[jira] [Created] (GROOVY-9352) Static compilation fails with NoClassDefFoundError

["Cédric Champeau (Jira)" <ji...@apache.org>]

Cédric Champeau created GROOVY-9352:
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             Summary: Static compilation fails with NoClassDefFoundError
                 Key: GROOVY-9352
                 URL: https://issues.apache.org/jira/browse/GROOVY-9352
             Project: Groovy
          Issue Type: Bug
          Components: Static compilation
    Affects Versions: 3.0.0-rc-2, 2.5.8
            Reporter: Cédric Champeau


The static compiler is trying to resolve classes which it shouldn't. Imagine the following scenario:

 
 * a project written in Java exposes class `A` which has a private method using `D` as a parameter
 * `D` is an _implementation_ dependency of `A`, meaning it's not exposed in its public API, so consumers of `A` should never require `D` to build against `A`
 * a project `B` written in Groovy consumes `A` and tries to call a _public_ method of `A`
 ** if the class is using `@CompileStatic`, compilation FAILS with a NoClassDefFoundError
 ** if the class doesn't use `@CompileStatic`, compilation passes as expected

The reason is that when we compile `B`, we only put on the compile classpath the _API_ dependencies of `A`. But Groovy breaks because when it inspects class `A`, it tries to load internal implementation details (private fields, methods) and as such fails.

This is a big problem because it effectively breaks the contract of API/implementation separation, and forces either the producer to declare `D` as an _implementation_ dependency, which it's not, or redeclare `D` as an implementation dependency of `B`, which it isn't either, just to make the compiler happy!

 

The Gradle build itself is suffering from this. This is not nice because it forces compilation of things we don't need, and forces us to redeclare dependencies that we shouldn't.

 

To reproduce, checkout this project: [https://github.com/melix/groovy-compiler-bug]

 

and run `./gradlew build`

 



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