Let users know which commit prevents submit in case of MISSING_DEPENDENCY

If a change cannot be submitted because it depends on a commit that
cannot be merged the user got the following message:

  Depends on change that was not submitted.

This message is not very helpful since it doesn't contain which commit
prevents the submit.

Now we return:

  Depends on change that was not submitted. Commit <commit> depends on
  commit <other-commit> which cannot be merged.

Change-Id: I92db5a74dea6e88bd01b0df21a394ddf21f977b5
Signed-off-by: Edwin Kempin <ekempin@google.com>

java/com/google/gerrit/server/git/CodeReviewCommit.java

@@ -17,11 +17,13 @@ package com.google.gerrit.server.git;
 import static com.google.common.base.Preconditions.checkArgument;
 
 import com.google.common.collect.Ordering;
+import com.google.gerrit.common.Nullable;
 import com.google.gerrit.reviewdb.client.Change;
 import com.google.gerrit.reviewdb.client.PatchSet;
 import com.google.gerrit.server.notedb.ChangeNotes;
 import com.google.gerrit.server.submit.CommitMergeStatus;
 import java.io.IOException;
+import java.util.Optional;
 import org.eclipse.jgit.errors.IncorrectObjectTypeException;
 import org.eclipse.jgit.errors.MissingObjectException;
 import org.eclipse.jgit.lib.AnyObjectId;
@@ -118,6 +120,12 @@ public class CodeReviewCommit extends RevCommit {
    */
   private CommitMergeStatus statusCode;
 
+  /**
+   * Message for the status that is returned to the calling user if the status indicates a problem
+   * that prevents submit.
+   */
+  private Optional<String> statusMessage = Optional.empty();
+
   public CodeReviewCommit(AnyObjectId id) {
     super(id);
   }
@@ -134,6 +142,14 @@ public class CodeReviewCommit extends RevCommit {
     this.statusCode = statusCode;
   }
 
+  public Optional<String> getStatusMessage() {
+    return statusMessage;
+  }
+
+  public void setStatusMessage(@Nullable String statusMessage) {
+    this.statusMessage = Optional.ofNullable(statusMessage);
+  }
+
   public PatchSet.Id getPatchsetId() {
     return patchsetId;
   }

java/com/google/gerrit/server/submit/CommitMergeStatus.java

@@ -67,13 +67,13 @@ public enum CommitMergeStatus {
           + "\n"
           + "Project policy requires all commits to contain modifications to at least one file.");
 
-  private final String message;
+  private final String description;
 
-  CommitMergeStatus(String message) {
+  CommitMergeStatus(String description) {
-    this.message = message;
+    this.description = description;
   }
 
-  public String getMessage() {
+  public String getDescription() {
-    return message;
+    return description;
   }
 }

java/com/google/gerrit/server/submit/MergeSorter.java

@@ -14,7 +14,6 @@
 
 package com.google.gerrit.server.submit;
 
-import com.google.common.flogger.FluentLogger;
 import com.google.gerrit.server.git.CodeReviewCommit;
 import com.google.gerrit.server.git.CodeReviewCommit.CodeReviewRevWalk;
 import java.io.IOException;
@@ -27,8 +26,6 @@ import org.eclipse.jgit.revwalk.RevCommitList;
 import org.eclipse.jgit.revwalk.RevFlag;
 
 public class MergeSorter {
-  private static final FluentLogger logger = FluentLogger.forEnclosingClass();
-
   private final CodeReviewRevWalk rw;
   private final RevFlag canMergeFlag;
   private final Set<RevCommit> accepted;
@@ -65,9 +62,10 @@ public class MergeSorter {
           // We cannot merge n as it would bring something we
           // aren't permitted to merge at this time. Drop n.
           //
-          logger.atFine().log(
-              "commit %s depends on commit %s which cannot be merged", n.name(), c.name());
           n.setStatusCode(CommitMergeStatus.MISSING_DEPENDENCY);
+          n.setStatusMessage(
+              String.format(
+                  "Commit %s depends on commit %s which cannot be merged.", n.name(), c.name()));
           break;
         }
         contents.add(c);

java/com/google/gerrit/server/submit/RebaseSorter.java

@@ -81,9 +81,10 @@ public class RebaseSorter {
             // We cannot merge n as it would bring something we
             // aren't permitted to merge at this time. Drop n.
             //
-            logger.atFine().log(
-                "commit %s depends on commit %s which cannot be merged", n.name(), c.name());
             n.setStatusCode(CommitMergeStatus.MISSING_DEPENDENCY);
+            n.setStatusMessage(
+                String.format(
+                    "Commit %s depends on commit %s which cannot be merged.", n.name(), c.name()));
           }
           // Stop RevWalk because c is either a merged commit or a missing
           // dependency. Not need to walk further.

