Merge "Add option to skip diff computations when requesting change details."

Documentation/rest-api-changes.txt

@@ -318,6 +318,11 @@ effect.
 A change's mergeability can be requested separately by calling the
 link:#get-mergeable[get-mergeable] endpoint.
 --
+[[skip_diffstat]]
+--
+* `SKIP_DIFFSTAT`: skip the 'insertions' and 'deletions' field in link:#change-info[ChangeInfo].
+ For large trees, their computation may be expensive.
+--
 
 [[submittable]]
 --

java/com/google/gerrit/extensions/api/changes/ChangeApi.java

@@ -248,12 +248,16 @@ public interface ChangeApi {
    * <ul>
    *   <li>{@code CHECK} is omitted, to skip consistency checks.
    *   <li>{@code SKIP_MERGEABLE} is omitted, so the {@code mergeable} bit <em>is</em> set.
+   *   <li>{@code SKIP_DIFFSTAT} is omitted to ensure diffstat calculations.
    * </ul>
    */
   default ChangeInfo get() throws RestApiException {
     return get(
         EnumSet.complementOf(
-            EnumSet.of(ListChangesOption.CHECK, ListChangesOption.SKIP_MERGEABLE)));
+            EnumSet.of(
+                ListChangesOption.CHECK,
+                ListChangesOption.SKIP_MERGEABLE,
+                ListChangesOption.SKIP_DIFFSTAT)));
   }
 
   /** {@link #get(ListChangesOption...)} with no options included. */

java/com/google/gerrit/extensions/client/ListChangesOption.java

@@ -75,7 +75,13 @@ public enum ListChangesOption implements ListOption {
   TRACKING_IDS(21),
 
   /** Skip mergeability data */
-  SKIP_MERGEABLE(22);
+  SKIP_MERGEABLE(22),
+
+  /**
+   * Skip diffstat computation that compute the insertions field (number of lines inserted) and
+   * deletions field (number of lines deleted)
+   */
+  SKIP_DIFFSTAT(23);
 
   private final int value;
 

java/com/google/gerrit/server/change/ChangeJson.java

@@ -28,6 +28,7 @@ import static com.google.gerrit.extensions.client.ListChangesOption.LABELS;
 import static com.google.gerrit.extensions.client.ListChangesOption.MESSAGES;
 import static com.google.gerrit.extensions.client.ListChangesOption.REVIEWED;
 import static com.google.gerrit.extensions.client.ListChangesOption.REVIEWER_UPDATES;
+import static com.google.gerrit.extensions.client.ListChangesOption.SKIP_DIFFSTAT;
 import static com.google.gerrit.extensions.client.ListChangesOption.SKIP_MERGEABLE;
 import static com.google.gerrit.extensions.client.ListChangesOption.SUBMITTABLE;
 import static com.google.gerrit.extensions.client.ListChangesOption.TRACKING_IDS;
@@ -516,10 +517,12 @@ public class ChangeJson {
         out.submittable = submittable(cd);
       }
     }
-    Optional<ChangedLines> changedLines = cd.changedLines();
+    if (!has(SKIP_DIFFSTAT)) {
-    if (changedLines.isPresent()) {
+      Optional<ChangedLines> changedLines = cd.changedLines();
-      out.insertions = changedLines.get().insertions;
+      if (changedLines.isPresent()) {
-      out.deletions = changedLines.get().deletions;
+        out.insertions = changedLines.get().insertions;
+        out.deletions = changedLines.get().deletions;
+      }
     }
     out.isPrivate = in.isPrivate() ? true : null;
     out.workInProgress = in.isWorkInProgress() ? true : null;

javatests/com/google/gerrit/acceptance/api/change/ChangeIT.java

@@ -55,12 +55,16 @@ import static com.google.gerrit.server.group.SystemGroupBackend.REGISTERED_USERS
 import static com.google.gerrit.server.project.testing.TestLabels.label;
 import static com.google.gerrit.server.project.testing.TestLabels.value;
 import static com.google.gerrit.testing.GerritJUnit.assertThrows;
+import static com.google.gerrit.truth.CacheStatsSubject.assertThat;
+import static com.google.gerrit.truth.CacheStatsSubject.cloneStats;
 import static java.nio.charset.StandardCharsets.UTF_8;
 import static java.util.concurrent.TimeUnit.SECONDS;
 import static java.util.stream.Collectors.joining;
 import static java.util.stream.Collectors.toList;
 import static java.util.stream.Collectors.toSet;
 
