SONAR-4776 Load issues changelog at the begin of each module analysis

9 files changed, 191 insertions, 125 deletions

diff --git a/plugins/sonar-core-plugin/src/main/java/org/sonar/plugins/core/CorePlugin.java b/plugins/sonar-core-plugin/src/main/java/org/sonar/plugins/core/CorePlugin.java
index 265dcba65df..cd2f6d12bed 100644
--- a/plugins/sonar-core-plugin/src/main/java/org/sonar/plugins/core/CorePlugin.java
+++ b/plugins/sonar-core-plugin/src/main/java/org/sonar/plugins/core/CorePlugin.java
@@ -26,7 +26,6 @@ import org.sonar.api.config.PropertyDefinition;
 import org.sonar.api.resources.Java;
 import org.sonar.api.resources.Qualifiers;
 import org.sonar.batch.components.PastSnapshotFinder;
-import org.sonar.core.issue.IssueChangelogFinder;
 import org.sonar.core.technicaldebt.TechnicalDebtCalculator;
 import org.sonar.core.technicaldebt.TechnicalDebtConverter;
 import org.sonar.core.timemachine.Periods;
@@ -277,7 +276,6 @@ public final class CorePlugin extends SonarPlugin {
       UnresolvedIssuesStatusesWidget.class,
       IssueFilterWidget.class,
       org.sonar.api.issue.NoSonarFilter.class,
-      IssueChangelogFinder.class,
 
       // issue notifications
       SendIssueNotificationsPostJob.class,
@@ -396,7 +394,7 @@ public final class CorePlugin extends SonarPlugin {
         .type(PropertyType.BOOLEAN)
         .category(CoreProperties.CATEGORY_SECURITY)
         .build()
-      );
+    );
   }
 
 }
diff --git a/plugins/sonar-core-plugin/src/main/java/org/sonar/plugins/core/issue/InitialOpenIssuesSensor.java b/plugins/sonar-core-plugin/src/main/java/org/sonar/plugins/core/issue/InitialOpenIssuesSensor.java
index cff5ec73080..1a333be0f5a 100644
--- a/plugins/sonar-core-plugin/src/main/java/org/sonar/plugins/core/issue/InitialOpenIssuesSensor.java
+++ b/plugins/sonar-core-plugin/src/main/java/org/sonar/plugins/core/issue/InitialOpenIssuesSensor.java
@@ -25,6 +25,8 @@ import org.apache.ibatis.session.ResultHandler;
 import org.sonar.api.batch.Sensor;
 import org.sonar.api.batch.SensorContext;
 import org.sonar.api.resources.Project;
+import org.sonar.core.issue.db.IssueChangeDao;
+import org.sonar.core.issue.db.IssueChangeDto;
 import org.sonar.core.issue.db.IssueDao;
 import org.sonar.core.issue.db.IssueDto;
 
@@ -38,10 +40,12 @@ public class InitialOpenIssuesSensor implements Sensor {
 
   private final InitialOpenIssuesStack initialOpenIssuesStack;
   private final IssueDao issueDao;
+  private final IssueChangeDao issueChangeDao;
 
-  public InitialOpenIssuesSensor(InitialOpenIssuesStack initialOpenIssuesStack, IssueDao issueDao) {
+  public InitialOpenIssuesSensor(InitialOpenIssuesStack initialOpenIssuesStack, IssueDao issueDao, IssueChangeDao issueChangeDao) {
     this.initialOpenIssuesStack = initialOpenIssuesStack;
     this.issueDao = issueDao;
+    this.issueChangeDao = issueChangeDao;
   }
 
   @Override
@@ -63,6 +67,14 @@ public class InitialOpenIssuesSensor implements Sensor {
         initialOpenIssuesStack.addIssue(dto);
       }
     });
+
+    issueChangeDao.selectChangelogOnNonClosedIssuesByModuleAndType(project.getId(), new ResultHandler() {
+      @Override
+      public void handleResult(ResultContext rc) {
+        IssueChangeDto dto = (IssueChangeDto) rc.getResultObject();
+        initialOpenIssuesStack.addChangelog(dto);
+      }
+    });
   }
 
   @Override
diff --git a/plugins/sonar-core-plugin/src/main/java/org/sonar/plugins/core/issue/InitialOpenIssuesStack.java b/plugins/sonar-core-plugin/src/main/java/org/sonar/plugins/core/issue/InitialOpenIssuesStack.java
index d3a4c969c27..4646224dd03 100644
--- a/plugins/sonar-core-plugin/src/main/java/org/sonar/plugins/core/issue/InitialOpenIssuesStack.java
+++ b/plugins/sonar-core-plugin/src/main/java/org/sonar/plugins/core/issue/InitialOpenIssuesStack.java
@@ -20,44 +20,66 @@
 
 package org.sonar.plugins.core.issue;
 
-import com.google.common.collect.Lists;
+import edu.emory.mathcs.backport.java.util.Collections;
 import org.sonar.api.BatchExtension;
 import org.sonar.api.batch.InstantiationStrategy;
 import org.sonar.batch.index.Cache;
 import org.sonar.batch.index.Caches;
+import org.sonar.core.issue.db.IssueChangeDto;
 import org.sonar.core.issue.db.IssueDto;
 
+import java.util.ArrayList;
 import java.util.List;
 
+import static com.google.common.collect.Lists.newArrayList;
+
 @InstantiationStrategy(InstantiationStrategy.PER_BATCH)
 public class InitialOpenIssuesStack implements BatchExtension {
 
