From 9d5242885e4cad5accfd81dbb0ea0a2fd115644e Mon Sep 17 00:00:00 2001
From: Ulli Hafner <ullrich.hafner@gmail.com>
Date: Sun, 27 Jun 2021 23:42:00 +0200
Subject: [PATCH 1/7] Add delta forensics for PR and branch builds.

---
 .../forensics/miner/ForensicsBuildAction.java | 64 ++++++++++++++++---
 .../forensics/miner/RepositoryMiner.java      | 26 +++++++-
 .../forensics/miner/RepositoryMinerStep.java  | 49 +++++++++++---
 .../miner/ForensicsBuildAction/summary.jelly  | 26 +++++---
 4 files changed, 136 insertions(+), 29 deletions(-)

diff --git a/src/main/java/io/jenkins/plugins/forensics/miner/ForensicsBuildAction.java b/src/main/java/io/jenkins/plugins/forensics/miner/ForensicsBuildAction.java
index 34011f98..27263e2d 100644
--- a/src/main/java/io/jenkins/plugins/forensics/miner/ForensicsBuildAction.java
+++ b/src/main/java/io/jenkins/plugins/forensics/miner/ForensicsBuildAction.java
@@ -2,12 +2,15 @@
 
 import org.apache.commons.lang3.StringUtils;
 
+import edu.hm.hafner.util.FilteredLog;
+import edu.hm.hafner.util.NoSuchElementException;
 import edu.hm.hafner.util.VisibleForTesting;
 import edu.umd.cs.findbugs.annotations.SuppressFBWarnings;
 
 import org.kohsuke.stapler.StaplerProxy;
 import hudson.model.Run;
 
+import io.jenkins.plugins.forensics.reference.ReferenceFinder;
 import io.jenkins.plugins.util.BuildAction;
 
 /**
@@ -21,17 +24,22 @@ public class ForensicsBuildAction extends BuildAction<RepositoryStatistics> impl
     private static final long serialVersionUID = -263122257268060032L;
     private static final String DEFAULT_FILE_NAME = "repository-statistics.xml";
 
-    private final int numberOfFiles;
     private final int miningDurationSeconds;
     private final String urlName;
 
     private String scmKey; // since 0.9.0
     private String fileName; // since 0.9.0
 
+    private final int numberOfFiles;
     private final int totalLinesOfCode; // since 1.1.0
     private final int totalChurn; // since 1.1.0
     private CommitStatistics commitStatistics;  // since 1.1.0
 
+    private final int deltaNumberOfFiles; // since 1.2.0
+    private final int deltaTotalLinesOfCode; // since 1.2.0
+    private final int deltaTotalChurn; // since 1.2.0
+    private CommitStatistics deltaCommitStatistics; // since 1.2.0
+
     /**
      * Creates a new instance of {@link ForensicsBuildAction}.
      *
@@ -48,7 +56,7 @@ public class ForensicsBuildAction extends BuildAction<RepositoryStatistics> impl
      */
     public ForensicsBuildAction(final Run<?, ?> owner, final RepositoryStatistics repositoryStatistics,
             final int miningDurationSeconds, final String scmKey, final int number) {
-        this(owner, repositoryStatistics, true, miningDurationSeconds, scmKey, number);
+        this(owner, repositoryStatistics, new RepositoryStatistics(), miningDurationSeconds, scmKey, number);
     }
 
     /**
@@ -58,8 +66,8 @@ public ForensicsBuildAction(final Run<?, ?> owner, final RepositoryStatistics re
      *         the associated build that created the statistics
      * @param repositoryStatistics
      *         the statistics to persist with this action
-     * @param canSerialize
-     *         determines whether the result should be persisted in the build folder
+     * @param deltaStatistics
+     *         the statistics compared to the reference build (if available)
      * @param miningDurationSeconds
      *         the duration of the mining operation in [s]
      * @param scmKey
@@ -67,22 +75,34 @@ public ForensicsBuildAction(final Run<?, ?> owner, final RepositoryStatistics re
      * @param number
      *         unique number of the results (used as part of the serialization file name)
      */
+    public ForensicsBuildAction(final Run<?, ?> owner,
+            final RepositoryStatistics repositoryStatistics, final RepositoryStatistics deltaStatistics,
+            final int miningDurationSeconds, final String scmKey, final int number) {
+        this(owner, repositoryStatistics, deltaStatistics, true, miningDurationSeconds, scmKey, number);
+    }
+
     @VisibleForTesting
-    ForensicsBuildAction(final Run<?, ?> owner, final RepositoryStatistics repositoryStatistics,
+    ForensicsBuildAction(final Run<?, ?> owner,
+            final RepositoryStatistics repositoryStatistics, final RepositoryStatistics deltaStatistics,
             final boolean canSerialize, final int miningDurationSeconds, final String scmKey, final int number) {
         super(owner, repositoryStatistics, false);
 
-        numberOfFiles = repositoryStatistics.size();
         this.miningDurationSeconds = miningDurationSeconds;
         this.scmKey = scmKey;
 
         fileName = createFileName(number);
         urlName = createUrlName(number);
 
+        numberOfFiles = repositoryStatistics.size();
         totalLinesOfCode = repositoryStatistics.getTotalLinesOfCode();
         totalChurn = repositoryStatistics.getTotalChurn();
         commitStatistics = repositoryStatistics.getLatestStatistics();
 
+        deltaNumberOfFiles = deltaStatistics.size();
+        deltaTotalLinesOfCode = deltaStatistics.getTotalLinesOfCode();
+        deltaTotalChurn = deltaStatistics.getTotalChurn();
+        deltaCommitStatistics = deltaStatistics.getLatestStatistics();
+
         if (canSerialize) {
             createXmlStream().write(owner.getRootDir().toPath().resolve(fileName), repositoryStatistics);
         }
@@ -100,6 +120,9 @@ protected Object readResolve() {
         if (commitStatistics == null) {
             commitStatistics = new CommitStatistics();
         }
+        if (deltaCommitStatistics == null) {
+            deltaCommitStatistics = new CommitStatistics();
+        }
 
         return super.readResolve();
     }
@@ -158,14 +181,14 @@ public String getUrlName() {
         return urlName;
     }
 
-    public int getNumberOfFiles() {
-        return numberOfFiles;
-    }
-
     public int getMiningDurationSeconds() {
         return miningDurationSeconds;
     }
 
+    public int getNumberOfFiles() {
+        return numberOfFiles;
+    }
+
     public int getTotalLinesOfCode() {
         return totalLinesOfCode;
     }
@@ -178,6 +201,27 @@ public CommitStatistics getCommitStatistics() {
         return commitStatistics;
     }
 
