Beyond just formally declaring the current behavior, this revision actually enforces non-null behavior in selected signatures now, not tolerating null values anymore when not explicitly documented. It also changes some utility methods with historic null-in/null-out tolerance towards enforced non-null return values, making them a proper citizen in non-null assignments.
Some issues are left as to-do: in particular a thorough revision of spring-test, and a few tests with unclear failures (ignored as "TODO: NULLABLE") to be sorted out in a follow-up commit.
Issue: SPR-15540
This commit introduces 2 new @Nullable and @NonNullApi
annotations that leverage JSR 305 (dormant but available via
Findbugs jsr305 dependency and already used by libraries
like OkHttp) meta-annotations to specify explicitly
null-safety of Spring Framework parameters and return values.
In order to avoid adding too much annotations, the
default is set at package level with @NonNullApi and
@Nullable annotations are added when needed at parameter or
return value level. These annotations are intended to be used
on Spring Framework itself but also by other Spring projects.
@Nullable annotations have been introduced based on Javadoc
and search of patterns like "return null;". It is expected that
nullability of Spring Framework API will be polished with
complementary commits.
In practice, this will make the whole Spring Framework API
null-safe for Kotlin projects (when KT-10942 will be fixed)
since Kotlin will be able to leverage these annotations to
know if a parameter or a return value is nullable or not. But
this is also useful for Java developers as well since IntelliJ
IDEA, for example, also understands these annotations to
generate warnings when unsafe nullable usages are detected.
Issue: SPR-15540
Failures in JettySockJsIntegrationTests after the upgrade to 9.4 were
hidden due to the PERFORMANCE test group but were failing on the CI
performance build with IllegalStateException inside Jetty on
"Failure find the required ServletContext attribute
org.eclipse.jetty.util.DecoratedObjectFactory".
Rename classes not specific to Tomcat:
TomcatWebSocketSession -> StandardWebSocketSession
TomcatWebSocketHandlerAdapter -> StandardWebSocketHandlerAdapter
WebSocketSessionSupport is renamed to AbstractWebSocketSession since it
actually is a WebSocketSession and pre-implements a number of methods.
ServerEndpointRegistration is now package private (mainly for use in
upgrade strategies) and renamed to DefaultServerEndpointConfig.
This commit makes it possible for a ChannelInterceptor to override the
user header in a Spring Message that contains a STOMP CONNECT frame.
After the message is sent, the updated user header is observed and
saved to be associated with session thereafter.
Issue: SPR-14690
Due to a few changes in `WebSocketServerFactory` and `Session` API, our
`JettyRequestUpgradeStrategy` and `JettyWebSocketSession` needed to
adapt. As of 9.3.15+ and 9.4.0+, some reflection is required to support
previous versions.
Spring 5.0 supports Jetty 9.3 and 9.4.
Issue: SPR-14940
When processing a "close" notification from the server make an effort
to cancel any outstanding heartbeat but avoid going as far as acquiring
the responseLock since the server itself may already hold a lock of its
own leading to a potential deadlock.
The heartbeat task is now also further protected with an isClosed()
check in case the heartbeat does not get cancelled in a concurrent
scenario.
Issue: SPR-14917
This commits adds a validation check whether the SockJS session type
matches the transport type and rejects requests for which they
don't match.
Issue: SPR-14867
Create an explicit heartbeat task with an experiration flag so that
it can be cancelled reliably vs relying on the ScheduledFutureTask
cancel method which may return true even if the task is already
running.
Issue: SPR-14356
Juergen Hoeller
Sebastien Deleuze
Rossen Stoyanchev
Sam Brannen
Brian Clozel
Christoph Dreis