Fix class loading problem with DevTools and Spring Session with Redis

Previously, when a session attribute that had been stored in Redis was
being deserialized, the app class loader would be used. This would
result in a ClassCastException if the attribute was an instance of a
class visible to the restart class loader.

This commit auto-configures Spring Session’s RedisTemplate to use a
custom deserializer that uses the restart class loader when
deserializing session attributes.

Closes gh-3805

spring-boot-devtools/pom.xml

@@ -54,6 +54,16 @@
 			<artifactId>spring-security-web</artifactId>
 			<optional>true</optional>
 		</dependency>
+		<dependency>
+			<groupId>org.springframework.data</groupId>
+			<artifactId>spring-data-redis</artifactId>
+			<optional>true</optional>
+		</dependency>
+		<dependency>
+			<groupId>org.springframework.session</groupId>
+			<artifactId>spring-session</artifactId>
+			<optional>true</optional>
+		</dependency>
 		<!-- Annotation processing -->
 		<dependency>
 			<groupId>org.springframework.boot</groupId>