Create a user branch for every account

Make sure that for every account a user branch exists that has an
initial empty commit with the registration date as commit time. The
commit timestamp of the first commit on a user branch will be used as
registration timestamp when accounts are stored in NoteDb.

When an account is created create the user branch with an initial
empty commit that has the registration date as commit time.

For existing accounts add a schema migration that:

- creates the user branch with an initial empty commit that has the
  registration date as commit time if the user branch doesn't exist yet
- rewrites the user branch if it already exists and inserts an initial
  empty commit with the registration date as commit time (if such a
  commit doesn't exist yet).

Change-Id: I81491a253350a43f094fdfcb32298efde0cb086a
Signed-off-by: Edwin Kempin <ekempin@google.com>

gerrit-acceptance-tests/src/test/java/com/google/gerrit/acceptance/api/accounts/AccountIT.java

@@ -51,7 +51,6 @@ import com.google.gerrit.extensions.api.accounts.EmailInput;
 import com.google.gerrit.extensions.api.changes.AddReviewerInput;
 import com.google.gerrit.extensions.api.changes.ReviewInput;
 import com.google.gerrit.extensions.api.changes.StarsInput;
-import com.google.gerrit.extensions.client.GeneralPreferencesInfo;
 import com.google.gerrit.extensions.common.AccountInfo;
 import com.google.gerrit.extensions.common.ChangeInfo;
 import com.google.gerrit.extensions.common.GpgKeyInfo;
@@ -74,6 +73,7 @@ import com.google.gerrit.server.account.externalids.ExternalIds;
 import com.google.gerrit.server.account.externalids.ExternalIdsUpdate;
 import com.google.gerrit.server.config.AllUsersName;
 import com.google.gerrit.server.git.ProjectConfig;
+import com.google.gerrit.server.notedb.rebuild.ChangeRebuilderImpl;
 import com.google.gerrit.server.project.RefPattern;
 import com.google.gerrit.server.util.MagicBranch;
 import com.google.gerrit.testutil.ConfigSuite;
@@ -100,6 +100,8 @@ import org.eclipse.jgit.lib.Config;
 import org.eclipse.jgit.lib.Ref;
 import org.eclipse.jgit.lib.RefUpdate;
 import org.eclipse.jgit.lib.Repository;
+import org.eclipse.jgit.revwalk.RevCommit;
+import org.eclipse.jgit.revwalk.RevWalk;
 import org.eclipse.jgit.transport.PushCertificateIdent;
 import org.eclipse.jgit.transport.PushResult;
 import org.eclipse.jgit.transport.RemoteRefUpdate;
@@ -183,6 +185,26 @@ public class AccountIT extends AbstractDaemonTest {
     }
   }
 
+  @Test
+  public void create() throws Exception {
+    TestAccount foo = accounts.create("foo");
+    AccountInfo info = gApi.accounts().id(foo.id.get()).get();
+    assertThat(info.username).isEqualTo("foo");
+
+    // check user branch
+    try (Repository repo = repoManager.openRepository(allUsers);
+        RevWalk rw = new RevWalk(repo)) {
+      Ref ref = repo.exactRef(RefNames.refsUsers(foo.getId()));
+      assertThat(ref).isNotNull();
+      RevCommit c = rw.parseCommit(ref.getObjectId());
+      long timestampDiffMs =
+          Math.abs(
+              c.getCommitTime() * 1000L
+                  - accountCache.get(foo.getId()).getAccount().getRegisteredOn().getTime());
+      assertThat(timestampDiffMs).isAtMost(ChangeRebuilderImpl.MAX_WINDOW_MS);
+    }
+  }
+
   @Test
   public void get() throws Exception {
     AccountInfo info = gApi.accounts().id("admin").get();
@@ -553,7 +575,7 @@ public class AccountIT extends AbstractDaemonTest {
   @Test
   @Sandboxed
   public void fetchUserBranch() throws Exception {
-    ensureUserBranchCreated(user);
+    setApiUser(user);
 
     TestRepository<InMemoryRepository> allUsersRepo = cloneProject(allUsers, user);
     String userRefName = RefNames.refsUsers(user.id);
@@ -603,8 +625,6 @@ public class AccountIT extends AbstractDaemonTest {
 
   @Test
   public void pushToUserBranch() throws Exception {
-    ensureUserBranchCreated(admin);
-
     TestRepository<InMemoryRepository> allUsersRepo = cloneProject(allUsers);
     fetch(allUsersRepo, RefNames.refsUsers(admin.id) + ":userRef");
     allUsersRepo.reset("userRef");
@@ -617,8 +637,6 @@ public class AccountIT extends AbstractDaemonTest {
 
   @Test
   public void pushToUserBranchForReview() throws Exception {
-    ensureUserBranchCreated(admin);
-
     String userRefName = RefNames.refsUsers(admin.id);
     TestRepository<InMemoryRepository> allUsersRepo = cloneProject(allUsers);
     fetch(allUsersRepo, userRefName + ":userRef");
@@ -640,8 +658,6 @@ public class AccountIT extends AbstractDaemonTest {
 
   @Test
   public void pushWatchConfigToUserBranch() throws Exception {
-    ensureUserBranchCreated(admin);
-
     TestRepository<InMemoryRepository> allUsersRepo = cloneProject(allUsers);
     fetch(allUsersRepo, RefNames.refsUsers(admin.id) + ":userRef");
     allUsersRepo.reset("userRef");
@@ -683,8 +699,6 @@ public class AccountIT extends AbstractDaemonTest {
   @Test
   @Sandboxed
   public void cannotDeleteUserBranch() throws Exception {
-    ensureUserBranchCreated(admin);
-
     grant(
         Permission.DELETE,
         allUsers,
@@ -707,8 +721,6 @@ public class AccountIT extends AbstractDaemonTest {
   @Test
   @Sandboxed
   public void deleteUserBranchWithAccessDatabaseCapability() throws Exception {
-    ensureUserBranchCreated(admin);
-
     allowGlobalCapabilities(REGISTERED_USERS, GlobalCapability.ACCESS_DATABASE);
     grant(
         Permission.DELETE,
@@ -1019,12 +1031,4 @@ public class AccountIT extends AbstractDaemonTest {
     assertThat(accounts).hasSize(1);
     assertThat(Iterables.getOnlyElement(accounts)).isEqualTo(expectedAccount.getId());
   }
-
-  private void ensureUserBranchCreated(TestAccount account) throws Exception {
-    // Change something in the user preferences to ensure that the user branch is created.
-    setApiUser(account);
-    GeneralPreferencesInfo input = new GeneralPreferencesInfo();
-    input.changesPerPage = GeneralPreferencesInfo.defaults().changesPerPage + 10;
-    gApi.accounts().self().setPreferences(input);
-  }
 }