Andrew McGilvray added a comment - 2019-07-09 00:38 Downgrade to 3.2 fixes the issue.

Rita S added a comment - 2019-08-01 15:53 How do I downgrade the plugin, I don't see the downgrade button.

Andrew McGilvray added a comment - 2019-08-02 00:43 Are you in the "Installed" tab?

Felipe Leite added a comment - 2019-09-04 01:42 Thanks Andrew. I did that. but the idea was publish here to get fixed.

tsondergaard added a comment - 2019-09-10 08:39 I am seeing the same problem and downgrading to 3.2 does indeed solve the problem.

Filipe Roque added a comment - 2019-09-23 16:00 I wasted some time with this bug. From what I can tell, the bug was introduced with commit 0a9e67654a0f072601fb3a24d420c3c09ebfd843 , when upgrading jenkins.version property from 2.60.3 to 2.138.4. It happens because of commit ba33bd67cdaef87aba8a4e95dca8dcf108a7d73f  , in 2.138.2, which added an interface StaplerProxy to class Run . This interface defines a method Object getTarget() with an implementation in class Run . The Promotion class, which derives from Run , also has a method getTarget but with return type AbstractBuild<?,?> , so a synthetic method, with return type Object, is created by the compiler which invokes AbstractBuild<?,?> getTarget().   javap -v ./promoted-builds-2.138.2/WEB-INF/lib/promoted-builds/hudson/plugins/promoted_builds/Promotion.class public hudson.model.AbstractBuild<?, ?> getRootBuild(); descriptor: ()Lhudson/model/AbstractBuild; flags: (0x0001) ACC_PUBLIC Code: stack=1, locals=1, args_size=1 0: aload_0 1: invokevirtual #9 // Method getTarget:()Lhudson/model/AbstractBuild; 4: invokevirtual #10 // Method hudson/model/AbstractBuild.getRootBuild:()Lhudson/model/AbstractBuild; 7: areturn LineNumberTable: line 93: 0 LocalVariableTable: Start Length Slot Name Signature 0 8 0 this Lhudson/plugins/promoted_builds/Promotion; Signature: #185 // ()Lhudson/model/AbstractBuild<**>;   Renaming AbstractBuild<?,?> getTarget()   to AbstractBuild<?,?> getTarget2() fixes the bug, but I have no idea of its impacts because of the @Exported annotation. Note: the new Object getTarget() method in Run as an annotation @Restricted(NoExternalUse.class)   but I don't understand its meaning.    

Daniel Beck added a comment - 2019-10-07 15:46 I proposed a PR fixing this as JENKINS-59600 so closing this as a duplicate of that later issue. FWIW the previous comment's analysis appears correct and that's essentially what my fix does (while keeping the remote API the same).

Oleg Nenashev added a comment - 2019-10-08 00:12 Thanks to danielbeck , the fix was released in 3.4:  https://github.com/jenkinsci/promoted-builds-plugin/releases/tag/promoted-builds-3.4