-  private final Cache<String, IssueDto> cache;
+  private final Cache<String, IssueDto> issuesCache;
+  private final Cache<String, ArrayList<IssueChangeDto>> issuesChangelogCache;
 
   public InitialOpenIssuesStack(Caches caches) {
-    cache = caches.createCache("last-open-issues");
+    issuesCache = caches.createCache("last-open-issues");
+    issuesChangelogCache = caches.createCache("issues-changelog");
   }
 
   public InitialOpenIssuesStack addIssue(IssueDto issueDto) {
-    cache.put(issueDto.getComponentKey(), issueDto.getKee(), issueDto);
+    issuesCache.put(issueDto.getComponentKey(), issueDto.getKee(), issueDto);
     return this;
   }
 
-  public List<IssueDto> selectAndRemove(String componentKey) {
-    Iterable<IssueDto> issues = cache.values(componentKey);
-    List<IssueDto> result = Lists.newArrayList();
+  public List<IssueDto> selectAndRemoveIssues(String componentKey) {
+    Iterable<IssueDto> issues = issuesCache.values(componentKey);
+    List<IssueDto> result = newArrayList();
     for (IssueDto issue : issues) {
       result.add(issue);
     }
-    cache.clear(componentKey);
+    issuesCache.clear(componentKey);
     return result;
   }
 
-  public Iterable<IssueDto> selectAll() {
-    return cache.allValues();
+  public Iterable<IssueDto> selectAllIssues() {
+    return issuesCache.allValues();
+  }
+
+  public InitialOpenIssuesStack addChangelog(IssueChangeDto issueChangeDto) {
+    ArrayList<IssueChangeDto> changeDtos = issuesChangelogCache.get(issueChangeDto.getIssueKey());
+    if (changeDtos == null) {
+      changeDtos = newArrayList();
+    }
+    changeDtos.add(issueChangeDto);
+    issuesChangelogCache.put(issueChangeDto.getIssueKey(), changeDtos);
+    return this;
+  }
+
+  public List<IssueChangeDto> selectChangelog(String issueKey) {
+    List<IssueChangeDto> changeDtos = issuesChangelogCache.get(issueKey);
+    return changeDtos != null ? changeDtos : Collections.emptyList();
   }
 
   public void clear() {
-    cache.clearAll();
+    issuesCache.clearAll();
+    issuesChangelogCache.clearAll();
   }
 }
diff --git a/plugins/sonar-core-plugin/src/main/java/org/sonar/plugins/core/issue/IssueTrackingDecorator.java b/plugins/sonar-core-plugin/src/main/java/org/sonar/plugins/core/issue/IssueTrackingDecorator.java
index d244dce5501..90603e96ce7 100644
--- a/plugins/sonar-core-plugin/src/main/java/org/sonar/plugins/core/issue/IssueTrackingDecorator.java
+++ b/plugins/sonar-core-plugin/src/main/java/org/sonar/plugins/core/issue/IssueTrackingDecorator.java
@@ -43,6 +43,7 @@ import org.sonar.api.utils.KeyValueFormat;
 import org.sonar.batch.issue.IssueCache;
 import org.sonar.batch.scan.LastSnapshots;
 import org.sonar.core.issue.IssueUpdater;
+import org.sonar.core.issue.db.IssueChangeDto;
 import org.sonar.core.issue.db.IssueDto;
 import org.sonar.core.issue.workflow.IssueWorkflow;
 
@@ -110,7 +111,7 @@ public class IssueTrackingDecorator implements Decorator {
     // issues = all the issues created by rule engines during this module scan and not excluded by filters
 
     // all the issues that are not closed in db before starting this module scan, including manual issues
-    Collection<IssueDto> dbOpenIssues = initialOpenIssues.selectAndRemove(resource.getEffectiveKey());
+    Collection<IssueDto> dbOpenIssues = initialOpenIssues.selectAndRemoveIssues(resource.getEffectiveKey());
 
     SourceHashHolder sourceHashHolder = new SourceHashHolder(index, lastSnapshots, resource);
 
@@ -160,6 +161,12 @@ public class IssueTrackingDecorator implements Decorator {
         issue.setAttributes(KeyValueFormat.parse(ref.getIssueAttributes()));
       }
 
+      // populate existing changelog
+      Collection<IssueChangeDto> issueChangeDtos = initialOpenIssues.selectChangelog(issue.key());
+      for (IssueChangeDto issueChangeDto : issueChangeDtos) {
+        issue.addChange(issueChangeDto.toFieldDiffs());
+      }
+
       // fields to update with current values
       if (ref.isManualSeverity()) {
         issue.setManualSeverity(true);
@@ -188,7 +195,7 @@ public class IssueTrackingDecorator implements Decorator {
   }
 
   private void addIssuesOnDeletedComponents(Collection<DefaultIssue> issues) {
-    for (IssueDto deadDto : initialOpenIssues.selectAll()) {
+    for (IssueDto deadDto : initialOpenIssues.selectAllIssues()) {
       DefaultIssue dead = deadDto.toDefaultIssue();
       updateUnmatchedIssue(dead, true);
       issues.add(dead);
diff --git a/plugins/sonar-core-plugin/src/main/java/org/sonar/plugins/core/technicaldebt/NewTechnicalDebtDecorator.java b/plugins/sonar-core-plugin/src/main/java/org/sonar/plugins/core/technicaldebt/NewTechnicalDebtDecorator.java
index 7e003efd5c6..3f22b68a80a 100644
--- a/plugins/sonar-core-plugin/src/main/java/org/sonar/plugins/core/technicaldebt/NewTechnicalDebtDecorator.java
+++ b/plugins/sonar-core-plugin/src/main/java/org/sonar/plugins/core/technicaldebt/NewTechnicalDebtDecorator.java
@@ -21,8 +21,6 @@
 package org.sonar.plugins.core.technicaldebt;
 