+    public Run<?, ?> getReferenceBuild() {
+        return new ReferenceFinder().findReference(getOwner(), new FilteredLog(""))
+                .orElseThrow(() -> new NoSuchElementException("No reference build available"));
+    }
+
+    public int getDeltaNumberOfFiles() {
+        return deltaNumberOfFiles;
+    }
+
+    public int getDeltaTotalLinesOfCode() {
+        return deltaTotalLinesOfCode;
+    }
+
+    public int getDeltaTotalChurn() {
+        return deltaTotalChurn;
+    }
+
+    public CommitStatistics getDeltaCommitStatistics() {
+        return deltaCommitStatistics;
+    }
+
     public String getScmKey() {
         return scmKey;
     }
diff --git a/src/main/java/io/jenkins/plugins/forensics/miner/RepositoryMiner.java b/src/main/java/io/jenkins/plugins/forensics/miner/RepositoryMiner.java
index 2cba2ead..e016ebb9 100644
--- a/src/main/java/io/jenkins/plugins/forensics/miner/RepositoryMiner.java
+++ b/src/main/java/io/jenkins/plugins/forensics/miner/RepositoryMiner.java
@@ -4,6 +4,8 @@
 
 import edu.hm.hafner.util.FilteredLog;
 
+import hudson.model.Run;
+
 /**
  * Obtains commit statistics for a source code repository. Computation of the commit statistics should be done
  * incrementally, if supported by the underlying SCM  (i.e., only commits new in the current build should be
@@ -15,7 +17,10 @@ public abstract class RepositoryMiner implements Serializable {
     private static final long serialVersionUID = -8878714986510536182L;
 
     /**
-     * Obtains commit statistics for a source code repository.
+     * Obtains commit statistics for a source code repository. If the {@code previousStatistics} are filled with results
+     * of a previous build, then an incremental mining will be started that only inspects the additional commits from
+     * the current build. Otherwise, the whole repository will be mined (which might take some time for large
+     * repositories).
      *
      * @param previousStatistics
      *         the repository statistics of the previous build - if there is no such build then an empty instance will
@@ -30,6 +35,25 @@ public abstract class RepositoryMiner implements Serializable {
     public abstract RepositoryStatistics mine(RepositoryStatistics previousStatistics, FilteredLog logger)
             throws InterruptedException;
 
+    /**
+     * Obtains delta commit statistics for a source code repository. Starts an incremental mining from the latest commit
+     * from the current build up to the common ancestor commit with the provided {@code referenceBuild}.
+     *
+     * @param referenceBuild
+     *         the reference build to use
+     * @param logger
+     *         the logger to use
+     *
+     * @return the statistics containing the commit statistics for the current build up to the common ancestor with the
+     *         reference build
+     * @throws InterruptedException
+     *         if the user canceled the processing
+     * @since 1.2.0
+     */
+    public RepositoryStatistics mine(final Run<?, ?> referenceBuild, final FilteredLog logger) throws InterruptedException {
+        return new RepositoryStatistics();
+    }
+
     /**
      * A repository miner that does nothing.
      */
diff --git a/src/main/java/io/jenkins/plugins/forensics/miner/RepositoryMinerStep.java b/src/main/java/io/jenkins/plugins/forensics/miner/RepositoryMinerStep.java
index 0cca6a6e..ca4865da 100644
--- a/src/main/java/io/jenkins/plugins/forensics/miner/RepositoryMinerStep.java
+++ b/src/main/java/io/jenkins/plugins/forensics/miner/RepositoryMinerStep.java
@@ -1,6 +1,7 @@
 package io.jenkins.plugins.forensics.miner;
 
 import java.util.List;
+import java.util.Optional;
 
 import org.apache.commons.lang3.StringUtils;
 
@@ -25,6 +26,7 @@
 import hudson.tasks.Recorder;
 import jenkins.tasks.SimpleBuildStep;
 
+import io.jenkins.plugins.forensics.reference.ReferenceFinder;
 import io.jenkins.plugins.forensics.util.ScmResolver;
 import io.jenkins.plugins.util.BuildAction;
 import io.jenkins.plugins.util.LogHandler;
@@ -106,31 +108,60 @@ private void mineRepositories(final Run<?, ?> run, final FilePath workspace, fin
             RepositoryMiner miner = MinerFactory.findMiner(repository, run, workspace, listener, logger);
             logHandler.log(logger);
 
-            RepositoryStatistics repositoryStatistics = previousBuildStatistics(scm, run);
+            RepositoryStatistics repositoryStatistics = previousBuildStatistics(run);
             RepositoryStatistics addedRepositoryStatistics = miner.mine(repositoryStatistics, logger);
 
+            RepositoryStatistics deltaStatistics = createDeltaStatistics(miner, run, logger);
+
             logHandler.log(logger);
             int miningDurationSeconds = (int) (1 + (System.nanoTime() - startOfMining) / 1_000_000_000L);
-            run.addAction(new ForensicsBuildAction(run, addedRepositoryStatistics, miningDurationSeconds,
-                    repository.getKey(), number++));
+            run.addAction(new ForensicsBuildAction(run, addedRepositoryStatistics, deltaStatistics,
+                    miningDurationSeconds, repository.getKey(), number++));
         }
     }
 
-    private RepositoryStatistics previousBuildStatistics(final String repository, final Run<?, ?> run) {
+    /**
+     * Returns the delta statistics of the current build compared to the best common ancestor commit with the reference
+     * build. If no reference build has been found, then an empty mining result is returned.
+     *
+     * @param miner
+     *         the miner
+     * @param run
+     *         the current build
+     * @param logger
+     *         the logger
+     *
+     * @return the delta statistics if a reference build with previous results has been found
+     * @throws InterruptedException
+     *         if the user stops the processing
+     */
+    private RepositoryStatistics createDeltaStatistics(final RepositoryMiner miner,
+            final Run<?, ?> run, final FilteredLog logger) throws InterruptedException {
+        Optional<Run<?, ?>> referenceBuild = new ReferenceFinder().findReference(run, logger);
+        if (referenceBuild.isPresent()) { // can't use streams due to checked exception
+            return miner.mine(referenceBuild.get(), logger);
+        }
+        return new RepositoryStatistics();
+    }
+
+    private RepositoryStatistics previousBuildStatistics(final Run<?, ?> run) {
         for (Run<?, ?> build = run.getPreviousBuild(); build != null; build = build.getPreviousBuild()) {
             List<ForensicsBuildAction> actions = build.getActions(ForensicsBuildAction.class);
             if (!actions.isEmpty()) {
-                return actions.stream()
-                        .filter(a -> a.getScmKey().contains(repository))
-                        .findAny()
-                        .map(BuildAction::getResult)
-                        .orElse(new RepositoryStatistics());
+                return extractResult(actions).orElse(new RepositoryStatistics());
             }
         }
 
