MergeOp: Record the change set

We want to record a unique identifier which can be queried later to
obtain all changes which were submitted together.

Change-Id: I5ba29aa52c5dc20b37f3b7965a026fd6e84b814b
Signed-off-by: Stefan Beller <sbeller@google.com>

gerrit-reviewdb/src/main/java/com/google/gerrit/reviewdb/client/Change.java

@@ -453,6 +453,13 @@ public final class Change {
   @Column(id = 17, notNull = false)
   protected String originalSubject;
 
+  /**
+   * Unique id for the changes submitted together assigned during merging.
+   * Only set if the status is MERGED.
+   */
+  @Column(id = 18, notNull = false)
+  protected String submissionId;
+
   protected Change() {
   }
 
@@ -479,6 +486,7 @@ public final class Change {
     currentPatchSetId = other.currentPatchSetId;
     subject = other.subject;
     originalSubject = other.originalSubject;
+    submissionId = other.submissionId;
     topic = other.topic;
   }
 
@@ -562,6 +570,14 @@ public final class Change {
     }
   }
 
+  public String getSubmissionId() {
+    return submissionId;
+  }
+
+  public void setSubmissionId(String id) {
+    this.submissionId = id;
+  }
+
   public Status getStatus() {
     return Status.forCode(status);
   }

gerrit-server/src/main/java/com/google/gerrit/server/git/MergeOp.java

@@ -27,6 +27,8 @@ import com.google.common.collect.ListMultimap;
 import com.google.common.collect.Maps;
 import com.google.common.collect.Multimap;
 import com.google.common.collect.Table;
+import com.google.common.hash.Hasher;
+import com.google.common.hash.Hashing;
 import com.google.gerrit.common.ChangeHooks;
 import com.google.gerrit.common.TimeUtil;
 import com.google.gerrit.common.data.SubmitRecord;
@@ -91,6 +93,8 @@ import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
 import java.io.IOException;
+import java.net.InetAddress;
+import java.net.UnknownHostException;
 import java.sql.Timestamp;
 import java.util.ArrayList;
 import java.util.Collection;
@@ -143,7 +147,19 @@ public class MergeOp {
 
   private final Map<Change.Id, List<SubmitRecord>> records;
   private final Map<Change.Id, CodeReviewCommit> commits;
-  private String logPrefix;
+
+  private static final String MACHINE_ID;
+  static {
+    String id;
+    try {
+      id = InetAddress.getLocalHost().getHostAddress();
+    } catch (UnknownHostException e) {
+      id = "unknown";
+    }
+    MACHINE_ID = id;
+  }
+  private String staticSubmissionId;
+  private String submissionId;
 
   private ProjectState destProject;
   private ReviewDb db;
@@ -336,10 +352,19 @@ public class MergeOp {
     }
   }
 
+  private void updateSubmissionId(Change change) {
+    Hasher h = Hashing.sha1().newHasher();
+    h.putLong(Thread.currentThread().getId())
+        .putUnencodedChars(MACHINE_ID);
+    staticSubmissionId = h.hash().toString().substring(0, 8);
+    submissionId = change.getId().get() + "-" + TimeUtil.nowMs() +
+        "-" + staticSubmissionId;
+  }
+
   public void merge(ReviewDb db, Change change, IdentifiedUser caller,
       boolean checkSubmitRules) throws NoSuchChangeException,
       OrmException, ResourceConflictException {
-    logPrefix = String.format("[%s]: ", String.valueOf(change.hashCode()));
+    updateSubmissionId(change);
     this.db = db;
     logDebug("Beginning integration of {}", change);
     try {
@@ -997,6 +1022,7 @@ public class MergeOp {
       @Override
       public Change update(Change c) {
         c.setStatus(Change.Status.MERGED);
+        c.setSubmissionId(submissionId);
         if (!merged.equals(c.currentPatchSetId())) {
           // Uncool; the patch set changed after we merged it.
           // Go back to the patch set that was actually merged.
@@ -1253,28 +1279,28 @@ public class MergeOp {
 
   private void logDebug(String msg, Object... args) {
     if (log.isDebugEnabled()) {
-      log.debug(logPrefix + msg, args);
+      log.debug("[" + submissionId + "]" + msg, args);
     }
   }
 
   private void logWarn(String msg, Throwable t) {
     if (log.isWarnEnabled()) {
-      log.warn(logPrefix + msg, t);
+      log.warn("[" + submissionId + "]" + msg, t);
     }
   }
 
   private void logWarn(String msg) {
     if (log.isWarnEnabled()) {
-      log.warn(logPrefix + msg);
+      log.warn("[" + submissionId + "]" + msg);
     }
   }
 
   private void logError(String msg, Throwable t) {
     if (log.isErrorEnabled()) {
       if (t != null) {
-        log.error(logPrefix + msg, t);
+        log.error("[" + submissionId + "]" + msg, t);
       } else {
-        log.error(logPrefix + msg);
+        log.error("[" + submissionId + "]" + msg);
       }
     }
   }

gerrit-server/src/main/java/com/google/gerrit/server/schema/SchemaVersion.java

@@ -32,7 +32,7 @@ import java.util.List;
 /** A version of the database schema. */
 public abstract class SchemaVersion {
   /** The current schema version. */
-  public static final Class<Schema_111> C = Schema_111.class;
+  public static final Class<Schema_112> C = Schema_112.class;
 
   public static int getBinaryVersion() {
     return guessVersion(C);

gerrit-server/src/main/java/com/google/gerrit/server/schema/Schema_112.java

@@ -0,0 +1,30 @@
+// Copyright (C) 2015 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.google.gerrit.server.schema;
+
+import com.google.gerrit.reviewdb.server.ReviewDb;
+import com.google.gwtorm.jdbc.JdbcSchema;
+import com.google.inject.Inject;
+import com.google.inject.Provider;
+
+import java.sql.SQLException;
+import java.sql.Statement;
+
+public class Schema_112 extends SchemaVersion {
+  @Inject
+  Schema_112(Provider<Schema_111> prior) {
+    super(prior);
+  }
+}