 import com.google.common.collect.ImmutableList;
-import com.google.common.collect.Lists;
-import com.google.common.collect.Multimap;
 import org.apache.commons.lang.time.DateUtils;
 import org.sonar.api.batch.*;
 import org.sonar.api.component.ResourcePerspectives;
@@ -39,7 +37,6 @@ import org.sonar.api.resources.Project;
 import org.sonar.api.resources.Resource;
 import org.sonar.batch.components.Period;
 import org.sonar.batch.components.TimeMachineConfiguration;
-import org.sonar.core.issue.IssueChangelogFinder;
 import org.sonar.core.issue.IssueUpdater;
 import org.sonar.core.technicaldebt.TechnicalDebtConverter;
 
@@ -58,14 +55,11 @@ public final class NewTechnicalDebtDecorator implements Decorator {
 
   private final ResourcePerspectives perspectives;
   private final TimeMachineConfiguration timeMachineConfiguration;
-  private final IssueChangelogFinder changelogFinder;
   private final TechnicalDebtConverter technicalDebtConverter;
 
-  public NewTechnicalDebtDecorator(ResourcePerspectives perspectives, TimeMachineConfiguration timeMachineConfiguration, IssueChangelogFinder changelogFinder,
-                                   TechnicalDebtConverter technicalDebtConverter) {
+  public NewTechnicalDebtDecorator(ResourcePerspectives perspectives, TimeMachineConfiguration timeMachineConfiguration, TechnicalDebtConverter technicalDebtConverter) {
     this.perspectives = perspectives;
     this.timeMachineConfiguration = timeMachineConfiguration;
-    this.changelogFinder = changelogFinder;
     this.technicalDebtConverter = technicalDebtConverter;
   }
 
@@ -84,16 +78,15 @@ public final class NewTechnicalDebtDecorator implements Decorator {
     Issuable issuable = perspectives.as(Issuable.class, resource);
     if (issuable != null && shouldSaveNewMetrics(context)) {
       List<Issue> issues = newArrayList(issuable.issues());
-      Multimap<Issue, FieldDiffs> changelogList = changelogFinder.findByIssues(issues);
-      saveMeasures(context, issues, changelogList);
+      saveMeasures(context, issues);
     }
   }
 
-  private void saveMeasures(DecoratorContext context, Collection<Issue> issues, Multimap<Issue, FieldDiffs> changelogList) {
+  private void saveMeasures(DecoratorContext context, Collection<Issue> issues) {
     Measure measure = new Measure(CoreMetrics.NEW_TECHNICAL_DEBT);
     for (Period period : timeMachineConfiguration.periods()) {
       Date periodDate = period.getDate() != null ? DateUtils.addSeconds(period.getDate(), 1) : null;
-      double value = calculateNewTechnicalDebtValue(issues, changelogList, periodDate);
+      double value = calculateNewTechnicalDebtValue(issues, periodDate);
       Collection<Measure> children = context.getChildrenMeasures(measure.getMetric());
       double sum = MeasureUtils.sumOnVariation(true, period.getIndex(), children) + value;
       measure.setVariation(period.getIndex(), sum);
@@ -101,11 +94,11 @@ public final class NewTechnicalDebtDecorator implements Decorator {
     context.saveMeasure(measure);
   }
 
-  private Double calculateNewTechnicalDebtValue(Collection<Issue> issues, Multimap<Issue, FieldDiffs> changelogList, @Nullable Date periodDate){
+  private Double calculateNewTechnicalDebtValue(Collection<Issue> issues, @Nullable Date periodDate) {
     double value = 0;
     for (Issue issue : issues) {
       WorkDayDuration currentTechnicalDebt = ((DefaultIssue) issue).technicalDebt();
-      List<FieldDiffs> technicalDebtChangelog = changesOnField(IssueUpdater.TECHNICAL_DEBT, changelogList.get(issue));
+      List<FieldDiffs> technicalDebtChangelog = changesOnField(IssueUpdater.TECHNICAL_DEBT, ((DefaultIssue) issue).changes());
       if (technicalDebtChangelog.isEmpty()) {
         if (isAfter(issue.creationDate(), periodDate)) {
           value += technicalDebtConverter.toDays(currentTechnicalDebt);
@@ -120,8 +113,14 @@ public final class NewTechnicalDebtDecorator implements Decorator {
   private Double calculateNewTechnicalDebtValueFromChangelog(WorkDayDuration currentTechnicalDebt, List<FieldDiffs> technicalDebtChangelog, Date periodDate) {
     double currentTechnicalDebtValue = technicalDebtConverter.toDays(currentTechnicalDebt);
 
