[JENKINS-26107] StepContext.hasBody implementation.

pom.xml

@@ -69,7 +69,7 @@
         <dependency>
             <groupId>${project.groupId}</groupId>
             <artifactId>workflow-step-api</artifactId>
-            <version>1.15</version>
+            <version>2.1-SNAPSHOT</version>
         </dependency>
         <dependency>
             <groupId>${project.groupId}</groupId>

src/main/java/org/jenkinsci/plugins/workflow/cps/CpsStepContext.java

@@ -152,7 +152,7 @@
      *
      * This is the implicit closure block passed to the step invocation.
      */
-    private BodyReference body;
+    private @CheckForNull BodyReference body;
 
     private final int threadId;
 
@@ -174,12 +174,12 @@
     private transient volatile boolean loadingThreadGroup;
 
     @CpsVmThreadOnly
-    CpsStepContext(StepDescriptor step, CpsThread thread, FlowExecutionOwner executionRef, FlowNode node, Closure body) {
+    CpsStepContext(StepDescriptor step, CpsThread thread, FlowExecutionOwner executionRef, FlowNode node, @CheckForNull Closure body) {
         this.threadId = thread.id;
         this.executionRef = executionRef;
         this.id = node.getId();
         this.node = node;
-        this.body = thread.group.export(body);
+        this.body = body != null ? thread.group.export(body) : null;
         this.stepDescriptorId = step.getId();
     }
 
@@ -269,14 +269,19 @@ public String getDisplayName() {
         }
     }
 
+    @Override public boolean hasBody() {
+        return body != null;
+    }
+
     @Override
     public CpsBodyInvoker newBodyInvoker() {
+        if (body == null) {
+            throw new IllegalStateException("There is no body to invoke");
+        }
         return newBodyInvoker(body);
     }
 
-    public CpsBodyInvoker newBodyInvoker(BodyReference body) {
-        if (body==null)
-            throw new IllegalStateException("There's no body to invoke");
+    public @Nonnull CpsBodyInvoker newBodyInvoker(@Nonnull BodyReference body) {
         return new CpsBodyInvoker(this,body);
     }
 

src/main/java/org/jenkinsci/plugins/workflow/cps/CpsThreadGroup.java

@@ -60,6 +60,7 @@
 import java.util.logging.Logger;
 
 import static java.util.logging.Level.*;
+import javax.annotation.Nonnull;
 import org.codehaus.mojo.animal_sniffer.IgnoreJRERequirement;
 import static org.jenkinsci.plugins.workflow.cps.CpsFlowExecution.*;
 import static org.jenkinsci.plugins.workflow.cps.persistence.PersistenceContext.*;
@@ -149,17 +150,15 @@ public CpsThread getThread(int id) {
     }
 
     @CpsVmThreadOnly("root")
-    public BodyReference export(Closure body) {
+    public @Nonnull BodyReference export(@Nonnull Closure body) {
         assertVmThread();
-        if (body==null)     return null;
         int id = iota++;
         closures.put(id, body);
         return new StaticBodyReference(id,body);
     }
 
     @CpsVmThreadOnly("root")
-    public BodyReference export(final Script body) {
-        if (body==null)     return null;
+    public @Nonnull BodyReference export(@Nonnull final Script body) {
         return export(new Closure(null) {
             @Override
             public Object call() {