         return new RepositoryStatistics();
     }
 
+    private Optional<RepositoryStatistics> extractResult(final List<ForensicsBuildAction> actions) {
+        return actions.stream()
+                .filter(a -> a.getScmKey().contains(scm))
+                .findAny()
+                .map(BuildAction::getResult);
+    }
+
     @Override
     public Descriptor getDescriptor() {
         return (Descriptor) super.getDescriptor();
diff --git a/src/main/resources/io/jenkins/plugins/forensics/miner/ForensicsBuildAction/summary.jelly b/src/main/resources/io/jenkins/plugins/forensics/miner/ForensicsBuildAction/summary.jelly
index 04ef129b..5eeb69fe 100644
--- a/src/main/resources/io/jenkins/plugins/forensics/miner/ForensicsBuildAction/summary.jelly
+++ b/src/main/resources/io/jenkins/plugins/forensics/miner/ForensicsBuildAction/summary.jelly
@@ -3,21 +3,29 @@
 
   <t:summary icon="/plugin/forensics-api/icons/forensics-48x48.png">
     ${%title}: ${it.scmKey}
-    <j:set var="s" value="${it.result.latestStatistics}" />
+    <j:set var="s" value="${it.commitStatistics}" />
+    <j:set var="d" value="${it.deltaCommitStatistics}" />
     <ul>
       <li>
         <a href="${it.urlName}">${%summary(size(it.result))}</a>
-        (total lines of code: ${it.result.totalLinesOfCode}, total churn: ${it.result.totalChurn})
+        (total lines of code: ${it.totalLinesOfCode}, total churn: ${it.totalChurn})
       </li>
       <li>
-        New commits: ${s.commitCount} (from ${s.authorCount} authors in ${s.filesCount} files)
-      </li>
-      <li>
-        New added lines: ${s.addedLines}
-      </li>
-      <li>
-        New deleted lines: ${s.deletedLines}
+        New commits since previous build: ${s.commitCount}
+          (from ${s.authorCount} authors
+            in ${s.filesCount} files
+            with ${s.addedLines} added
+            and ${s.deletedLines} deleted lines)
       </li>
+      <j:if test="${it.deltaNumberOfFiles > 0}">
+        <li>
+          New commits since reference build <a href="${rootURL}/${it.referenceBuild.url}">${it.referenceBuild.displayName}</a>: ${d.commitCount}
+          (from ${d.authorCount} authors
+          in ${d.filesCount} files
+          with ${d.addedLines} added
+          and ${d.deletedLines} deleted lines)
+        </li>
+      </j:if>
       <li>
         Miner runtime: ${it.miningDurationSeconds} seconds
       </li>

From 58150b80d4d0e36ff736ff311d87be5416e28dc9 Mon Sep 17 00:00:00 2001
From: Ulli Hafner <ullrich.hafner@gmail.com>
Date: Mon, 28 Jun 2021 09:45:02 +0200
Subject: [PATCH 2/7] Allow dependency from miner to reference.

---
 .../io/jenkins/plugins/forensics/miner/ForensicsBuildAction.java | 1 +
 src/test/resources/design.puml                                   | 1 +
 2 files changed, 2 insertions(+)

diff --git a/src/main/java/io/jenkins/plugins/forensics/miner/ForensicsBuildAction.java b/src/main/java/io/jenkins/plugins/forensics/miner/ForensicsBuildAction.java
index 27263e2d..89779a5d 100644
--- a/src/main/java/io/jenkins/plugins/forensics/miner/ForensicsBuildAction.java
+++ b/src/main/java/io/jenkins/plugins/forensics/miner/ForensicsBuildAction.java
@@ -20,6 +20,7 @@
  *
  * @author Ullrich Hafner
  */
+@SuppressWarnings("PMD.DataClass")
 public class ForensicsBuildAction extends BuildAction<RepositoryStatistics> implements StaplerProxy {
     private static final long serialVersionUID = -263122257268060032L;
     private static final String DEFAULT_FILE_NAME = "repository-statistics.xml";
diff --git a/src/test/resources/design.puml b/src/test/resources/design.puml
index dd5ced63..e909e65a 100644
--- a/src/test/resources/design.puml
+++ b/src/test/resources/design.puml
@@ -14,6 +14,7 @@ skinparam component {
 
 [Blamer] --> [Utilities]
 [Miner] --> [Utilities]
+[Miner] -> [Reference Recorder]
 [Reference Recorder] --> [Utilities]
 
 @enduml

From 695ab1ece273939f4eaae6bb721018574b77333c Mon Sep 17 00:00:00 2001
From: Ulli Hafner <ullrich.hafner@gmail.com>
Date: Thu, 1 Jul 2021 00:26:13 +0200
Subject: [PATCH 3/7] Create a new action that stores the commit diffs.

---
 .../miner/CommitStatisticsBuildAction.java    |  86 ++++++++++++++++++
 .../forensics/miner/ForensicsBuildAction.java |  64 ++-----------
 .../forensics/miner/RepositoryMiner.java      |  26 +-----
 .../forensics/miner/RepositoryMinerStep.java  |  52 +++--------
 .../CommitStatisticsBuildAction/summary.jelly |  20 ++++
 .../summary.properties                        |   1 +
 src/main/webapp/icons/LICENSE.txt             |   2 +-
 src/main/webapp/icons/diff-stat-24x24.png     | Bin 0 -> 576 bytes
 src/main/webapp/icons/diff-stat-48x48.png     | Bin 0 -> 796 bytes
 9 files changed, 131 insertions(+), 120 deletions(-)
 create mode 100644 src/main/java/io/jenkins/plugins/forensics/miner/CommitStatisticsBuildAction.java
 create mode 100644 src/main/resources/io/jenkins/plugins/forensics/miner/CommitStatisticsBuildAction/summary.jelly
 create mode 100644 src/main/resources/io/jenkins/plugins/forensics/miner/CommitStatisticsBuildAction/summary.properties
 create mode 100644 src/main/webapp/icons/diff-stat-24x24.png
 create mode 100644 src/main/webapp/icons/diff-stat-48x48.png