-    // Changelog have to be sorted from oldest to newest to catch oldest value just before the period date -> By default it's sorted from newest to oldest
-    for (FieldDiffs fieldDiffs : Lists.reverse(technicalDebtChangelog)) {
+    // Changelog have to be sorted from oldest to newest to catch oldest value just before the period date
+    Collections.sort(technicalDebtChangelog, new Comparator<FieldDiffs>() {
+      @Override
+      public int compare(FieldDiffs fieldDiffs, FieldDiffs fieldDiffs2) {
+        return fieldDiffs.createdAt().compareTo(fieldDiffs2.createdAt());
+      }
+    });
+    for (FieldDiffs fieldDiffs : technicalDebtChangelog) {
       if (isAfter(fieldDiffs.createdAt(), periodDate)) {
         WorkDayDuration pastTechnicalDebt = newValue(IssueUpdater.TECHNICAL_DEBT, fieldDiffs);
         double pastTechnicalDebtValue = technicalDebtConverter.toDays(pastTechnicalDebt);
diff --git a/plugins/sonar-core-plugin/src/test/java/org/sonar/plugins/core/issue/InitialOpenIssuesSensorTest.java b/plugins/sonar-core-plugin/src/test/java/org/sonar/plugins/core/issue/InitialOpenIssuesSensorTest.java
index 814da65f220..e6c1b2c30d7 100644
--- a/plugins/sonar-core-plugin/src/test/java/org/sonar/plugins/core/issue/InitialOpenIssuesSensorTest.java
+++ b/plugins/sonar-core-plugin/src/test/java/org/sonar/plugins/core/issue/InitialOpenIssuesSensorTest.java
@@ -22,8 +22,8 @@ package org.sonar.plugins.core.issue;
 import org.apache.ibatis.session.ResultHandler;
 import org.junit.Test;
 import org.sonar.api.resources.Project;
+import org.sonar.core.issue.db.IssueChangeDao;
 import org.sonar.core.issue.db.IssueDao;
-import org.sonar.core.issue.db.IssueDto;
 
 import static org.fest.assertions.Assertions.assertThat;
 import static org.mockito.Matchers.any;
@@ -35,7 +35,9 @@ public class InitialOpenIssuesSensorTest {
 
   InitialOpenIssuesStack stack = mock(InitialOpenIssuesStack.class);
   IssueDao issueDao = mock(IssueDao.class);
-  InitialOpenIssuesSensor sensor = new InitialOpenIssuesSensor(stack, issueDao);
+  IssueChangeDao issueChangeDao = mock(IssueChangeDao.class);
+
+  InitialOpenIssuesSensor sensor = new InitialOpenIssuesSensor(stack, issueDao, issueChangeDao);
 
   @Test
   public void should_select_module_open_issues() {
@@ -47,6 +49,15 @@ public class InitialOpenIssuesSensorTest {
   }
 
   @Test
+  public void should_select_module_open_issues_changelog() {
+    Project project = new Project("key");
+    project.setId(1);
+    sensor.analyse(project, null);
+
+    verify(issueChangeDao).selectChangelogOnNonClosedIssuesByModuleAndType(eq(1), any(ResultHandler.class));
+  }
+
+  @Test
   public void test_toString() throws Exception {
     assertThat(sensor.toString()).isEqualTo("InitialOpenIssuesSensor");
 
diff --git a/plugins/sonar-core-plugin/src/test/java/org/sonar/plugins/core/issue/InitialOpenIssuesStackTest.java b/plugins/sonar-core-plugin/src/test/java/org/sonar/plugins/core/issue/InitialOpenIssuesStackTest.java
index c6fbeaf5cb5..3f9144bd824 100644
--- a/plugins/sonar-core-plugin/src/test/java/org/sonar/plugins/core/issue/InitialOpenIssuesStackTest.java
+++ b/plugins/sonar-core-plugin/src/test/java/org/sonar/plugins/core/issue/InitialOpenIssuesStackTest.java
@@ -31,6 +31,7 @@ import org.sonar.batch.bootstrap.BootstrapProperties;
 import org.sonar.batch.bootstrap.BootstrapSettings;
 import org.sonar.batch.bootstrap.TempFolderProvider;
 import org.sonar.batch.index.Caches;
+import org.sonar.core.issue.db.IssueChangeDto;
 import org.sonar.core.issue.db.IssueDto;
 
 import java.io.IOException;
@@ -69,48 +70,74 @@ public class InitialOpenIssuesStackTest {
   }
 
   @Test
-  public void should_get_and_remove() {
+  public void get_and_remove_issues() {
     IssueDto issueDto = new IssueDto().setComponentKey_unit_test_only("org.struts.Action").setKee("ISSUE-1");
     stack.addIssue(issueDto);
 
-    List<IssueDto> issueDtos = stack.selectAndRemove("org.struts.Action");
+    List<IssueDto> issueDtos = stack.selectAndRemoveIssues("org.struts.Action");
     assertThat(issueDtos).hasSize(1);
     assertThat(issueDtos.get(0).getKee()).isEqualTo("ISSUE-1");
 
-    assertThat(stack.selectAll()).isEmpty();
+    assertThat(stack.selectAllIssues()).isEmpty();
   }
 
   @Test
-  public void should_get_and_remove_with_many_issues_on_same_resource() {
+  public void get_and_remove_with_many_issues_on_same_resource() {
     stack.addIssue(new IssueDto().setComponentKey_unit_test_only("org.struts.Action").setKee("ISSUE-1"));
     stack.addIssue(new IssueDto().setComponentKey_unit_test_only("org.struts.Action").setKee("ISSUE-2"));
 
-    List<IssueDto> issueDtos = stack.selectAndRemove("org.struts.Action");
+    List<IssueDto> issueDtos = stack.selectAndRemoveIssues("org.struts.Action");
     assertThat(issueDtos).hasSize(2);
 
-    assertThat(stack.selectAll()).isEmpty();
+    assertThat(stack.selectAllIssues()).isEmpty();
   }
 
