerializer() {
+
+		RedisSerializer serializer = valueSerializer();
+
+		if (serializer == null) {
+			throw new IllegalStateException("No value serializer configured");
+		}
+
+		return serializer;
+	}
+
+	@Nullable
 	RedisSerializer hashKeySerializer() {
 		return template.getHashKeySerializer();
 	}
 
+	RedisSerializer requiredHashKeySerializer() {
+
+		RedisSerializer serializer = hashKeySerializer();
+
+		if (serializer == null) {
+			throw new IllegalStateException("No hash key serializer configured");
+		}
+
+		return serializer;
+	}
+
+	@Nullable
 	RedisSerializer hashValueSerializer() {
 		return template.getHashValueSerializer();
 	}
 
+	RedisSerializer requiredHashValueSerializer() {
+
+		RedisSerializer serializer = hashValueSerializer();
+
+		if (serializer == null) {
+			throw new IllegalStateException("No hash value serializer configured");
+		}
+
+		return serializer;
+	}
+
 	RedisSerializer stringSerializer() {
 		return template.getStringSerializer();
 	}
@@ -130,7 +179,7 @@ byte[] rawKey(@NonNull Object key) {
 			return bytes;
 		}
 
-		return keySerializer().serialize(key);
+		return requiredKeySerializer().serialize(key);
 	}
 
 	@SuppressWarnings("unchecked")
@@ -145,7 +194,7 @@ byte[] rawValue(Object value) {
 			return bytes;
 		}
 
-		return valueSerializer().serialize(value);
+		return requiredValueSerializer().serialize(value);
 	}
 
 	byte[][] rawValues(Object... values) {
@@ -309,23 +358,23 @@ <T> Set<T> deserializeHashKeys(Set<byte[]> rawKeys) {
 		if (hashKeySerializer() == null) {
 			return (Set<T>) rawKeys;
 		}
-		return SerializationUtils.deserialize(rawKeys, hashKeySerializer());
+		return SerializationUtils.deserialize(rawKeys, requiredHashKeySerializer());
 	}
 
 	@SuppressWarnings("unchecked")
 	<T> List<T> deserializeHashKeys(List<byte[]> rawKeys) {
 		if (hashKeySerializer() == null) {
 			return (List<T>) rawKeys;
 		}
-		return SerializationUtils.deserialize(rawKeys, hashKeySerializer());
+		return SerializationUtils.deserialize(rawKeys, requiredHashKeySerializer());
 	}
 
 	@SuppressWarnings("unchecked")
 	<T> List<T> deserializeHashValues(List<byte[]> rawValues) {
 		if (hashValueSerializer() == null) {
 			return (List<T>) rawValues;
 		}
-		return SerializationUtils.deserialize(rawValues, hashValueSerializer());
+		return SerializationUtils.deserialize(rawValues, requiredHashValueSerializer());
 	}
 
 	@SuppressWarnings("unchecked")
@@ -350,7 +399,7 @@ K deserializeKey(byte[] value) {
 		if (keySerializer() == null) {
 			return (K) value;
 		}
-		return (K) keySerializer().deserialize(value);
+		return (K) requiredKeySerializer().deserialize(value);
 	}
 
 	/**
@@ -375,7 +424,7 @@ V deserializeValue(byte[] value) {
 		if (valueSerializer() == null) {
 			return (V) value;
 		}
-		return (V) valueSerializer().deserialize(value);
+		return (V) requiredValueSerializer().deserialize(value);
 	}
 
 	String deserializeString(byte[] value) {
@@ -387,15 +436,15 @@ <HK> HK deserializeHashKey(byte[] value) {
 		if (hashKeySerializer() == null) {
 			return (HK) value;
 		}
-		return (HK) hashKeySerializer().deserialize(value);
+		return (HK) requiredHashKeySerializer().deserialize(value);
 	}
 
 	@SuppressWarnings("unchecked")
 	<HV> HV deserializeHashValue(byte[] value) {
 		if (hashValueSerializer() == null) {
 			return (HV) value;
 		}
-		return (HV) hashValueSerializer().deserialize(value);
+		return (HV) requiredHashValueSerializer().deserialize(value);
 	}
 
