Merge pull request #497 from vgaidarji/vgaidarji/improve-logs-output

[JENKINS-38241] Print commit message to log on checkout

CONTRIBUTING.md

@@ -24,6 +24,9 @@ your best to improve code coverage with tests when you submit.
 
 Before submitting your change, please review the findbugs output to
 assure that you haven't introduced new findbugs warnings.
+- `mvn findbugs:check` to analyze project using [Findbugs](http://findbugs.sourceforge.net/)
+- `mvn findbugs:gui` to check Findbugs report using GUI
+
 
 Code formatting in the git plugin varies between files.  Try to
 maintain reasonable consistency with the existing files where

src/main/java/hudson/plugins/git/GitSCM.java

@@ -46,6 +46,7 @@
 
 import org.eclipse.jgit.lib.Config;
 import org.eclipse.jgit.lib.ObjectId;
+import org.eclipse.jgit.revwalk.RevCommit;
 import org.eclipse.jgit.transport.RefSpec;
 import org.eclipse.jgit.transport.RemoteConfig;
 import org.eclipse.jgit.transport.URIish;
@@ -1148,6 +1149,9 @@ public void checkout(Run<?, ?> build, Launcher launcher, FilePath workspace, Tas
         }
 
         listener.getLogger().println("Checking out " + revToBuild.revision);
+
+        printCommitMessageToLog(listener, git, revToBuild);
+
         CheckoutCommand checkoutCommand = git.checkout().branch(localBranchName).ref(revToBuild.revision.getSha1String()).deleteBranchIfExist(true);
         for (GitSCMExtension ext : this.getExtensions()) {
             ext.decorateCheckoutCommand(this, build, git, listener, checkoutCommand);
@@ -1179,6 +1183,16 @@ public void checkout(Run<?, ?> build, Launcher launcher, FilePath workspace, Tas
         }
     }
 
+    private void printCommitMessageToLog(TaskListener listener, GitClient git, final Build revToBuild)
+            throws IOException {
+        try {
+            RevCommit commit = git.withRepository(new RevCommitRepositoryCallback(revToBuild));
+            listener.getLogger().println("Commit message: \"" + commit.getShortMessage() + "\"");
+        } catch (InterruptedException e) {
+            e.printStackTrace(listener.error("Unable to retrieve commit message"));
+        }
+    }
+
     /**
      * Build up change log from all the branches that we've merged into {@code revToBuild}.
      *

src/main/java/hudson/plugins/git/browser/GitRepositoryBrowser.java

@@ -35,7 +35,7 @@ public final URL getUrl() throws IOException {
         if (req != null) {
             Job job = req.findAncestorObject(Job.class);
             if (job != null) {
-                EnvVars env = null;
+                EnvVars env;
                 try {
                     env = job.getEnvironment(null, TaskListener.NULL);
                 } catch (InterruptedException e) {

src/main/java/hudson/plugins/git/util/RevCommitRepositoryCallback.java

@@ -0,0 +1,28 @@
+package hudson.plugins.git.util;
+
+import hudson.remoting.VirtualChannel;
+import java.io.IOException;
+import org.eclipse.jgit.lib.Repository;
+import org.eclipse.jgit.revwalk.RevCommit;
+import org.eclipse.jgit.revwalk.RevWalk;
+import org.jenkinsci.plugins.gitclient.RepositoryCallback;
+
+/**
+ * Retrieves {@link RevCommit} from given {@link Build} revision.
+ */
+public final class RevCommitRepositoryCallback implements RepositoryCallback<RevCommit> {
+    private static final long serialVersionUID = 1L;
+    private final Build revToBuild;
+
+    public RevCommitRepositoryCallback(Build revToBuild) {
+        this.revToBuild = revToBuild;
+    }
+
+    @Override
+    public RevCommit invoke(Repository repository, VirtualChannel virtualChannel)
+            throws IOException, InterruptedException {
+        try (RevWalk walk = new RevWalk(repository)) {
+            return walk.parseCommit(revToBuild.revision.getSha1());
+        }
+    }
+}

src/test/java/hudson/plugins/git/GitSCMTest.java

@@ -78,8 +78,10 @@
 import org.junit.Before;
 import org.junit.BeforeClass;
 
+import org.mockito.ArgumentCaptor;
 import org.mockito.Mockito;
 import static org.mockito.Matchers.*;
+import static org.mockito.Mockito.atLeastOnce;
 import static org.mockito.Mockito.times;
 import static org.mockito.Mockito.verify;
 
@@ -2286,7 +2288,28 @@ public void testBuildEnvVarsLocalBranchNotSet() throws Exception {
        verify(buildData, times(1)).hasBeenReferenced(anyString());
        verify(build, times(1)).getActions(BuildData.class);
     }
-
+
+    @Issue("JENKINS-38241")
+    @Test
+    public void testCommitMessageIsPrintedToLogs() throws Exception {
+        sampleRepo.init();
+        sampleRepo.write("file", "v1");
+        sampleRepo.git("commit", "--all", "--message=test commit");
+        FreeStyleProject p = setupSimpleProject("master");
+        Run<?,?> run = rule.buildAndAssertSuccess(p);
+        TaskListener mockListener = Mockito.mock(TaskListener.class);
+        Mockito.when(mockListener.getLogger()).thenReturn(Mockito.spy(StreamTaskListener.fromStdout().getLogger()));
+
+        p.getScm().checkout(run, new Launcher.LocalLauncher(listener),
+                new FilePath(run.getRootDir()).child("tmp-" + "master"),
+                mockListener, null, SCMRevisionState.NONE);
+
+        ArgumentCaptor<String> logCaptor = ArgumentCaptor.forClass(String.class);
+        verify(mockListener.getLogger(), atLeastOnce()).println(logCaptor.capture());
+        List<String> values = logCaptor.getAllValues();
+        assertThat(values, hasItem("Commit message: \"test commit\""));
+    }
+
     /**
      * Method performs HTTP get on "notifyCommit" URL, passing it commit by SHA1
      * and tests for build data consistency.