diff --git a/src/main/java/io/jenkins/plugins/forensics/miner/CommitStatisticsBuildAction.java b/src/main/java/io/jenkins/plugins/forensics/miner/CommitStatisticsBuildAction.java
new file mode 100644
index 00000000..66eca458
--- /dev/null
+++ b/src/main/java/io/jenkins/plugins/forensics/miner/CommitStatisticsBuildAction.java
@@ -0,0 +1,86 @@
+package io.jenkins.plugins.forensics.miner;
+
+import java.io.Serializable;
+import java.util.Collection;
+import java.util.Collections;
+
+import edu.umd.cs.findbugs.annotations.CheckForNull;
+
+import hudson.model.Action;
+import hudson.model.InvisibleAction;
+import hudson.model.Run;
+import jenkins.model.RunAction2;
+import jenkins.tasks.SimpleBuildStep.LastBuildAction;
+
+import io.jenkins.plugins.forensics.reference.ReferenceBuild;
+
+/**
+ * Controls the life cycle of the commit statistics in a job. This action persists the results of a build and displays a
+ * summary on the build page. The actual visualization of the results is defined in the matching {@code summary.jelly}
+ * file.
+ *
+ * @author Ullrich Hafner
+ */
+@SuppressWarnings("PMD.DataClass")
+public class CommitStatisticsBuildAction extends InvisibleAction implements LastBuildAction, RunAction2, Serializable {
+    private static final long serialVersionUID = -263122257268060032L;
+
+    private Run<?, ?> owner;
+
+    private final String scmKey;
+    private final CommitStatistics commitStatistics;
+
+    /**
+     * Creates a new instance of {@link CommitStatisticsBuildAction}.
+     *
+     * @param owner
+     *         the associated build that created the statistics
+     * @param scmKey
+     *         key of the repository
+     * @param commitStatistics
+     *         the statistics to persist with this action
+     */
+    public CommitStatisticsBuildAction(final Run<?, ?> owner,
+            final String scmKey, final CommitStatistics commitStatistics) {
+        this.owner = owner;
+        this.scmKey = scmKey;
+        this.commitStatistics = commitStatistics;
+    }
+
+    public Run<?, ?> getOwner() {
+        return owner;
+    }
+
+    public String getScmKey() {
+        return scmKey;
+    }
+
+    public CommitStatistics getCommitStatistics() {
+        return commitStatistics;
+    }
+
+    @CheckForNull
+    public ReferenceBuild getReferenceBuild() {
+        return getOwner().getAction(ReferenceBuild.class);
+    }
+
+    @Override
+    public String toString() {
+        return String.format("%s [%s]", scmKey, commitStatistics);
+    }
+
+    @Override
+    public void onAttached(final Run<?, ?> run) {
+        owner = run;
+    }
+
+    @Override
+    public void onLoad(final Run<?, ?> run) {
+        owner = run;
+    }
+
+    @Override
+    public Collection<? extends Action> getProjectActions() {
+        return Collections.emptyList();
+    }
+}
diff --git a/src/main/java/io/jenkins/plugins/forensics/miner/ForensicsBuildAction.java b/src/main/java/io/jenkins/plugins/forensics/miner/ForensicsBuildAction.java
index 89779a5d..24540ca8 100644
--- a/src/main/java/io/jenkins/plugins/forensics/miner/ForensicsBuildAction.java
+++ b/src/main/java/io/jenkins/plugins/forensics/miner/ForensicsBuildAction.java
@@ -2,19 +2,16 @@
 
 import org.apache.commons.lang3.StringUtils;
 
-import edu.hm.hafner.util.FilteredLog;
-import edu.hm.hafner.util.NoSuchElementException;
 import edu.hm.hafner.util.VisibleForTesting;
 import edu.umd.cs.findbugs.annotations.SuppressFBWarnings;
 
 import org.kohsuke.stapler.StaplerProxy;
 import hudson.model.Run;
 
-import io.jenkins.plugins.forensics.reference.ReferenceFinder;
 import io.jenkins.plugins.util.BuildAction;
 
 /**
- * Controls the live cycle of the forensics results in a job. This action persists the results of a build and displays a
+ * Controls the life cycle of the forensics results in a job. This action persists the results of a build and displays a
  * summary on the build page. The actual visualization of the results is defined in the matching {@code summary.jelly}
  * file. This action also provides access to the forensics details: these are rendered using a new view instance.
  *
@@ -36,11 +33,6 @@ public class ForensicsBuildAction extends BuildAction<RepositoryStatistics> impl
     private final int totalChurn; // since 1.1.0
     private CommitStatistics commitStatistics;  // since 1.1.0
 
-    private final int deltaNumberOfFiles; // since 1.2.0
-    private final int deltaTotalLinesOfCode; // since 1.2.0
-    private final int deltaTotalChurn; // since 1.2.0
-    private CommitStatistics deltaCommitStatistics; // since 1.2.0
-
     /**
      * Creates a new instance of {@link ForensicsBuildAction}.
      *
@@ -57,7 +49,7 @@ public class ForensicsBuildAction extends BuildAction<RepositoryStatistics> impl
      */
     public ForensicsBuildAction(final Run<?, ?> owner, final RepositoryStatistics repositoryStatistics,
             final int miningDurationSeconds, final String scmKey, final int number) {
-        this(owner, repositoryStatistics, new RepositoryStatistics(), miningDurationSeconds, scmKey, number);
+        this(owner, repositoryStatistics, true, miningDurationSeconds, scmKey, number);
     }
 
     /**
@@ -67,8 +59,8 @@ public ForensicsBuildAction(final Run<?, ?> owner, final RepositoryStatistics re
      *         the associated build that created the statistics
      * @param repositoryStatistics
      *         the statistics to persist with this action
-     * @param deltaStatistics
-     *         the statistics compared to the reference build (if available)
+     * @param canSerialize
+     *         determines whether the result should be persisted in the build folder
      * @param miningDurationSeconds
      *         the duration of the mining operation in [s]
      * @param scmKey
@@ -76,34 +68,22 @@ public ForensicsBuildAction(final Run<?, ?> owner, final RepositoryStatistics re
      * @param number
      *         unique number of the results (used as part of the serialization file name)
      */
-    public ForensicsBuildAction(final Run<?, ?> owner,
-            final RepositoryStatistics repositoryStatistics, final RepositoryStatistics deltaStatistics,
-            final int miningDurationSeconds, final String scmKey, final int number) {
-        this(owner, repositoryStatistics, deltaStatistics, true, miningDurationSeconds, scmKey, number);
-    }
-
     @VisibleForTesting
-    ForensicsBuildAction(final Run<?, ?> owner,
-            final RepositoryStatistics repositoryStatistics, final RepositoryStatistics deltaStatistics,
+    ForensicsBuildAction(final Run<?, ?> owner, final RepositoryStatistics repositoryStatistics,
             final boolean canSerialize, final int miningDurationSeconds, final String scmKey, final int number) {
         super(owner, repositoryStatistics, false);
 