   @Test
-  public void should_do_nothing_if_resource_not_found() {
+  public void get_and_remove_do_nothing_if_resource_not_found() {
     stack.addIssue(new IssueDto().setComponentKey_unit_test_only("org.struts.Action").setKee("ISSUE-1"));
 
-    List<IssueDto> issueDtos = stack.selectAndRemove("Other");
+    List<IssueDto> issueDtos = stack.selectAndRemoveIssues("Other");
     assertThat(issueDtos).hasSize(0);
 
-    assertThat(stack.selectAll()).hasSize(1);
+    assertThat(stack.selectAllIssues()).hasSize(1);
   }
 
   @Test
-  public void should_clear() {
+  public void select_changelog() {
+    stack.addChangelog(new IssueChangeDto().setKey("CHANGE-1").setIssueKey("ISSUE-1"));
+    stack.addChangelog(new IssueChangeDto().setKey("CHANGE-2").setIssueKey("ISSUE-1"));
+
+    List<IssueChangeDto> issueChangeDtos = stack.selectChangelog("ISSUE-1");
+    assertThat(issueChangeDtos).hasSize(2);
+    assertThat(issueChangeDtos.get(0).getKey()).isEqualTo("CHANGE-1");
+    assertThat(issueChangeDtos.get(1).getKey()).isEqualTo("CHANGE-2");
+  }
+
+  @Test
+  public void return_empty_changelog() {
+    assertThat(stack.selectChangelog("ISSUE-1")).isEmpty();
+  }
+
+  @Test
+  public void clear_issues() {
     stack.addIssue(new IssueDto().setComponentKey_unit_test_only("org.struts.Action").setKee("ISSUE-1"));
 
-    assertThat(stack.selectAll()).hasSize(1);
+    assertThat(stack.selectAllIssues()).hasSize(1);
 
     // issues are not removed
-    assertThat(stack.selectAll()).hasSize(1);
+    assertThat(stack.selectAllIssues()).hasSize(1);
+
+    stack.clear();
+    assertThat(stack.selectAllIssues()).hasSize(0);
+  }
+
+  @Test
+  public void clear_issues_changelog() {
+    stack.addChangelog(new IssueChangeDto().setKey("CHANGE-1").setIssueKey("ISSUE-1"));
+
+    assertThat(stack.selectChangelog("ISSUE-1")).hasSize(1);
 
     stack.clear();
-    assertThat(stack.selectAll()).hasSize(0);
+    assertThat(stack.selectChangelog("ISSUE-1")).isNull();
   }
 }
diff --git a/plugins/sonar-core-plugin/src/test/java/org/sonar/plugins/core/issue/IssueTrackingDecoratorTest.java b/plugins/sonar-core-plugin/src/test/java/org/sonar/plugins/core/issue/IssueTrackingDecoratorTest.java
index ddf259cacd8..9a573b3d62a 100644
--- a/plugins/sonar-core-plugin/src/test/java/org/sonar/plugins/core/issue/IssueTrackingDecoratorTest.java
+++ b/plugins/sonar-core-plugin/src/test/java/org/sonar/plugins/core/issue/IssueTrackingDecoratorTest.java
@@ -40,6 +40,7 @@ import org.sonar.api.rules.RuleFinder;
 import org.sonar.batch.issue.IssueCache;
 import org.sonar.batch.scan.LastSnapshots;
 import org.sonar.core.issue.IssueUpdater;
+import org.sonar.core.issue.db.IssueChangeDto;
 import org.sonar.core.issue.db.IssueDto;
 import org.sonar.core.issue.workflow.IssueWorkflow;
 import org.sonar.core.persistence.AbstractDaoTestCase;
@@ -113,7 +114,7 @@ public class IssueTrackingDecoratorTest extends AbstractDaoTestCase {
     // INPUT : one issue, no open issues during previous scan, no filtering
     when(issueCache.byComponent("struts:Action.java")).thenReturn(Arrays.asList(issue));
     List<IssueDto> dbIssues = Collections.emptyList();
-    when(initialOpenIssues.selectAndRemove("struts:Action.java")).thenReturn(dbIssues);
+    when(initialOpenIssues.selectAndRemoveIssues("struts:Action.java")).thenReturn(dbIssues);
 
     decorator.doDecorate(file);
 
@@ -486,7 +487,7 @@ public class IssueTrackingDecoratorTest extends AbstractDaoTestCase {
     DefaultIssue openIssue = new DefaultIssue();
     when(issueCache.byComponent("struts")).thenReturn(Arrays.asList(openIssue));
     IssueDto deadIssue = new IssueDto().setKee("ABCDE").setResolution(null).setStatus("OPEN").setRuleKey_unit_test_only("squid", "AvoidCycle");
-    when(initialOpenIssues.selectAll()).thenReturn(Arrays.asList(deadIssue));
+    when(initialOpenIssues.selectAllIssues()).thenReturn(Arrays.asList(deadIssue));
 
     decorator.doDecorate(project);
 