java/com/google/gerrit/server/submit/SubmitStrategyListener.java

@@ -113,7 +113,13 @@ public class SubmitStrategyListener implements BatchUpdateListener {
         commitStatus.problem(id, "internal error: change not processed by merge strategy");
         continue;
       }
-      logger.atFine().log("change %d: status for commit %s is %s", id.get(), commit.name(), s);
+      if (commit.getStatusMessage().isPresent()) {
+        logger.atFine().log(
+            "change %d: Status for commit %s is %s. %s",
+            id.get(), commit.name(), s, commit.getStatusMessage().get());
+      } else {
+        logger.atFine().log("change %d: Status for commit %s is %s.", id.get(), commit.name(), s);
+      }
       switch (s) {
         case CLEAN_MERGE:
         case CLEAN_REBASE:
@@ -136,7 +142,11 @@ public class SubmitStrategyListener implements BatchUpdateListener {
         case MISSING_DEPENDENCY:
           // TODO(dborowitz): Reformat these messages to be more appropriate for
           // short problem descriptions.
-          commitStatus.problem(id, CharMatcher.is('\n').collapseFrom(s.getMessage(), ' '));
+          String message = s.getDescription();
+          if (commit.getStatusMessage().isPresent()) {
+            message += " " + commit.getStatusMessage().get();
+          }
+          commitStatus.problem(id, CharMatcher.is('\n').collapseFrom(message, ' '));
           break;
 
         default:

java/com/google/gerrit/server/submit/SubmitStrategyOp.java

@@ -438,7 +438,7 @@ abstract class SubmitStrategyOp implements BatchUpdateOp {
   private ChangeMessage message(ChangeContext ctx, CodeReviewCommit commit, CommitMergeStatus s)
       throws OrmException {
     checkNotNull(s, "CommitMergeStatus may not be null");
-    String txt = s.getMessage();
+    String txt = s.getDescription();
     if (s == CommitMergeStatus.CLEAN_MERGE) {
       return message(ctx, commit.getPatchsetId(), txt + getByAccountName());
     } else if (s == CommitMergeStatus.CLEAN_REBASE || s == CommitMergeStatus.CLEAN_PICK) {

javatests/com/google/gerrit/acceptance/rest/change/SubmitByCherryPickIT.java

@@ -380,7 +380,7 @@ public class SubmitByCherryPickIT extends AbstractSubmit {
     ChangeInfo info2 = get(change2.getChangeId(), MESSAGES);
     assertThat(info2.status).isEqualTo(ChangeStatus.MERGED);
     assertThat(Iterables.getLast(info2.messages).message)
-        .isEqualTo(CommitMergeStatus.SKIPPED_IDENTICAL_TREE.getMessage());
+        .isEqualTo(CommitMergeStatus.SKIPPED_IDENTICAL_TREE.getDescription());
 
     assertRefUpdatedEvents(initialHead, headAfterFirstSubmit);
     assertChangeMergedEvents(

javatests/com/google/gerrit/acceptance/rest/change/SubmitByMergeIfNecessaryIT.java

@@ -403,7 +403,12 @@ public class SubmitByMergeIfNecessaryIT extends AbstractSubmitByMerge {
             + "Change "
             + change3a.getChange().getId()
             + ": Depends on change that"
-            + " was not submitted.");
+            + " was not submitted."
+            + " Commit "
+            + change3a.getCommit().name()
+            + " depends on commit "
+            + change2.getCommit().name()
+            + " which cannot be merged.");
 
     RevCommit tipbranch = getRemoteLog(project, "branch").get(0);
     assertThat(tipbranch.getShortMessage()).isEqualTo(change1.getCommit().getShortMessage());
@@ -501,7 +506,12 @@ public class SubmitByMergeIfNecessaryIT extends AbstractSubmitByMerge {
         "Failed to submit 1 change due to the following problems:\n"
             + "Change "
             + change3.getPatchSetId().getParentKey().get()
-            + ": Depends on change that was not submitted.");
+            + ": Depends on change that was not submitted."
+            + " Commit "
+            + change3.getCommit().name()
+            + " depends on commit "
+            + change2result.getCommit().name()
+            + " which cannot be merged.");
 
     assertRefUpdatedEvents();
     assertChangeMergedEvents();