+        numberOfFiles = repositoryStatistics.size();
         this.miningDurationSeconds = miningDurationSeconds;
         this.scmKey = scmKey;
 
         fileName = createFileName(number);
         urlName = createUrlName(number);
 
-        numberOfFiles = repositoryStatistics.size();
         totalLinesOfCode = repositoryStatistics.getTotalLinesOfCode();
         totalChurn = repositoryStatistics.getTotalChurn();
         commitStatistics = repositoryStatistics.getLatestStatistics();
 
-        deltaNumberOfFiles = deltaStatistics.size();
-        deltaTotalLinesOfCode = deltaStatistics.getTotalLinesOfCode();
-        deltaTotalChurn = deltaStatistics.getTotalChurn();
-        deltaCommitStatistics = deltaStatistics.getLatestStatistics();
-
         if (canSerialize) {
             createXmlStream().write(owner.getRootDir().toPath().resolve(fileName), repositoryStatistics);
         }
@@ -121,9 +101,6 @@ protected Object readResolve() {
         if (commitStatistics == null) {
             commitStatistics = new CommitStatistics();
         }
-        if (deltaCommitStatistics == null) {
-            deltaCommitStatistics = new CommitStatistics();
-        }
 
         return super.readResolve();
     }
@@ -182,14 +159,14 @@ public String getUrlName() {
         return urlName;
     }
 
-    public int getMiningDurationSeconds() {
-        return miningDurationSeconds;
-    }
-
     public int getNumberOfFiles() {
         return numberOfFiles;
     }
 
+    public int getMiningDurationSeconds() {
+        return miningDurationSeconds;
+    }
+
     public int getTotalLinesOfCode() {
         return totalLinesOfCode;
     }
@@ -202,27 +179,6 @@ public CommitStatistics getCommitStatistics() {
         return commitStatistics;
     }
 
-    public Run<?, ?> getReferenceBuild() {
-        return new ReferenceFinder().findReference(getOwner(), new FilteredLog(""))
-                .orElseThrow(() -> new NoSuchElementException("No reference build available"));
-    }
-
-    public int getDeltaNumberOfFiles() {
-        return deltaNumberOfFiles;
-    }
-
-    public int getDeltaTotalLinesOfCode() {
-        return deltaTotalLinesOfCode;
-    }
-
-    public int getDeltaTotalChurn() {
-        return deltaTotalChurn;
-    }
-
-    public CommitStatistics getDeltaCommitStatistics() {
-        return deltaCommitStatistics;
-    }
-
     public String getScmKey() {
         return scmKey;
     }
diff --git a/src/main/java/io/jenkins/plugins/forensics/miner/RepositoryMiner.java b/src/main/java/io/jenkins/plugins/forensics/miner/RepositoryMiner.java
index e016ebb9..2cba2ead 100644
--- a/src/main/java/io/jenkins/plugins/forensics/miner/RepositoryMiner.java
+++ b/src/main/java/io/jenkins/plugins/forensics/miner/RepositoryMiner.java
@@ -4,8 +4,6 @@
 
 import edu.hm.hafner.util.FilteredLog;
 
-import hudson.model.Run;
-
 /**
  * Obtains commit statistics for a source code repository. Computation of the commit statistics should be done
  * incrementally, if supported by the underlying SCM  (i.e., only commits new in the current build should be
@@ -17,10 +15,7 @@ public abstract class RepositoryMiner implements Serializable {
     private static final long serialVersionUID = -8878714986510536182L;
 
     /**
-     * Obtains commit statistics for a source code repository. If the {@code previousStatistics} are filled with results
-     * of a previous build, then an incremental mining will be started that only inspects the additional commits from
-     * the current build. Otherwise, the whole repository will be mined (which might take some time for large
-     * repositories).
+     * Obtains commit statistics for a source code repository.
      *
      * @param previousStatistics
      *         the repository statistics of the previous build - if there is no such build then an empty instance will
@@ -35,25 +30,6 @@ public abstract class RepositoryMiner implements Serializable {
     public abstract RepositoryStatistics mine(RepositoryStatistics previousStatistics, FilteredLog logger)
             throws InterruptedException;
 
-    /**
-     * Obtains delta commit statistics for a source code repository. Starts an incremental mining from the latest commit
-     * from the current build up to the common ancestor commit with the provided {@code referenceBuild}.
-     *
-     * @param referenceBuild
-     *         the reference build to use
-     * @param logger
-     *         the logger to use
-     *
-     * @return the statistics containing the commit statistics for the current build up to the common ancestor with the
-     *         reference build
-     * @throws InterruptedException
-     *         if the user canceled the processing
-     * @since 1.2.0
-     */
-    public RepositoryStatistics mine(final Run<?, ?> referenceBuild, final FilteredLog logger) throws InterruptedException {
-        return new RepositoryStatistics();
-    }
-
     /**
      * A repository miner that does nothing.
      */
diff --git a/src/main/java/io/jenkins/plugins/forensics/miner/RepositoryMinerStep.java b/src/main/java/io/jenkins/plugins/forensics/miner/RepositoryMinerStep.java
index ca4865da..a747a8da 100644
--- a/src/main/java/io/jenkins/plugins/forensics/miner/RepositoryMinerStep.java
+++ b/src/main/java/io/jenkins/plugins/forensics/miner/RepositoryMinerStep.java
@@ -1,7 +1,6 @@
 package io.jenkins.plugins.forensics.miner;
 
 import java.util.List;
-import java.util.Optional;
 
 import org.apache.commons.lang3.StringUtils;
 
@@ -26,7 +25,6 @@
 import hudson.tasks.Recorder;
 import jenkins.tasks.SimpleBuildStep;
 
