[FIX JENKINS-40894] Restore unstableReturn in readResolve

(cherry picked from commit 93467c3f)

core/src/main/java/hudson/tasks/BatchFile.java

@@ -81,7 +81,9 @@ public class BatchFile extends CommandInterpreter {
     }
 
     private Object readResolve() throws ObjectStreamException {
-        return new BatchFile(command);
+        BatchFile batch = new BatchFile(command);
+        batch.setUnstableReturn(unstableReturn);
+        return batch;
     }
 
     @Extension @Symbol("batchFile")

core/src/main/java/hudson/tasks/Shell.java

@@ -125,7 +125,9 @@ public class Shell extends CommandInterpreter {
     }
 
     private Object readResolve() throws ObjectStreamException {
-        return new Shell(command);
+        Shell shell = new Shell(command);
+        shell.setUnstableReturn(unstableReturn);
+        return shell;
     }
 
     @Extension @Symbol("shell")

test/src/test/java/hudson/tasks/BatchFileTest.java

 package hudson.tasks;
 
+import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertNull;
 import static org.junit.Assume.assumeTrue;
 
@@ -16,6 +17,7 @@ import hudson.Launcher.ProcStarter;
 import hudson.Proc;
 import hudson.model.Result;
 import hudson.model.FreeStyleProject;
+import org.jvnet.hudson.test.recipes.LocalData;
 
 
 /**
@@ -148,4 +150,13 @@ public class BatchFileTest {
         /* Creating unstable=0 produces unstable=null */
         assertNull( createNewBatchTask("",0).getUnstableReturn() );
     }
+
+    @Issue("JENKINS-40894")
+    @Test
+    @LocalData
+    public void canLoadUnstableReturnFromDisk() throws Exception {
+        FreeStyleProject p = (FreeStyleProject) rule.jenkins.getItemByFullName("batch");
+        BatchFile batchFile = (BatchFile) p.getBuildersList().get(0);
+        assertEquals("unstable return", Integer.valueOf(1), batchFile.getUnstableReturn());
+    }
 }

test/src/test/java/hudson/tasks/ShellTest.java

@@ -27,6 +27,7 @@ import org.junit.Assume;
 import org.junit.Rule;
 import org.junit.Test;
 import org.jvnet.hudson.test.JenkinsRule;
+import org.jvnet.hudson.test.recipes.LocalData;
 
 /**
  * Tests for the Shell tasks class
@@ -190,4 +191,13 @@ public class ShellTest {
         assertNull( createNewShell("",0).getUnstableReturn() );
     }
 
+    @Issue("JENKINS-40894")
+    @Test
+    @LocalData
+    public void canLoadUnstableReturnFromDisk() throws Exception {
+        FreeStyleProject p = (FreeStyleProject) rule.jenkins.getItemByFullName("test");
+        Shell shell = (Shell) p.getBuildersList().get(0);
+        assertEquals("unstable return", Integer.valueOf(1), shell.getUnstableReturn());
+    }
+
 }