Get rid of isBuilding() check on previous build's culprits.

core/src/main/java/jenkins/scm/RunWithSCM.java

@@ -117,13 +117,11 @@ public interface RunWithSCM<JobT extends Job<JobT, RunT> & Queue.Task,
     default Set<User> calculateCulprits() {
         Set<User> r = new HashSet<>();
         RunT p = ((RunT)this).getPreviousCompletedBuild();
-        if (p != null && ((RunT)this).isBuilding()) {
+        if (p != null) {
             Result pr = p.getResult();
             if (pr != null && pr.isWorseThan(Result.SUCCESS)) {
                 // we are still building, so this is just the current latest information,
                 // but we seems to be failing so far, so inherit culprits from the previous build.
-                // isBuilding() check is to avoid recursion when loading data from old Hudson, which doesn't record
-                // this information
                 r.addAll(p.getCulprits());
             }
         }

test/src/test/java/hudson/model/AbstractBuildTest.java

@@ -34,8 +34,12 @@ import java.util.Arrays;
 import java.util.Collections;
 import java.util.Set;
 import java.util.TreeSet;
+import java.util.concurrent.TimeUnit;
+
 import static org.hamcrest.Matchers.*;
 import static org.junit.Assert.*;
+
+import hudson.tasks.LogRotatorTest;
 import org.junit.Rule;
 import org.junit.Test;
 import org.jvnet.hudson.test.CaptureEnvironmentBuilder;
@@ -132,6 +136,8 @@ public class AbstractBuildTest {
         FakeChangeLogSCM scm = new FakeChangeLogSCM();
         p.setScm(scm);
 
+        LogRotatorTest.StallBuilder sync = new LogRotatorTest.StallBuilder();
+
         // 1st build, successful, no culprits
         scm.addChange().withAuthor("alice");
         FreeStyleBuild b = j.buildAndAssertSuccess(p);
@@ -144,8 +150,15 @@ public class AbstractBuildTest {
         assertCulprits(b, "bob");
 
         // 3rd build. bob continues to be in culprit
+        p.getBuildersList().add(sync);
         scm.addChange().withAuthor("charlie");
-        b = j.assertBuildStatus(Result.FAILURE, p.scheduleBuild2(0).get());
+        b = p.scheduleBuild2(0).waitForStart();
+        sync.waitFor(b.getNumber(), 1, TimeUnit.SECONDS);
+
+        // Verify that we can get culprits while running.
+        assertCulprits(b, "bob", "charlie");
+        sync.release(b.getNumber());
+        j.assertBuildStatus(Result.FAILURE, j.waitForCompletion(b));
         assertCulprits(b, "bob", "charlie");
 
         // 4th build, unstable. culprit list should continue

test/src/test/java/hudson/tasks/LogRotatorTest.java

@@ -224,7 +224,7 @@ public class LogRotatorTest {
         }
     }
     
-    static class StallBuilder extends TestBuilder {
+    public static class StallBuilder extends TestBuilder {
         
         private int syncBuildNumber;