-import io.jenkins.plugins.forensics.reference.ReferenceFinder;
 import io.jenkins.plugins.forensics.util.ScmResolver;
 import io.jenkins.plugins.util.BuildAction;
 import io.jenkins.plugins.util.LogHandler;
@@ -39,6 +37,8 @@
  *     <li>total number of different authors</li>
  *     <li>creation time</li>
  *     <li>last modification time</li>
+ *     <li>lines of code (from the commit details)</li>
+ *     <li>code churn (changed lines since created)</li>
  * </ul>
  * Stores the created statistics in a {@link RepositoryStatistics} instance. The result is attached to
  * a {@link Run} by registering a {@link ForensicsBuildAction}.
@@ -64,6 +64,7 @@ public RepositoryMinerStep() {
      *
      * @return this
      */
+    @SuppressWarnings("unused")
     @SuppressFBWarnings(value = "RCN_REDUNDANT_NULLCHECK_OF_NONNULL_VALUE", justification = "Deserialization of instances that do not have all fields yet")
     protected Object readResolve() {
         if (scm == null) {
@@ -108,60 +109,31 @@ private void mineRepositories(final Run<?, ?> run, final FilePath workspace, fin
             RepositoryMiner miner = MinerFactory.findMiner(repository, run, workspace, listener, logger);
             logHandler.log(logger);
 
-            RepositoryStatistics repositoryStatistics = previousBuildStatistics(run);
+            RepositoryStatistics repositoryStatistics = previousBuildStatistics(scm, run);
             RepositoryStatistics addedRepositoryStatistics = miner.mine(repositoryStatistics, logger);
 
-            RepositoryStatistics deltaStatistics = createDeltaStatistics(miner, run, logger);
-
             logHandler.log(logger);
             int miningDurationSeconds = (int) (1 + (System.nanoTime() - startOfMining) / 1_000_000_000L);
-            run.addAction(new ForensicsBuildAction(run, addedRepositoryStatistics, deltaStatistics,
-                    miningDurationSeconds, repository.getKey(), number++));
+            run.addAction(new ForensicsBuildAction(run, addedRepositoryStatistics, miningDurationSeconds,
+                    repository.getKey(), number++));
         }
     }
 
-    /**
-     * Returns the delta statistics of the current build compared to the best common ancestor commit with the reference
-     * build. If no reference build has been found, then an empty mining result is returned.
-     *
-     * @param miner
-     *         the miner
-     * @param run
-     *         the current build
-     * @param logger
-     *         the logger
-     *
-     * @return the delta statistics if a reference build with previous results has been found
-     * @throws InterruptedException
-     *         if the user stops the processing
-     */
-    private RepositoryStatistics createDeltaStatistics(final RepositoryMiner miner,
-            final Run<?, ?> run, final FilteredLog logger) throws InterruptedException {
-        Optional<Run<?, ?>> referenceBuild = new ReferenceFinder().findReference(run, logger);
-        if (referenceBuild.isPresent()) { // can't use streams due to checked exception
-            return miner.mine(referenceBuild.get(), logger);
-        }
-        return new RepositoryStatistics();
-    }
-
-    private RepositoryStatistics previousBuildStatistics(final Run<?, ?> run) {
+    private RepositoryStatistics previousBuildStatistics(final String repository, final Run<?, ?> run) {
         for (Run<?, ?> build = run.getPreviousBuild(); build != null; build = build.getPreviousBuild()) {
             List<ForensicsBuildAction> actions = build.getActions(ForensicsBuildAction.class);
             if (!actions.isEmpty()) {
-                return extractResult(actions).orElse(new RepositoryStatistics());
+                return actions.stream()
+                        .filter(a -> a.getScmKey().contains(repository))
+                        .findAny()
+                        .map(BuildAction::getResult)
+                        .orElse(new RepositoryStatistics());
             }
         }
 
         return new RepositoryStatistics();
     }
 
-    private Optional<RepositoryStatistics> extractResult(final List<ForensicsBuildAction> actions) {
-        return actions.stream()
-                .filter(a -> a.getScmKey().contains(scm))
-                .findAny()
-                .map(BuildAction::getResult);
-    }
-
     @Override
     public Descriptor getDescriptor() {
         return (Descriptor) super.getDescriptor();
diff --git a/src/main/resources/io/jenkins/plugins/forensics/miner/CommitStatisticsBuildAction/summary.jelly b/src/main/resources/io/jenkins/plugins/forensics/miner/CommitStatisticsBuildAction/summary.jelly
new file mode 100644
index 00000000..67ee3425
--- /dev/null
+++ b/src/main/resources/io/jenkins/plugins/forensics/miner/CommitStatisticsBuildAction/summary.jelly
@@ -0,0 +1,20 @@
+<?jelly escape-by-default='true'?>
+<j:jelly xmlns:j="jelly:core" xmlns:t="/lib/hudson">
+
+  <t:summary icon="/plugin/forensics-api/icons/diff-stat-48x48.png">
+    ${%title}: ${it.scmKey}
+    <j:set var="s" value="${it.commitStatistics}"/>
+    <ul>
+      <li>
+        Commits: ${s.commitCount} - compared to target branch of build <j:out value="${it.referenceBuild.referenceLink}"/>
+      </li>
+      <li>
+        Changed files: ${s.filesCount}
+      </li>
+      <li>
+        Changed lines: ${s.addedLines} added, ${s.deletedLines} deleted
+      </li>
+    </ul>
+  </t:summary>
+
+</j:jelly>
diff --git a/src/main/resources/io/jenkins/plugins/forensics/miner/CommitStatisticsBuildAction/summary.properties b/src/main/resources/io/jenkins/plugins/forensics/miner/CommitStatisticsBuildAction/summary.properties
new file mode 100644
index 00000000..3c096b16
--- /dev/null
+++ b/src/main/resources/io/jenkins/plugins/forensics/miner/CommitStatisticsBuildAction/summary.properties
@@ -0,0 +1 @@
+title=Commit Diff Statistics
diff --git a/src/main/webapp/icons/LICENSE.txt b/src/main/webapp/icons/LICENSE.txt
index 69fbbd56..b5d249c5 100644
--- a/src/main/webapp/icons/LICENSE.txt
+++ b/src/main/webapp/icons/LICENSE.txt
@@ -1,4 +1,4 @@
-License for FontAwesome icon: CC BY 4.0 License
+License for FontAwesome icons: CC BY 4.0 License
 https://fontawesome.com/license/free
 