@@ -537,4 +538,21 @@ public class IssueTrackingDecoratorTest extends AbstractDaoTestCase {
     assertThat(issue.severity()).isEqualTo("MAJOR");
     verify(updater, never()).setPastSeverity(eq(issue), anyString(), any(IssueChangeContext.class));
   }
+
+  @Test
+  public void merge_issue_changelog_with_previous_changelog() throws Exception {
+    when(initialOpenIssues.selectChangelog("ABCDE")).thenReturn(newArrayList(new IssueChangeDto().setIssueKey("ABCD")));
+
+    IssueDto previousIssue = new IssueDto().setKee("ABCDE").setResolution(null).setStatus("OPEN").setRuleKey_unit_test_only("squid", "AvoidCycle")
+      .setLine(10).setMessage("Message").setEffortToFix(1.5).setTechnicalDebt(1L);
+    DefaultIssue issue = new DefaultIssue();
+
+    IssueTrackingResult trackingResult = mock(IssueTrackingResult.class);
+    when(trackingResult.matched()).thenReturn(newArrayList(issue));
+    when(trackingResult.matching(eq(issue))).thenReturn(previousIssue);
+    decorator.mergeMatched(trackingResult);
+
+    assertThat(issue.changes()).hasSize(1);
+  }
+
 }
diff --git a/plugins/sonar-core-plugin/src/test/java/org/sonar/plugins/core/technicaldebt/NewTechnicalDebtDecoratorTest.java b/plugins/sonar-core-plugin/src/test/java/org/sonar/plugins/core/technicaldebt/NewTechnicalDebtDecoratorTest.java
index 12fe60f2ff3..309dd77b584 100644
--- a/plugins/sonar-core-plugin/src/test/java/org/sonar/plugins/core/technicaldebt/NewTechnicalDebtDecoratorTest.java
+++ b/plugins/sonar-core-plugin/src/test/java/org/sonar/plugins/core/technicaldebt/NewTechnicalDebtDecoratorTest.java
@@ -43,7 +43,6 @@ import org.sonar.api.resources.Resource;
 import org.sonar.api.test.IsMeasure;
 import org.sonar.batch.components.Period;
 import org.sonar.batch.components.TimeMachineConfiguration;
-import org.sonar.core.issue.IssueChangelogFinder;
 import org.sonar.core.technicaldebt.TechnicalDebtConverter;
 
 import java.util.Calendar;
@@ -51,7 +50,6 @@ import java.util.Date;
 
 import static com.google.common.collect.Lists.newArrayList;
 import static org.fest.assertions.Assertions.assertThat;
-import static org.mockito.Matchers.anyCollection;
 import static org.mockito.Matchers.argThat;
 import static org.mockito.Mockito.*;
 
@@ -73,9 +71,6 @@ public class NewTechnicalDebtDecoratorTest {
   DecoratorContext context;
 
   @Mock
-  IssueChangelogFinder changelogFinder;
-
-  @Mock
   TechnicalDebtConverter technicalDebtConverter;
 
   Date rightNow;
@@ -109,7 +104,7 @@ public class NewTechnicalDebtDecoratorTest {
 
     when(timeMachineConfiguration.periods()).thenReturn(newArrayList(new Period(1, fiveDaysAgo, fiveDaysAgo), new Period(2, tenDaysAgo, tenDaysAgo)));
 
-    decorator = new NewTechnicalDebtDecorator(perspectives, timeMachineConfiguration, changelogFinder, technicalDebtConverter);
+    decorator = new NewTechnicalDebtDecorator(perspectives, timeMachineConfiguration, technicalDebtConverter);
   }
 
   @Test
@@ -124,17 +119,16 @@ public class NewTechnicalDebtDecoratorTest {
 
   @Test
   public void save_on_one_issue_with_changelog() {
-    Issue issue = new DefaultIssue().setKey("A").setCreationDate(fiveDaysAgo).setTechnicalDebt(fiveDaysDebt);
+    Issue issue = new DefaultIssue().setKey("A").setCreationDate(fiveDaysAgo).setTechnicalDebt(fiveDaysDebt).setChanges(
+      newArrayList(
+        new FieldDiffs().setDiff("technicalDebt", twoDaysDebt, fiveDaysDebt).setCreatedAt(rightNow),
+        new FieldDiffs().setDiff("technicalDebt", oneDaysDebt, twoDaysDebt).setCreatedAt(fourDaysAgo),
+        new FieldDiffs().setDiff("technicalDebt", null, oneDaysDebt).setCreatedAt(nineDaysAgo)
+      )
+    );
     when(issuable.issues()).thenReturn(newArrayList(issue));
 
     Multimap<Issue, FieldDiffs> changelogList = ArrayListMultimap.create();
-    // Changes should be sorted from newest to oldest
-    changelogList.putAll(issue, newArrayList(
-      new FieldDiffs().setDiff("technicalDebt", twoDaysDebt, fiveDaysDebt).setCreatedAt(rightNow),
-      new FieldDiffs().setDiff("technicalDebt", oneDaysDebt, twoDaysDebt).setCreatedAt(fourDaysAgo),
-      new FieldDiffs().setDiff("technicalDebt", null, oneDaysDebt).setCreatedAt(nineDaysAgo)
-    ));
-    when(changelogFinder.findByIssues(anyCollection())).thenReturn(changelogList);
 
     decorator.decorate(resource, context);
 
@@ -144,18 +138,15 @@ public class NewTechnicalDebtDecoratorTest {
 
   @Test
   public void save_on_one_issue_with_changelog_having_null_value() {
-    Issue issue = new DefaultIssue().setKey("A").setCreationDate(fiveDaysAgo).setTechnicalDebt(fiveDaysDebt);
+    Issue issue = new DefaultIssue().setKey("A").setCreationDate(fiveDaysAgo).setTechnicalDebt(fiveDaysDebt).setChanges(
+      newArrayList(
+        new FieldDiffs().setDiff("technicalDebt", null, fiveDaysDebt).setCreatedAt(rightNow),
+        new FieldDiffs().setDiff("technicalDebt", oneDaysDebt, null).setCreatedAt(fourDaysAgo),
+        new FieldDiffs().setDiff("technicalDebt", null, oneDaysDebt).setCreatedAt(nineDaysAgo)
+      )
+    );
     when(issuable.issues()).thenReturn(newArrayList(issue));
 