+import com.google.common.cache.Cache;
+import com.google.common.cache.CacheStats;
 import com.google.common.collect.ImmutableList;
 import com.google.common.collect.ImmutableMap;
 import com.google.common.collect.ImmutableSet;
@@ -156,6 +160,12 @@ import com.google.gerrit.server.group.SystemGroupBackend;
 import com.google.gerrit.server.index.change.ChangeIndex;
 import com.google.gerrit.server.index.change.ChangeIndexCollection;
 import com.google.gerrit.server.index.change.IndexedChangeQuery;
+import com.google.gerrit.server.patch.DiffSummary;
+import com.google.gerrit.server.patch.DiffSummaryKey;
+import com.google.gerrit.server.patch.IntraLineDiff;
+import com.google.gerrit.server.patch.IntraLineDiffKey;
+import com.google.gerrit.server.patch.PatchList;
+import com.google.gerrit.server.patch.PatchListKey;
 import com.google.gerrit.server.project.testing.TestLabels;
 import com.google.gerrit.server.query.change.ChangeData;
 import com.google.gerrit.server.query.change.ChangeQueryBuilder.ChangeOperatorFactory;
@@ -168,6 +178,7 @@ import com.google.gerrit.testing.FakeEmailSender.Message;
 import com.google.gerrit.testing.TestTimeUtil;
 import com.google.inject.AbstractModule;
 import com.google.inject.Inject;
+import com.google.inject.name.Named;
 import java.io.IOException;
 import java.sql.Timestamp;
 import java.util.ArrayList;
@@ -207,6 +218,18 @@ public class ChangeIT extends AbstractDaemonTest {
   @Inject private ProjectOperations projectOperations;
   @Inject private RequestScopeOperations requestScopeOperations;
 
+  @Inject
+  @Named("diff")
+  private Cache<PatchListKey, PatchList> fileCache;
+
+  @Inject
+  @Named("diff_intraline")
+  private Cache<IntraLineDiffKey, IntraLineDiff> intraCache;
+
+  @Inject
+  @Named("diff_summary")
+  private Cache<DiffSummaryKey, DiffSummary> diffSummaryCache;
+
   private ChangeIndexedCounter changeIndexedCounter;
   private RegistrationHandle changeIndexedCounterHandle;
 
@@ -257,6 +280,48 @@ public class ChangeIT extends AbstractDaemonTest {
     assertThat(c.owner.avatars).isNull();
   }
 
+  @Test
+  public void diffStatShouldComputeInsertionsAndDeletions() throws Exception {
+    String fileName = "a_new_file.txt";
+    String fileContent = "First line\nSecond line\n";
+    PushOneCommit.Result result = createChange("Add a file", fileName, fileContent);
+    String triplet = project.get() + "~master~" + result.getChangeId();
+    ChangeInfo change = gApi.changes().id(triplet).get();
+    assertThat(change.insertions).isNotNull();
+    assertThat(change.deletions).isNotNull();
+  }
+
+  @Test
+  public void diffStatShouldSkipInsertionsAndDeletions() throws Exception {
+    String fileName = "a_new_file.txt";
+    String fileContent = "First line\nSecond line\n";
+    PushOneCommit.Result result = createChange("Add a file", fileName, fileContent);
+    String triplet = project.get() + "~master~" + result.getChangeId();
+    ChangeInfo change =
+        gApi.changes().id(triplet).get(ImmutableList.of(ListChangesOption.SKIP_DIFFSTAT));
+    assertThat(change.insertions).isNull();
+    assertThat(change.deletions).isNull();
+  }
+
+  @Test
+  public void skipDiffstatOptionAvoidsAllDiffComputations() throws Exception {
+    String fileName = "a_new_file.txt";
+    String fileContent = "First line\nSecond line\n";
+    PushOneCommit.Result result = createChange("Add a file", fileName, fileContent);
+    String triplet = project.get() + "~master~" + result.getChangeId();
+    CacheStats startPatch = cloneStats(fileCache.stats());
+    CacheStats startIntra = cloneStats(intraCache.stats());
+    CacheStats startSummary = cloneStats(diffSummaryCache.stats());
+    gApi.changes().id(triplet).get(ImmutableList.of(ListChangesOption.SKIP_DIFFSTAT));
+
+    assertThat(fileCache.stats()).since(startPatch).hasMissCount(0);
+    assertThat(fileCache.stats()).since(startPatch).hasHitCount(0);
+    assertThat(intraCache.stats()).since(startIntra).hasMissCount(0);
+    assertThat(intraCache.stats()).since(startIntra).hasHitCount(0);
+    assertThat(diffSummaryCache.stats()).since(startSummary).hasMissCount(0);
+    assertThat(diffSummaryCache.stats()).since(startSummary).hasHitCount(0);
+  }
+
   @Test
   public void skipMergeable() throws Exception {
     PushOneCommit.Result r = createChange();