 
diff --git a/src/main/webapp/icons/diff-stat-24x24.png b/src/main/webapp/icons/diff-stat-24x24.png
new file mode 100644
index 0000000000000000000000000000000000000000..566c7a08299465fa4dbcca749ecb4660386af404
GIT binary patch
literal 576
zcmV-G0>Ax<P)<h;3K|Lk000e1NJLTq000;O000;W1^@s6;CDUv00009a7bBm0001M
z0001M0S;eVQ2+n{8FWQhbW?9;ba!ELWdL_~cP?peYja~^aAhuUa%Y?FJQ@H10nJH7
zK~zYI&6BZ<6G0Tle=oOJNYYqnr3fB)jo2iOf|X#A?3TBs9w!zS!u<!<wu;DsNX}B5
zz)ltdXK@HtNu`Yz2L~2u#KM@BxU<h@_c)H#Og1Whu<Y>W<NNKKH!H@N9pDbI!h9vb
zJ>U0t9lQW|dH6HnwS)gYa2r?%u%fDOgCKZS6yrEPW39cCB*~jF3};0>ilUn$a>+Fu
zpjKAQvTQ>{_UiTe`XXV@01=U8g9~}ZVlWt-oy}&OA|k4K6+l(Dj4@*oN!so9V`EHp
zfVK9rh&(*8znz10G#Wjv(!tRYO(v6lU@d<h0Mu%=Hn5ha>4jFS^`i>lsDm&JEpPzP
z@Ap5eDysU)_x*z^!G%hP415E!EX%$x6As5ZIId2o(*?TAh69K(<}2`l{CMW*dj5Xz
z;GK!cb5BGzRdowE?f6j&d~xtyRMqZ6Ka??MUsXQ_L2!4TH;STLBC`9dA^$P`bwKGY
za#63>JMVekYT4d&Iz3zpFdPn7$K&xKP&&g#qjAGpTOH7BHq$tcw^jAj$vst7;2m(T
zGC)KWc=S6@6h**481jF2i>!#O8)G&cyw?D`5I{s;sOl5orGq^Mc76gXO{M-`dR5f`
O0000<MNUMnLSTYpNcy?}

literal 0
HcmV?d00001

diff --git a/src/main/webapp/icons/diff-stat-48x48.png b/src/main/webapp/icons/diff-stat-48x48.png
new file mode 100644
index 0000000000000000000000000000000000000000..4619f45f612ec4d0f8f29aea29c996ffee61390f
GIT binary patch
literal 796
zcmV+%1LOROP)<h;3K|Lk000e1NJLTq001xm001xu1^@s6R|5Hm00009a7bBm0002j
z0002j0V^kI>i_@%8FWQhbW?9;ba!ELWdL_~cP?peYja~^aAhuUa%Y?FJQ@H10;x$v
zK~!jg?V7)96hRn<pKosiu}GsNpa?>WH2y%rLPZD%O7Lza7Lw>6VPPu@F-q(rh>c(=
zXk!s}avUheLW!gh#8{|>or1ASa#3M3pT%8ba^8jPX7-kodz#yw*?sqWXTO=<nLR0&
z%e$i}x(@_E5AIOlvxr<P7K=|E>TbfT1%Da0!2<{|psG)dF^3#$uj5l~d4LKq>q=Ne
z`c(A@;ETvPVBVGXMtuIZ{A>^eXI%-GN~II3It!qxuJ7(TURuJf!jE%s7={-`<Twy@
zb#>hv8XEeZQe4|6mH`nN0}cX2QS<?LoI*^oh?_#vWIHq3z7KQ^WKF|P9ERbjh)gu7
z+P}78t-WiExm8#HZDnO;aAag;)n$-d(QFht3iNMvqKNbXeRakCz%F2U=b>$nW-0VL
zp<dM6+Z!bfCJ7DiKrWY?wAQ|AQ1uWv03afFRQ1KiN)h>y&*y)+53@N94HOE6Mc{dT
zxiO})VRt?Vf`5)_HEll%bqr)ptd}{elajqaWUc*@LOijFWgrNG(X;|dO53N97-J$J
z2YdpqJJdc5+yGEjBO;+IVG&u5qUh!D@bFieo}PYJn|!w$OP=Rl@I>S)u#|N)3Fxub
zP71)()YLxT_Xl0B9;oVh5m{TZ8OQCi%57i(SWRtOXp9-B)(1S#J6R|c-Z<2L2AqNa
zU=->Y$eNCUtZ91#ao<LFOsP~lX06>5_dL(@=4vy=O|;a&%*;%8rBazoa$Qv&18&xr
zw={(o78ZOGHk!4zyHR<oQ|Kq~n(Cw|4k{vV8&$N_KyAhDv`fvlAB8#wvZiAoYdQw9
zCbj2)h%Bip0IK@H7~}Gr@~PVIVww-KGB5%7DK6WDsijb{SbQ%cmsIs5)xX}jWD$4-
aT=@fZPsl`TI!>Pe0000<MNUMnLSTYx?OIX*

literal 0
HcmV?d00001


From 593165c21b52446e9324f532fc5c793872b12d0e Mon Sep 17 00:00:00 2001
From: Ulli Hafner <ullrich.hafner@gmail.com>
Date: Thu, 1 Jul 2021 00:34:46 +0200
Subject: [PATCH 4/7] Fix warnings.

---
 .../plugins/forensics/miner/CommitStatisticsBuildAction.java  | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/src/main/java/io/jenkins/plugins/forensics/miner/CommitStatisticsBuildAction.java b/src/main/java/io/jenkins/plugins/forensics/miner/CommitStatisticsBuildAction.java
index 66eca458..67c2989d 100644
--- a/src/main/java/io/jenkins/plugins/forensics/miner/CommitStatisticsBuildAction.java
+++ b/src/main/java/io/jenkins/plugins/forensics/miner/CommitStatisticsBuildAction.java
@@ -25,7 +25,7 @@
 public class CommitStatisticsBuildAction extends InvisibleAction implements LastBuildAction, RunAction2, Serializable {
     private static final long serialVersionUID = -263122257268060032L;
 
-    private Run<?, ?> owner;
+    private transient Run<?, ?> owner;
 
     private final String scmKey;
     private final CommitStatistics commitStatistics;
@@ -42,6 +42,8 @@ public class CommitStatisticsBuildAction extends InvisibleAction implements Last
      */
     public CommitStatisticsBuildAction(final Run<?, ?> owner,
             final String scmKey, final CommitStatistics commitStatistics) {
+        super();
+
         this.owner = owner;
         this.scmKey = scmKey;
         this.commitStatistics = commitStatistics;

From acc0fb2d662fa5617b854b282a9fd4bc9a9d98ff Mon Sep 17 00:00:00 2001
From: Ulli Hafner <ullrich.hafner@gmail.com>
Date: Thu, 1 Jul 2021 00:39:55 +0200
Subject: [PATCH 5/7] Suppress SpotBugs warning.

