JENKINS-64946 : Branch indexing occurring for every multibranch job

execution

WHAT

1. If multibranch project trigger a build for a branch then it should
build for head which is in the Observer and not for all heads that
matches the multibranch.

src/main/java/org/jenkinsci/plugins/p4/scm/AbstractP4ScmSource.java

@@ -48,6 +48,7 @@
 import java.util.Arrays;
 import java.util.Collections;
 import java.util.List;
+import java.util.Set;
 import java.util.logging.Logger;
 
 import static org.jenkinsci.plugins.p4.review.ReviewProp.P4_CHANGE;
@@ -171,10 +172,7 @@ public String getScriptPathOrDefault() {
 	@Override
 	protected void retrieve(@CheckForNull SCMSourceCriteria criteria, @NonNull SCMHeadObserver observer, @CheckForNull SCMHeadEvent<?> event, @NonNull TaskListener listener) throws IOException, InterruptedException {
 		try (TempClientHelper p4 = new TempClientHelper(getOwner(), credential, listener, null)) {
-			List<P4SCMHead> heads = getHeads(listener);
-			List<P4SCMHead> tags = getTags(listener);
-			heads.addAll(tags);
-
+			List<P4SCMHead> heads = getP4SCMHeads(observer, listener);
 			for (P4SCMHead head : heads) {
 				logger.fine("SCM: retrieve Head: " + head);
 				retrieveHead(p4, head, criteria, observer, event);
@@ -184,6 +182,20 @@ protected void retrieve(@CheckForNull SCMSourceCriteria criteria, @NonNull SCMHe
 		}
 	}
 
+	private List<P4SCMHead> getP4SCMHeads(SCMHeadObserver observer, TaskListener listener) throws Exception {
+		List<P4SCMHead> heads = new ArrayList<>();
+		Set<SCMHead> includedHead = observer.getIncludes();
+		if (null != includedHead) {
+			for (SCMHead head : includedHead) {
+				heads.add((P4SCMHead) head);
+			}
+		} else {
+			heads.addAll(getHeads(listener));
+			heads.addAll(getTags(listener));
+		}
+		return heads;
+	}
+
 	private void retrieveHead(TempClientHelper p4, P4SCMHead head, SCMSourceCriteria criteria, SCMHeadObserver observer, SCMHeadEvent<?> event) throws Exception {
 		P4Path p4Path = head.getPath();
 		Workspace workspace = getWorkspace(p4Path);

src/test/java/org/jenkinsci/plugins/p4/scm/PerforceSCMSourceTest.java

@@ -46,17 +46,23 @@
 import org.jvnet.hudson.test.Issue;
 import org.jvnet.hudson.test.JenkinsRule;
 
+import java.io.BufferedReader;
+import java.io.File;
+import java.io.FileReader;
+import java.nio.file.Files;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.HashMap;
 import java.util.List;
+import java.util.Objects;
 import java.util.logging.Logger;
 
 import static org.hamcrest.Matchers.containsInAnyOrder;
 import static org.hamcrest.Matchers.is;
 import static org.hamcrest.Matchers.not;
 import static org.hamcrest.core.IsNull.notNullValue;
 import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
 import static org.junit.Assert.assertNotNull;
 import static org.junit.Assert.assertNull;
 import static org.junit.Assert.assertThat;
@@ -170,6 +176,36 @@ public void testExcludesWithClassic() throws Exception {
 		assertEquals(1, multi.getItems().size());
 	}
 
+	@Test
+	public void testAJobShouldNotCreateClientForOtherJobsInAMultibranchProject() throws Exception {
+
+		String project = "multi";
+		String base = "//depot/" + project;
+		String[] branches = new String[]{"br1", "br2"};
+
+		sampleProject(base, branches, "Jenkinsfile");
+
+		String format = "jenkins-${NODE_NAME}-${JOB_NAME}";
+		String includes = base + "/...";
+		BranchesScmSource source = new BranchesScmSource(CREDENTIAL, includes, null, format);
+
+		WorkflowMultiBranchProject multi = jenkins.jenkins.createProject(WorkflowMultiBranchProject.class, project);
+		multi.getSourcesList().add(new BranchSource(source));
+		multi.scheduleBuild2(0);
+		jenkins.waitUntilNoActivity();
+
+		WorkflowJob job = multi.getItem("br1");
+		File logFile = Objects.requireNonNull(job).getLastBuild().getLogFile();
+		BufferedReader br = new BufferedReader(new FileReader(logFile));
+		StringBuilder builder = new StringBuilder();
+		String line;
+		while((line = br.readLine()) !=null){
+			builder.append(line);
+		}
+		assertTrue("A Job should include its branch in console logs",builder.toString().contains("//depot/multi/br1"));
+		assertFalse("A job should not include other job branch in console logs",builder.toString().contains("//depot/multi/br2"));
+	}
+
 	@Test
 	public void testExcludesWithSwarm() throws Exception {