1.x: add AnimalSniffer to the build process, fix and suppress violations

[akarnokd]

This PR adds the AnimalSniffer plugin to check for Java 6 API violations.

Related issue: #4067.

[akarnokd]

/cc @artem-zinnatullin @zsxwing @JakeWharton

[akarnokd]

Flaky tests:

rx.observers.TestSubscriberTest > testOnErrorCrashCountsDownLatch FAILED
    org.junit.runners.model.TestTimedOutException: test timed out after 1000 milliseconds
        at java.lang.ClassLoader.defineClass1(Native Method)
        at java.lang.ClassLoader.defineClass(ClassLoader.java:800)
        at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142)
        at java.net.URLClassLoader.defineClass(URLClassLoader.java:449)
        at java.net.URLClassLoader.access$100(URLClassLoader.java:71)
        at java.net.URLClassLoader$1.run(URLClassLoader.java:361)
        at java.net.URLClassLoader$1.run(URLClassLoader.java:355)
        at java.security.AccessController.doPrivileged(Native Method)
        at java.net.URLClassLoader.findClass(URLClassLoader.java:354)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:425)
        at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:308)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:358)
        at rx.observers.TestSubscriberTest.testOnErrorCrashCountsDownLatch(TestSubscriberTest.java:595)

rx.plugins.RxJavaPluginsTest > testOnNextValueCallsPlugin FAILED
    java.lang.RuntimeException: java.util.concurrent.TimeoutException
        at rx.observables.BlockingObservable.blockForSingle(BlockingObservable.java:463)
        at rx.observables.BlockingObservable.first(BlockingObservable.java:163)
        at rx.plugins.RxJavaPluginsTest.testOnNextValueCallsPlugin(RxJavaPluginsTest.java:228)
        Caused by:
        java.util.concurrent.TimeoutException

rx.subjects.BehaviorSubjectTest > testUnsubscriptionCase FAILED
    org.junit.runners.model.TestTimedOutException: test timed out after 1000 milliseconds
        at java.lang.ClassLoader.findBootstrapClass(Native Method)
        at java.lang.ClassLoader.findBootstrapClassOrNull(ClassLoader.java:1070)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:414)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:412)
        at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:308)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:358)
        at java.lang.Class.forName0(Native Method)
        at java.lang.Class.forName(Class.java:191)
        at org.mockito.internal.configuration.ClassPathLoader.loadConfiguration(ClassPathLoader.java:68)
        at org.mockito.internal.configuration.GlobalConfiguration.createConfig(GlobalConfiguration.java:38)
        at org.mockito.internal.configuration.GlobalConfiguration.<init>(GlobalConfiguration.java:32)
        at org.mockito.internal.configuration.GlobalConfiguration.validate(GlobalConfiguration.java:47)
        at org.mockito.internal.progress.MockingProgressImpl.validateMostStuff(MockingProgressImpl.java:81)
        at org.mockito.internal.progress.MockingProgressImpl.mockingStarted(MockingProgressImpl.java:116)
        at org.mockito.internal.progress.ThreadSafeMockingProgress.mockingStarted(ThreadSafeMockingProgress.java:72)
        at org.mockito.internal.MockitoCore.mock(MockitoCore.java:60)
        at org.mockito.Mockito.mock(Mockito.java:1285)
        at org.mockito.Mockito.mock(Mockito.java:1163)
        at rx.subjects.BehaviorSubjectTest.testUnsubscriptionCase(BehaviorSubjectTest.java:249)

[akarnokd]

To be merged after #4091 in case there is a conflict.

[codecov-io]

Current coverage is 80.28%

Merging #4092 into 1.x will increase coverage by 0.02%

@@                1.x      #4092   diff @@
==========================================
  Files           259        259          
  Lines         16821      16821          
  Methods           0          0          
  Messages          0          0          
  Branches       2554       2554          
==========================================
+ Hits          13500      13504     +4   
+ Misses         2408       2402     -6   
- Partials        913        915     +2   

Powered by Codecov. Last updated by afe3cb0...7da62c2

[artem-zinnatullin]

If possible please report an issue back to animalsniffer

[artem-zinnatullin]

Does it really fail the build if you try to use Java7+ APIs?

[akarnokd]

That AssertionError initialization did fail locally, but can't really post a PR that demonstrates failure, right?

[artem-zinnatullin]

Sure sure, I mean have you checked that it really fails build that we perform on CI in case of using Java7+ APIs? (you can execute commands from buildViaTravis.sh locally to check that).

[akarnokd]

https://travis-ci.org/ReactiveX/RxJava/builds/139755352#L209

[akarnokd]

That's annoying, we seem to get shot down by out-of-memory checkers, maybe due to extensive thread usage? Or we have a leak somewhere.

[artem-zinnatullin]

👍

I see ~similar instability of CI regarding memory usage in other projects I work on, solution I currently stick to is to divide build into separate steps like:

./gradlew --no-daemon clean
./gradlew --no-daemon assemble
./gradlew --no-daemon test
// etc

Either it's leak in Gradle (or some plugin) or CI under load gives us less memory.

[ZacSweers]

👍