 	/**

src/main/java/org/springframework/data/redis/core/DefaultStreamOperations.java

@@ -340,7 +340,7 @@ public MapRecord<K, HK, HV> deserializeRecord(@NonNull ByteRecord record) {
 	}
 
 	protected byte[] serializeHashValueIfRequires(HV value) {
-		return hashValueSerializerPresent() ? serialize(value, hashValueSerializer())
+		return hashValueSerializerPresent() ? serialize(value, requiredHashValueSerializer())
 				: objectMapper.getConversionService().convert(value, byte[].class);
 	}
 

src/main/java/org/springframework/data/redis/core/RedisOperations.java

@@ -785,25 +785,25 @@ <T, S> List<T> sort(SortQuery<@NonNull K> query, @NonNull BulkMapper<T, S> bulkM
 	/**
 	 * @return the key {@link RedisSerializer}.
 	 */
-	@NonNull
+	@Nullable
 	RedisSerializer<?> getKeySerializer();
 
 	/**
 	 * @return the value {@link RedisSerializer}.
 	 */
-	@NonNull
+	@Nullable
 	RedisSerializer<?> getValueSerializer();
 
 	/**
 	 * @return the hash key {@link RedisSerializer}.
 	 */
-	@NonNull
+	@Nullable
 	RedisSerializer<?> getHashKeySerializer();
 
 	/**
 	 * @return the hash value {@link RedisSerializer}.
 	 */
-	@NonNull
+	@Nullable
 	RedisSerializer<?> getHashValueSerializer();
 
 }

src/main/java/org/springframework/data/redis/core/script/DefaultScriptExecutor.java

@@ -132,7 +132,7 @@ protected <T> T deserializeResult(RedisSerializer<T> resultSerializer, Object re
 	}
 
 	@SuppressWarnings("rawtypes")
-	protected RedisSerializer keySerializer() {
+	protected @Nullable RedisSerializer keySerializer() {
 		return template.getKeySerializer();
 	}
 

src/main/java/org/springframework/data/redis/serializer/SerializationUtils.java

@@ -27,6 +27,8 @@
 import org.jspecify.annotations.Nullable;
 import org.springframework.core.CollectionFactory;
 import org.springframework.lang.Contract;
+import org.springframework.util.Assert;
+import org.springframework.util.CollectionUtils;
 
 /**
  * Utility class with various serialization-related methods.
@@ -46,10 +48,12 @@ static boolean isEmpty(byte @Nullable [] data) {
 	static <T extends Collection<?>> T deserializeValues(@Nullable Collection<byte[]> rawValues, Class<T> type,
 			@Nullable RedisSerializer<?> redisSerializer) {
 		// connection in pipeline/multi mode
-		if (rawValues == null) {
+		if (CollectionUtils.isEmpty(rawValues)) {
 			return (T) CollectionFactory.createCollection(type, 0);
 		}
 
+		Assert.notNull(redisSerializer, "RedisSerializer must not be null");
+
 		Collection<Object> values = (List.class.isAssignableFrom(type) ? new ArrayList<>(rawValues.size())
 				: new LinkedHashSet<>(rawValues.size()));
 		for (byte[] bs : rawValues) {
@@ -79,9 +83,12 @@ public static <T> Collection<T> deserialize(@Nullable Collection<byte[]> rawValu
 	public static <T> Map<T, @Nullable T> deserialize(@Nullable Map<byte[], byte[]> rawValues,
 			RedisSerializer<T> redisSerializer) {
 
-		if (rawValues == null) {
+		if (CollectionUtils.isEmpty(rawValues)) {
 			return Collections.emptyMap();
 		}
+
+		Assert.notNull(redisSerializer, "RedisSerializer must not be null");
+
 		Map<T, @Nullable T> ret = new LinkedHashMap<>(rawValues.size());
 		for (Map.Entry<byte[], byte[]> entry : rawValues.entrySet()) {
 			ret.put(redisSerializer.deserialize(entry.getKey()), redisSerializer.deserialize(entry.getValue()));
@@ -92,7 +99,7 @@ public static <T> Collection<T> deserialize(@Nullable Collection<byte[]> rawValu
 	public static <HK, HV> Map<HK, HV> deserialize(@Nullable Map<byte[], byte[]> rawValues,
 			@Nullable RedisSerializer<HK> hashKeySerializer, @Nullable RedisSerializer<HV> hashValueSerializer) {
 
-		if (rawValues == null) {
+		if (CollectionUtils.isEmpty(rawValues)) {
 			return Collections.emptyMap();
 		}
 

src/test/java/org/springframework/data/redis/core/DefaultValueOperationsIntegrationTests.java

@@ -154,7 +154,7 @@ void testDecrementByLong() {
 		assertThat(valueOps.get(key)).isEqualTo((Long) value - 5);
 	}
 
-	@Test
+	@Test // GH-3223
 	void testMultiGet() {
 
 		K key1 = keyFactory.instance();