[FIXES JENKINS-47406] Milestone JOB_LOADED is now attained after cleaning up obsolete items (#3078)

* [FIXES JENKINS-47406] Milestone JOB_LOADED is now attained after cleaning up obsolete items

This allows @Initializer(after=InitMilestone.JOB_LOADED) implementations
to create items safely without risking them to be removed.

* [JENKINS-47406] Add test with an initializer creating a job

* Revert "[FIXES JENKINS-47406] Milestone JOB_LOADED is now attained after cleaning up obsolete items"

This reverts commit 79ce796b00.

* [JENKINS-47406] Reinstate the test with Jesse's solution

* Reverted this commit by mistake

Revert "Revert "[FIXES JENKINS-47406] Milestone JOB_LOADED is now attained after cleaning up obsolete items""

This reverts commit 36c499c58c.

* Add link to hpi sources

* Fix Mix-up after the previous merge

core/src/main/java/jenkins/model/Jenkins.java

@@ -3054,8 +3054,9 @@ public class Jenkins extends AbstractCIBase implements DirectlyModifiableTopLeve
             }
         });
 
+        List<Handle> loadJobs = new ArrayList<>();
         for (final File subdir : subdirs) {
-            g.requires(loadJenkins).attains(JOB_LOADED).notFatal().add("Loading item " + subdir.getName(), new Executable() {
+            loadJobs.add(g.requires(loadJenkins).attains(JOB_LOADED).notFatal().add("Loading item " + subdir.getName(), new Executable() {
                 public void run(Reactor session) throws Exception {
                     if(!Items.getConfigFile(subdir).exists()) {
                         //Does not have job config file, so it is not a jenkins job hence skip it
@@ -3065,10 +3066,10 @@ public class Jenkins extends AbstractCIBase implements DirectlyModifiableTopLeve
                     items.put(item.getName(), item);
                     loadedNames.add(item.getName());
                 }
-            });
+            }));
         }
 
-        g.requires(JOB_LOADED).attains(COMPLETED).add("Cleaning up obsolete items deleted from the disk", new Executable() {
+        g.requires(loadJobs.toArray(new Handle[loadJobs.size()])).attains(JOB_LOADED).add("Cleaning up obsolete items deleted from the disk", new Executable() {
             public void run(Reactor reactor) throws Exception {
                 // anything we didn't load from disk, throw them away.
                 // doing this after loading from disk allows newly loaded items

test/src/test/java/jenkins/model/JenkinsTest.java

@@ -23,6 +23,7 @@
  */
 package jenkins.model;
 
+import static hudson.init.InitMilestone.*;
 import static org.hamcrest.MatcherAssert.assertThat;
 import static org.hamcrest.Matchers.containsString;
 import static org.hamcrest.Matchers.greaterThan;
@@ -44,6 +45,7 @@ import com.gargoylesoftware.htmlunit.WebResponse;
 import com.gargoylesoftware.htmlunit.html.HtmlForm;
 import com.gargoylesoftware.htmlunit.html.HtmlPage;
 
+import hudson.init.Initializer;
 import hudson.maven.MavenModuleSet;
 import hudson.maven.MavenModuleSetBuild;
 import hudson.model.Computer;
@@ -72,6 +74,7 @@ import org.jvnet.hudson.test.ExtractResourceSCM;
 import org.jvnet.hudson.test.JenkinsRule;
 import org.jvnet.hudson.test.JenkinsRule.WebClient;
 import org.jvnet.hudson.test.TestExtension;
+import org.jvnet.hudson.test.recipes.WithPlugin;
 import org.kohsuke.stapler.HttpResponse;
 import org.mockito.ArgumentCaptor;
 import org.mockito.Mockito;
@@ -83,6 +86,7 @@ import java.net.URL;
 import java.util.Collections;
 import java.util.HashSet;
 import java.util.Set;
+import java.util.logging.Logger;
 import org.jvnet.hudson.test.MockAuthorizationStrategy;
 
 import javax.annotation.CheckForNull;
@@ -683,4 +687,11 @@ public class JenkinsTest {
         VersionNumber nullVersion = Jenkins.getStoredVersion();
         assertNull(nullVersion);
     }
+
+    @Issue("JENKINS-47406")
+    @Test
+    @WithPlugin("jenkins-47406.hpi") // Sources: https://github.com/Vlatombe/jenkins-47406
+    public void jobCreatedByInitializerIsRetained() {
+        assertNotNull("JENKINS-47406 should exist", j.jenkins.getItem("JENKINS-47406"));
+    }
 }