-    Multimap<Issue, FieldDiffs> changelogList = ArrayListMultimap.create();
-    // Changes should be sorted from newest to oldest
-    changelogList.putAll(issue, newArrayList(
-      new FieldDiffs().setDiff("technicalDebt", null, fiveDaysDebt).setCreatedAt(rightNow),
-      new FieldDiffs().setDiff("technicalDebt", oneDaysDebt, null).setCreatedAt(fourDaysAgo),
-      new FieldDiffs().setDiff("technicalDebt", null, oneDaysDebt).setCreatedAt(nineDaysAgo)
-    ));
-    when(changelogFinder.findByIssues(anyCollection())).thenReturn(changelogList);
-
     decorator.decorate(resource, context);
 
     // remember : period1 is 5daysAgo, period2 is 10daysAgo
@@ -166,18 +157,15 @@ public class NewTechnicalDebtDecoratorTest {
   public void save_on_one_issue_with_changelog_and_periods_have_no_dates() {
     when(timeMachineConfiguration.periods()).thenReturn(newArrayList(new Period(1, null, null), new Period(2, null, null)));
 
-    Issue issue = new DefaultIssue().setKey("A").setCreationDate(fiveDaysAgo).setTechnicalDebt(fiveDaysDebt);
+    Issue issue = new DefaultIssue().setKey("A").setCreationDate(fiveDaysAgo).setTechnicalDebt(fiveDaysDebt).setChanges(
+      newArrayList(
+        new FieldDiffs().setDiff("technicalDebt", null, fiveDaysDebt).setCreatedAt(rightNow),
+        new FieldDiffs().setDiff("technicalDebt", oneDaysDebt, null).setCreatedAt(fourDaysAgo),
+        new FieldDiffs().setDiff("technicalDebt", null, oneDaysDebt).setCreatedAt(nineDaysAgo)
+      )
+    );
     when(issuable.issues()).thenReturn(newArrayList(issue));
 
-    Multimap<Issue, FieldDiffs> changelogList = ArrayListMultimap.create();
-    // Changes should be sorted from newest to oldest
-    changelogList.putAll(issue, newArrayList(
-      new FieldDiffs().setDiff("technicalDebt", null, fiveDaysDebt).setCreatedAt(rightNow),
-      new FieldDiffs().setDiff("technicalDebt", oneDaysDebt, null).setCreatedAt(fourDaysAgo),
-      new FieldDiffs().setDiff("technicalDebt", null, oneDaysDebt).setCreatedAt(nineDaysAgo)
-    ));
-    when(changelogFinder.findByIssues(anyCollection())).thenReturn(changelogList);
-
     decorator.decorate(resource, context);
 
     // remember : period1 is 5daysAgo, period2 is 10daysAgo
@@ -186,23 +174,21 @@ public class NewTechnicalDebtDecoratorTest {
 
   @Test
   public void save_on_issues_with_changelog() {
-    Issue issue1 = new DefaultIssue().setKey("A").setCreationDate(fiveDaysAgo).setTechnicalDebt(fiveDaysDebt);
-    Issue issue2 = new DefaultIssue().setKey("B").setCreationDate(fiveDaysAgo).setTechnicalDebt(twoDaysDebt);
+    Issue issue1 = new DefaultIssue().setKey("A").setCreationDate(fiveDaysAgo).setTechnicalDebt(fiveDaysDebt).setChanges(
+      newArrayList(
+        new FieldDiffs().setDiff("technicalDebt", twoDaysDebt, fiveDaysDebt).setCreatedAt(rightNow),
+        new FieldDiffs().setDiff("technicalDebt", oneDaysDebt, twoDaysDebt).setCreatedAt(fourDaysAgo),
+        new FieldDiffs().setDiff("technicalDebt", null, oneDaysDebt).setCreatedAt(nineDaysAgo)
+      )
+    );
+    Issue issue2 = new DefaultIssue().setKey("B").setCreationDate(fiveDaysAgo).setTechnicalDebt(twoDaysDebt).setChanges(
+      newArrayList(
+        new FieldDiffs().setDiff("technicalDebt", oneDaysDebt, twoDaysDebt).setCreatedAt(rightNow),
+        new FieldDiffs().setDiff("technicalDebt", null, oneDaysDebt).setCreatedAt(nineDaysAgo)
+      )
+    );
     when(issuable.issues()).thenReturn(newArrayList(issue1, issue2));
 
-    Multimap<Issue, FieldDiffs> changelogList = ArrayListMultimap.create();
-    changelogList.putAll(issue1, newArrayList(
-      new FieldDiffs().setDiff("technicalDebt", twoDaysDebt, fiveDaysDebt).setCreatedAt(rightNow),
-      new FieldDiffs().setDiff("technicalDebt", oneDaysDebt, twoDaysDebt).setCreatedAt(fourDaysAgo),
-      new FieldDiffs().setDiff("technicalDebt", null, oneDaysDebt).setCreatedAt(nineDaysAgo)
-    ));
-    changelogList.putAll(issue2, newArrayList(
-      new FieldDiffs().setDiff("technicalDebt", oneDaysDebt, twoDaysDebt).setCreatedAt(rightNow),
-      new FieldDiffs().setDiff("technicalDebt", null, oneDaysDebt).setCreatedAt(nineDaysAgo)
-    ));
-
-    when(changelogFinder.findByIssues(anyCollection())).thenReturn(changelogList);
-
     decorator.decorate(resource, context);
 
