Issued JIRA ticket 3511 to make it referable in other discussions. [1] [1] https://issues.apache.org/jira/browse/FLINK-3511
On Thu, Feb 25, 2016 at 3:36 PM, Márton Balassi <balassi.mar...@gmail.com> wrote: > Recent changes to the build [1] where many libraries got their core > dependencies (the ones included in the flink-dist fat jar) moved to the > provided scope. > > The reasoning was that when submitting to the Flink cluster the > application already has these dependencies, while when a user writes a > program against these libraries she will include the core dependencies > explicitly anyway. > > There is one other case of usage however, namely when someone is trying to > run an application defined in these libraries depending on the core jars. > To give an example if you were to run the Gelly ConnectedComponents example > [2] from an IDE after importing Flink (or running with java -jar without > including the flink fat jar in the classpath) you would receive the > following class not found exception as per the current master: > > Exception in thread "main" java.lang.NoClassDefFoundError: > org/apache/flink/api/common/ProgramDescription > at java.lang.ClassLoader.defineClass1(Native Method) > at java.lang.ClassLoader.defineClass(ClassLoader.java:760) > at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142) > at java.net.URLClassLoader.defineClass(URLClassLoader.java:467) > at java.net.URLClassLoader.access$100(URLClassLoader.java:73) > at java.net.URLClassLoader$1.run(URLClassLoader.java:368) > at java.net.URLClassLoader$1.run(URLClassLoader.java:362) > at java.security.AccessController.doPrivileged(Native Method) > at java.net.URLClassLoader.findClass(URLClassLoader.java:361) > at java.lang.ClassLoader.loadClass(ClassLoader.java:424) > at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:331) > at java.lang.ClassLoader.loadClass(ClassLoader.java:357) > at java.lang.Class.forName0(Native Method) > at java.lang.Class.forName(Class.java:264) > at com.intellij.rt.execution.application.AppMain.main(AppMain.java:122) > > Where the class missing in runtime is in flink-core, a transitive > dependency of the jars moved to the provided scope. > > Funny thing is we have tests in place to run our examples, but those add > test scope dependencies re-adding the missing classes, so it is never > discovered. > > I agree with the original purpose of PR #1683, but also think that the > current state makes for very inconvenient user experience. > > I would like to open a discussion on how and when to resolve the issue > given the release of 1.0.0. > > 1. Is it a release blocker? > 2. Should the change be reverted or is it sufficient to have proper > documentation around it? Maybe a maven profile for explicitly for > developing Flink without the provided scope? > > Note that the issue was originally reported by Gábor Gévay. > > [1] https://github.com/apache/flink/pull/1683 > [2] > https://github.com/apache/flink/blob/master/flink-libraries/flink-gelly/src/main/java/org/apache/flink/graph/example/ConnectedComponents.java > > Best, > > Marton >
