GitSCM is marked as Serializable but can't be serialized because of GitSCM.extensions

[Réda Housni Alaoui]

Hi everyone,

I'd like to understand how am I supposed to handle GitSCM in a StepExecution.

Here is the interesting portion of the code : https://github.com/jenkinsci/git-push-plugin/blob/5c9525da6da7bed8fd70e8a45d62eafd1daad3f1/src/main/java/io/jenkins/plugins/git_push/GitPushStep.java#L71-L71

If I remove the transient modifier from the GitScm attribute, I will get java.io.NotSerializableException: hudson.util.DescribableList.

Is GitPushStep already doing that correctly? If yes, what are the consequences of this lack of serialization?

[Mark Waite]

GitSCM is not serializable.  It is correct to not attempt to serialize it.  Can you explain why you believe that you need to serialize it? 

[Réda Housni Alaoui]

Given GitScm exends GitSCMBackwardCompatibility and GitSCMBackwardCompatibility implements Serializable, I though it was expecting it to be serializable.

Therefore, I suppose I can't do better than https://github.com/jenkinsci/git-push-plugin/blob/5c9525da6da7bed8fd70e8a45d62eafd1daad3f1/src/main/java/io/jenkins/plugins/git_push/GitPushStep.java#L71-L71 ?

[Jesse Glick]

I guess the question is prompted by https://github.com/jenkinsci/git-push-plugin/blob/5c9525da6da7bed8fd70e8a45d62eafd1daad3f1/src/main/java/io/jenkins/plugins/git_push/GitPushStep.java#L109 which is odd because while `StepExecution` in general is `Serializable`, a `SynchronousNonBlockingStepExecution` does not need to be meaningfully serializable since it will just be aborted across a controller restart. In other words the `readObject` and `writeObject` methods are useless and could be deleted.

`GitPushStep` as a whole seems dubious anyway, since you can just write e.g.

withGit(…) {

  sh 'git push …'

}

(More realistically, the `git push` would be embedded in some larger script.)