     // remember : period1 is 5daysAgo, period2 is 10daysAgo
@@ -215,9 +201,6 @@ public class NewTechnicalDebtDecoratorTest {
       (Issue) new DefaultIssue().setKey("A").setCreationDate(nineDaysAgo).setTechnicalDebt(fiveDaysDebt))
     );
 
-    Multimap<Issue, FieldDiffs> changelogList = ArrayListMultimap.create();
-    when(changelogFinder.findByIssues(anyCollection())).thenReturn(changelogList);
-
     decorator.decorate(resource, context);
 
     // remember : period1 is 5daysAgo, period2 is 10daysAgo
@@ -230,9 +213,6 @@ public class NewTechnicalDebtDecoratorTest {
       (Issue) new DefaultIssue().setKey("A").setCreationDate(nineDaysAgo).setTechnicalDebt(null))
     );
 
-    Multimap<Issue, FieldDiffs> changelogList = ArrayListMultimap.create();
-    when(changelogFinder.findByIssues(anyCollection())).thenReturn(changelogList);
-
     decorator.decorate(resource, context);
 
     // remember : period1 is 5daysAgo, period2 is 10daysAgo
@@ -247,9 +227,6 @@ public class NewTechnicalDebtDecoratorTest {
       (Issue) new DefaultIssue().setKey("A").setCreationDate(nineDaysAgo).setTechnicalDebt(fiveDaysDebt))
     );
 
-    Multimap<Issue, FieldDiffs> changelogList = ArrayListMultimap.create();
-    when(changelogFinder.findByIssues(anyCollection())).thenReturn(changelogList);
-
     decorator.decorate(resource, context);
 
     // remember : period1 is null, period2 is null
@@ -263,9 +240,6 @@ public class NewTechnicalDebtDecoratorTest {
       new DefaultIssue().setKey("B").setCreationDate(fiveDaysAgo).setTechnicalDebt(twoDaysDebt)
     ));
 
-    Multimap<Issue, FieldDiffs> changelogList = ArrayListMultimap.create();
-    when(changelogFinder.findByIssues(anyCollection())).thenReturn(changelogList);
-
     decorator.decorate(resource, context);
 
     // remember : period1 is 5daysAgo, period2 is 10daysAgo
@@ -274,25 +248,23 @@ public class NewTechnicalDebtDecoratorTest {
 
   @Test
   public void save_on_issues_with_changelog_and_issues_without_changelog() {
-    Issue issue1 = new DefaultIssue().setKey("A").setCreationDate(fiveDaysAgo).setTechnicalDebt(fiveDaysDebt);
-    Issue issue2 = new DefaultIssue().setKey("B").setCreationDate(fiveDaysAgo).setTechnicalDebt(twoDaysDebt);
+    Issue issue1 = new DefaultIssue().setKey("A").setCreationDate(fiveDaysAgo).setTechnicalDebt(fiveDaysDebt).setChanges(
+      newArrayList(
+        new FieldDiffs().setDiff("technicalDebt", twoDaysDebt, fiveDaysDebt).setCreatedAt(rightNow),
+        new FieldDiffs().setDiff("technicalDebt", oneDaysDebt, twoDaysDebt).setCreatedAt(fourDaysAgo),
+        new FieldDiffs().setDiff("technicalDebt", null, oneDaysDebt).setCreatedAt(nineDaysAgo)
+      )
+    );
+    Issue issue2 = new DefaultIssue().setKey("B").setCreationDate(fiveDaysAgo).setTechnicalDebt(twoDaysDebt).setChanges(
+      newArrayList(
+        new FieldDiffs().setDiff("technicalDebt", oneDaysDebt, twoDaysDebt).setCreatedAt(rightNow),
+        new FieldDiffs().setDiff("technicalDebt", null, oneDaysDebt).setCreatedAt(nineDaysAgo)
+      )
+    );
     Issue issue3 = new DefaultIssue().setKey("C").setCreationDate(nineDaysAgo).setTechnicalDebt(fiveDaysDebt);
     Issue issue4 = new DefaultIssue().setKey("D").setCreationDate(fiveDaysAgo).setTechnicalDebt(twoDaysDebt);
     when(issuable.issues()).thenReturn(newArrayList(issue1, issue2, issue3, issue4));
 
-    Multimap<Issue, FieldDiffs> changelogList = ArrayListMultimap.create();
-    changelogList.putAll(issue1, newArrayList(
-      new FieldDiffs().setDiff("technicalDebt", twoDaysDebt, fiveDaysDebt).setCreatedAt(rightNow),
-      new FieldDiffs().setDiff("technicalDebt", oneDaysDebt, twoDaysDebt).setCreatedAt(fourDaysAgo),
-      new FieldDiffs().setDiff("technicalDebt", null, oneDaysDebt).setCreatedAt(nineDaysAgo)
-    ));
-    changelogList.putAll(issue2, newArrayList(
-      new FieldDiffs().setDiff("technicalDebt", oneDaysDebt, twoDaysDebt).setCreatedAt(rightNow),
-      new FieldDiffs().setDiff("technicalDebt", null, oneDaysDebt).setCreatedAt(nineDaysAgo)
-    ));
-
-    when(changelogFinder.findByIssues(anyCollection())).thenReturn(changelogList);
-
     decorator.decorate(resource, context);
 
     // remember : period1 is 5daysAgo, period2 is 10daysAgo