[JENKINS-48061] Introduce GitRefSCMHead

src/main/java/jenkins/plugins/git/AbstractGitSCMSource.java

@@ -809,11 +809,15 @@ public SCMRevision run(GitClient client, String remoteName) throws IOException,
                     context,
                     listener, false);
         }
+        if (revision.matches("[a-f0-9]{40}")) {
+            return new GitRefSCMRevision(new GitRefSCMHead(revision, revision), revision);
+        }
         // Pokémon!... Got to catch them all
         listener.getLogger().printf("Could not find %s in remote references. "
                         + "Pulling heads to local for deep search...%n", revision);
         context.wantTags(true);
         context.wantBranches(true);
+
         return doRetrieve(new Retriever<SCMRevision>() {
                               @Override
                               public SCMRevision run(GitClient client, String remoteName) throws IOException, InterruptedException {

src/main/java/jenkins/plugins/git/GitRefSCMHead.java

@@ -0,0 +1,23 @@
+package jenkins.plugins.git;
+
+import edu.umd.cs.findbugs.annotations.NonNull;
+import jenkins.scm.api.SCMHead;
+import jenkins.scm.api.mixin.SCMHeadMixin;
+
+public class GitRefSCMHead extends SCMHead implements SCMHeadMixin {
+    private final String ref;
+
+    /**
+     * Constructor.
+     *
+     * @param name the name.
+     */
+    public GitRefSCMHead(@NonNull String name, String ref) {
+        super(name);
+        this.ref = ref;
+    }
+
+    public String getRef() {
+        return ref;
+    }
+}

src/main/java/jenkins/plugins/git/GitRefSCMRevision.java

@@ -0,0 +1,8 @@
+package jenkins.plugins.git;
+
+public class GitRefSCMRevision extends AbstractGitSCMSource.SCMRevisionImpl {
+
+    public GitRefSCMRevision(GitRefSCMHead head, String hash) {
+        super(head, hash);
+    }
+}

src/main/java/jenkins/plugins/git/GitSCMBuilder.java

@@ -514,6 +514,9 @@ public GitSCM build() {
             extensions.add(new BuildChooserSetting(new AbstractGitSCMSource.SpecificRevisionBuildChooser(
                     (AbstractGitSCMSource.SCMRevisionImpl) revision)));
         }
+        if (head() instanceof GitRefSCMHead) {
+            withoutRefSpecs().withRefSpec(((GitRefSCMHead) head()).getRef());
+        }
         return new GitSCM(
                 asRemoteConfigs(),
                 Collections.singletonList(new BranchSpec(head().getName())),

src/test/java/jenkins/plugins/git/AbstractGitSCMSourceTest.java

@@ -456,7 +456,7 @@ public void retrieveRevision_nonHead() throws Exception {
 
     @Issue("JENKINS-48061")
     @Test
-    @Ignore("Cannot fix until JENKINS-48385 merged") // TODO unignore once JENKINS-48385
+    @Ignore("At least file:// protocol doesn't allow fetching unannounced commits")
     public void retrieveRevision_nonAdvertised() throws Exception {
         sampleRepo.init();
         sampleRepo.write("file", "v1");
@@ -483,7 +483,6 @@ public void retrieveRevision_nonAdvertised() throws Exception {
 
     @Issue("JENKINS-48061")
     @Test
-    @Ignore("Cannot fix until JENKINS-48385 merged") // TODO unignore once JENKINS-48385
     public void retrieveRevision_customRef() throws Exception {
         sampleRepo.init();
         sampleRepo.write("file", "v1");