[jira] [Commented] (GROOVY-11823) Check whether inserted metaprogramming methods in a static nested class override methods in a superclass and fail, warn, or make it work

["Eric Milles (Jira)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/GROOVY-11823?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=18047943#comment-18047943 ] 

Eric Milles commented on GROOVY-11823:
--------------------------------------

Given a setup like:
{code:groovy}
class Upper {
  def propertyMissing(String name) {
    if (name == 'fizz') return 'buzz'
    throw new MissingPropertyException(name, getClass())
  }
}
class Outer {
  static class Inner extends Upper {
  }
}

assert new Outer.Inner().fizz == 'buzz'
{code}

In order for the property "fizz" to be available from an inner class or enum, the compiler-supplied MOP methods would need to delegate to super class methods as part of their implementation.

> Check whether inserted metaprogramming methods in a static nested class override methods in a superclass and fail, warn, or make it work
> ----------------------------------------------------------------------------------------------------------------------------------------
>
>                 Key: GROOVY-11823
>                 URL: https://issues.apache.org/jira/browse/GROOVY-11823
>             Project: Groovy
>          Issue Type: Improvement
>    Affects Versions: 4.0.29
>            Reporter: Björn Kautler
>            Priority: Major
>
> Given the following code:
> {code:groovy}@Grab('org.apache.groovy.geb:geb-spock:8.0.1')
> import geb.spock.GebSpec
> class Foo {
>   static class Bar extends GebSpec {
>     def bar() {
>       println(browser.driver)
>       println(driver)
>       expect: true
>     }
>   }
> }{code}
> and assuming that either GROOVY-11822 was fixed or Geb changed to use {{void}} as return type so that the code actually compiles.
> Due to the Groovy compiler overwriting the {{propertyMissing}} and {{methodMissing}} methods, the {{println(driver)}} line no longer works, outside a static nested class it works as intended.
> This behavior is silent and at first very confusing to a user.
> One option - though an imho very bad one - would be to fail the build just like when you try to have any of those methods in your code directly.
> But, e.g. in this case, you might still be able to use the superclass, you here just have to be a bit more explicit and use {{browser.}} instead of the meatprogramming magic, so it would be sad if the solution is to fail the build.
> Maybe other two options would either a prominent compiler warning if those methods override ones from a superclass so that you at least have a chance to get aware of the problem,
> or maybe it could even be made in a way that the compiler-inserted methods consider the superclass methods by calling them at an appropriate place.
> The last solution would maybe be optimal as it would then work as expected, unless there are details I don't know why this cannot work.
> If some class does depend on those methods not being overwritten and not just provide convenience like {{GebSpec}}, they can probably also declare the methods {{final}} to prevent static nested subclasses being created.



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