2.0.7 release preparations

[akarnokd]

Version 2.0.7 - March 7, 2017 (Maven)

Reactive-Streams compliance

Related issue 5110, related pull 5112.

RxJava 2's Flowable was designed with Reactive-Streams compliance in mind but didn't follow all rules to the letter. A temporary workaround was the introduction of the strict() operator to enable full compliance. Unfortunately, according to the clarified stance from the specification leads, implementors of Publisher must honor the specification (despite its shortcomings) without excuses or workarounds.

Honoring the specification adds a per-item cost of two atomic increments, manifesting in between the Flowable and an arbitrary Reactive-Streams compliant org.reactivestreams.Subscriber. See Pull 5115 for the benchmark comparison.

Starting from 2.0.7, the Flowable.subscribe(org.reactivestreams.Subscriber) now follows the spec by wrapping via the StrictSubscriber of the strict() operator unless the consuming instance implements a new interface specific to RxJava 2: FlowableSubscriber.

The FlowableSubscriber extends org.reactivestreams.Subscriber but doesn't add any new methods and only overrides four of the textual rules of the specification to enable a relaxed operation within RxJava 2. All internal operators have been converted to use this new interface and thus don't have suffer the per-item overhead required by the specification, including the standard DisposableSubscriber, TestSubscriber and ResourceSubscriber. The lambda-based subscribe() operators were also retrofitted.

If you were implementing a Subscriber (directly or anonymously), you may want to change the interface to FlowableSubscriber. In order to avoid some of the runtime checks when subscribing to Flowable the new subscribe(FlowableSubscriber) has been introduced.

Note that the other reactive base types, Observable, Single, Maybe and Completable are not affected as these were never intended to implement the Reactive-Streams specification (they were only inspired by the spec and are RxJava 2 only to begin with).

API enhancements

• Pull 5117: Add ParallelFlowable.sequentialDelayError.
• Pull 5137: Add TestSubscriber.withTag.
• Pull 5140: Fix timed replay-like components replaying outdated items.
• Pull 5155: Add TestSubscriber.awaitCount, assertTimeout & assertNoTimeout, improve assertion error message

API deprecations

• Pull 5112: Flowable.strict() deprecated and will be removed in 2.1.0 - the default Flowable behavior is now strict.

Bugfixes

• Pull 5101: Fix Maybe.concat() subscribe-after-cancel, verify others.
• Pull 5103: Fix doOnSubscribe signalling UndeliverableException instead of onError.
• Pull 5106: Fix window(time, size) not completing windows on timeout.
• Pull 5114: Fix Observable.combineLatest to dispose eagerly.
• Pull 5121: Fix Observable.zip to dispose eagerly.
• Pull 5133: Fix flatMap not cancelling the upstream eagerly.
• Pull 5136: Fix repeatWhen and retryWhen signatures.

Other

• Pull 5102: Added missing @NonNull attribute to Function7.
• Pull 5112: Flowable as a Publisher to be fully RS compliant.
• Pull 5127: Update javadoc of flatMap() overloads.
• Pull 5153: Java 9 compatibility fixes
• Pull 5156: Add @NonNull to the methods of Emitter

[akarnokd]

Closing via v2.0.7