ppkarwasz commented on PR #2155: URL: https://github.com/apache/zookeeper/pull/2155#issuecomment-2048289428
> > The meaning is pretty much up to each developer to interpret. I interpret `provided` as "we don't bundle Logback, but you **need** it for Zookeeper to run". Regarding `optional` I interpret it as "some Zookeeper features only work with Logback" (a Logback appender maybe?). > > Maven [actually defines](https://maven.apache.org/guides/introduction/introduction-to-optional-and-excludes-dependencies.html) the [meaning of these](https://maven.apache.org/guides/introduction/introduction-to-dependency-mechanism.html). I think your interpretation is pretty much correct, because it aligns with these definitions, but I don't think it's as subjective as you suggest. These definitions are what developers use to implement behavioral differences. Inside the Zookeeper project I agree: there are behavioral differences. But if Zookeeper is used as a dependency in another project, the differences fade. >> I think the message that should be sent to users is "Zookeeper prefers/recommends Logback, but it will work with whatever SLF4J implementation your provide him". > > I would say "happens to use" rather than "prefers/recommends", but yes, I think that message is basically the right message. But I think that message can be communicated with optional, and a basic understanding of Java logging frameworks. Yes, it makes sense. I might steal your interpretation and add an optional runtime dependency on Logback to `log4j-to-slf4j`, although the proposal to make Log4j Core an optional runtime dependency of `log4j-slf4j2-impl` in [LOG4J2-3601](https://issues.apache.org/jira/browse/LOG4J2-3601) was not met with a big applause. :stuck_out_tongue_winking_eye: [Disclaimer: I understand that these examples give the user only one serious choice of logging backend, while Zookeeper has two] > > Inside the Zookeeper project their usefulness is also somehow limited: the Maven Compiler and Surefire plugins will use them, but the Maven Assembly plugin will not package them in the `tar.gz` archive. > > So the only difference between runtime `optional` and `test` is that Logback is available at compilation time. This **is not** an advantage: if Zookeeper fails to compile without Logback, it means that it references some Logback-specific classes. > > This is not true. There's actually no difference here. If it's marked optional alone, but still in the default "compile" scope, it will be available at compilation time. However, if it's marked "runtime", it is not available at compilation time... only test. That's why "optional" is frequently used in conjunction with "runtime" scope. So, there's actually no difference in behavior between these... it really just comes down to communicating intent. Sorry, I was thinking `compile optional`. Thanks for correcting me. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: notifications-unsubscr...@zookeeper.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org