---
 .../plugins/forensics/miner/CommitStatisticsBuildAction.java    | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/src/main/java/io/jenkins/plugins/forensics/miner/CommitStatisticsBuildAction.java b/src/main/java/io/jenkins/plugins/forensics/miner/CommitStatisticsBuildAction.java
index 67c2989d..bb60b001 100644
--- a/src/main/java/io/jenkins/plugins/forensics/miner/CommitStatisticsBuildAction.java
+++ b/src/main/java/io/jenkins/plugins/forensics/miner/CommitStatisticsBuildAction.java
@@ -5,6 +5,7 @@
 import java.util.Collections;
 
 import edu.umd.cs.findbugs.annotations.CheckForNull;
+import edu.umd.cs.findbugs.annotations.SuppressFBWarnings;
 
 import hudson.model.Action;
 import hudson.model.InvisibleAction;
@@ -25,6 +26,7 @@
 public class CommitStatisticsBuildAction extends InvisibleAction implements LastBuildAction, RunAction2, Serializable {
     private static final long serialVersionUID = -263122257268060032L;
 
+    @SuppressFBWarnings(value = "SE", justification = "transient field owner ist restored using a Jenkins callback")
     private transient Run<?, ?> owner;
 
     private final String scmKey;

From 570ee9c542e012d4de876fbff22247dcff68a669 Mon Sep 17 00:00:00 2001
From: Ulli Hafner <ullrich.hafner@gmail.com>
Date: Thu, 1 Jul 2021 00:42:44 +0200
Subject: [PATCH 6/7] Restore old summary.

---
 .../miner/ForensicsBuildAction/summary.jelly  | 23 +++++--------------
 1 file changed, 6 insertions(+), 17 deletions(-)

diff --git a/src/main/resources/io/jenkins/plugins/forensics/miner/ForensicsBuildAction/summary.jelly b/src/main/resources/io/jenkins/plugins/forensics/miner/ForensicsBuildAction/summary.jelly
index 5eeb69fe..cf1b724d 100644
--- a/src/main/resources/io/jenkins/plugins/forensics/miner/ForensicsBuildAction/summary.jelly
+++ b/src/main/resources/io/jenkins/plugins/forensics/miner/ForensicsBuildAction/summary.jelly
@@ -3,29 +3,18 @@
 
   <t:summary icon="/plugin/forensics-api/icons/forensics-48x48.png">
     ${%title}: ${it.scmKey}
-    <j:set var="s" value="${it.commitStatistics}" />
-    <j:set var="d" value="${it.deltaCommitStatistics}" />
+    <j:set var="s" value="${it.result.latestStatistics}" />
     <ul>
       <li>
         <a href="${it.urlName}">${%summary(size(it.result))}</a>
-        (total lines of code: ${it.totalLinesOfCode}, total churn: ${it.totalChurn})
+        (total lines of code: ${it.result.totalLinesOfCode}, total churn: ${it.result.totalChurn})
       </li>
       <li>
-        New commits since previous build: ${s.commitCount}
-          (from ${s.authorCount} authors
-            in ${s.filesCount} files
-            with ${s.addedLines} added
-            and ${s.deletedLines} deleted lines)
+        New commits: ${s.commitCount} (from ${s.authorCount} authors in ${s.filesCount} files)
+      </li>
+      <li>
+        New lines: ${s.addedLines} added, ${s.deletedLines} deleted
       </li>
-      <j:if test="${it.deltaNumberOfFiles > 0}">
-        <li>
-          New commits since reference build <a href="${rootURL}/${it.referenceBuild.url}">${it.referenceBuild.displayName}</a>: ${d.commitCount}
-          (from ${d.authorCount} authors
-          in ${d.filesCount} files
-          with ${d.addedLines} added
-          and ${d.deletedLines} deleted lines)
-        </li>
-      </j:if>
       <li>
         Miner runtime: ${it.miningDurationSeconds} seconds
       </li>

From a8de01dd5e36c6ff3e0ccade787200280b905390 Mon Sep 17 00:00:00 2001
From: Ulli Hafner <ullrich.hafner@gmail.com>
Date: Fri, 2 Jul 2021 16:24:41 +0200
Subject: [PATCH 7/7] Improve layout of summary.

---
 .../miner/CommitStatisticsBuildAction/summary.jelly       | 8 +++++++-
 .../forensics/miner/ForensicsBuildAction/summary.jelly    | 2 +-
 2 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/src/main/resources/io/jenkins/plugins/forensics/miner/CommitStatisticsBuildAction/summary.jelly b/src/main/resources/io/jenkins/plugins/forensics/miner/CommitStatisticsBuildAction/summary.jelly
index 67ee3425..443e0098 100644
--- a/src/main/resources/io/jenkins/plugins/forensics/miner/CommitStatisticsBuildAction/summary.jelly
+++ b/src/main/resources/io/jenkins/plugins/forensics/miner/CommitStatisticsBuildAction/summary.jelly
@@ -6,7 +6,13 @@
     <j:set var="s" value="${it.commitStatistics}"/>
     <ul>
       <li>
-        Commits: ${s.commitCount} - compared to target branch of build <j:out value="${it.referenceBuild.referenceLink}"/>
+        Commits: ${s.commitCount} -
+        <j:choose>
+          <j:when test="${it.referenceBuild != null}">
+            compared to target branch of build <j:out value="${it.referenceBuild.referenceLink}"/>
+          </j:when>
+            compared to previous build
+        </j:choose>
       </li>
       <li>
         Changed files: ${s.filesCount}
diff --git a/src/main/resources/io/jenkins/plugins/forensics/miner/ForensicsBuildAction/summary.jelly b/src/main/resources/io/jenkins/plugins/forensics/miner/ForensicsBuildAction/summary.jelly
index cf1b724d..cf266e05 100644
--- a/src/main/resources/io/jenkins/plugins/forensics/miner/ForensicsBuildAction/summary.jelly
+++ b/src/main/resources/io/jenkins/plugins/forensics/miner/ForensicsBuildAction/summary.jelly
@@ -13,7 +13,7 @@
         New commits: ${s.commitCount} (from ${s.authorCount} authors in ${s.filesCount} files)
       </li>
       <li>
-        New lines: ${s.addedLines} added, ${s.deletedLines} deleted
+        Changed lines: ${s.addedLines} added, ${s.deletedLines} deleted
       </li>
       <li>
         Miner runtime: ${it.miningDurationSeconds} seconds