[JENKINS-26718] Allow runs to be discarded even if their project can't be found by its fullname

(cherry picked from commit 327f7780)

core/src/main/java/hudson/diagnosis/OldDataMonitor.java

@@ -355,10 +355,12 @@ public class OldDataMonitor extends AdministrativeMonitor {
 
     private static SaveableReference referTo(Saveable s) {
         if (s instanceof Run) {
-            return new RunSaveableReference((Run) s);
-        } else {
-            return new SimpleSaveableReference(s);
+            Job parent = ((Run) s).getParent();
+            if (Jenkins.getInstance().getItemByFullName(parent.getFullName()) == parent) {
+                return new RunSaveableReference((Run) s);
+            }
         }
+        return new SimpleSaveableReference(s);
     }
 
     private static final class SimpleSaveableReference implements SaveableReference {

test/src/test/java/hudson/diagnosis/OldDataMonitorTest.java

@@ -41,11 +41,16 @@ import java.util.concurrent.ExecutorService;
 import java.util.concurrent.Executors;
 import java.util.concurrent.Future;
 
+import hudson.model.ItemGroup;
+import hudson.model.Job;
+import hudson.model.Run;
 import hudson.model.Saveable;
 import hudson.model.listeners.SaveableListener;
 import jenkins.model.Jenkins;
 import jenkins.model.lazy.BuildReference;
 import static org.junit.Assert.*;
+import static org.mockito.Mockito.*;
+
 import org.junit.Ignore;
 import org.junit.Rule;
 import org.junit.Test;
@@ -56,6 +61,8 @@ import org.jvnet.hudson.test.MemoryAssert;
 import org.jvnet.hudson.test.recipes.LocalData;
 import org.kohsuke.stapler.Stapler;
 
+import javax.annotation.Nonnull;
+
 public class OldDataMonitorTest {
 
     static {
@@ -149,6 +156,21 @@ public class OldDataMonitorTest {
 
     }
 
+    @Issue("JENKINS-26718")
+    @Test public void unlocatableRun() throws Exception {
+        OldDataMonitor odm = OldDataMonitor.get(r.jenkins);
+        FreeStyleProject p = mock(FreeStyleProject.class);
+        when(p.getParent()).thenReturn(Jenkins.getInstance());
+        when(p.getFullName()).thenReturn("notfound");
+        FreeStyleBuild build = new FreeStyleBuild(p);
+        odm.report(build, (String) null);
+
+        assertEquals(Collections.singleton(build), odm.getData().keySet());
+        odm.doDiscard(null, null);
+        assertEquals(Collections.emptySet(), odm.getData().keySet());
+
+    }
+
     public static final class BadAction extends InvisibleAction {
         private Object writeReplace() {
             throw new IllegalStateException("broken");