Support changing Google Account identity strings

If auth.allowGoogleAccountUpgrade is set to true we now allow the
user's OpenID identity token to change during sign-in, such as if
the server hostname was recently changed.

Change-Id: I5d88ce8d39186ef22fd47b257a3c791c2b2c12bd
Signed-off-by: Shawn O. Pearce <sop@google.com>

Documentation/config-gerrit.txt

@@ -131,24 +131,18 @@ By default this is false (no agreements are used).
 
 auth.allowGoogleAccountUpgrade::
 +
-Allow old Gerrit1 users to seamlessly upgrade from Google Accounts
-on Google App Engine to OpenID authentication.  This should only be
-set to true on a Gerrit2 database that was imported from a Gerrit1
-database run on Google App Engine.  Having it enabled incurs an
-extra database query when new Google Account users register with
-the Gerrit2 server.
+Allows Google Account users to automatically update their Gerrit
+account when/if their Google Account OpenID identity token changes.
+Identity tokens can change if the server changes hostnames, or
+for other reasons known only to Google.  The upgrade path works
+by matching users by email address if the identity is not present,
+and then changing the identity.
 +
-Its strongly encouraged to unset this once the following query
-drops to 0, or close to 0:
+This setting also permits old Gerrit 1.x users to seamlessly upgrade
+from Google Accounts on Google App Engine to OpenID authentication.
 +
-====
-  SELECT COUNT(*) FROM account_external_ids e
-  WHERE e.external_id LIKE 'Google Account %'
-  AND NOT EXISTS (SELECT 1
-    FROM account_external_ids o
-    WHERE o.account_id = e.account_id
-	AND o.external_id LIKE '%.google.com%/id?id=%');
-====
+Having this enabled incurs an extra database query when Google
+Account users register with the Gerrit2 server.
 +
 By default, unset/false.
 

src/main/java/com/google/gerrit/server/account/AccountManager.java

@@ -25,6 +25,7 @@ import com.google.gwtorm.client.Transaction;
 import com.google.inject.Inject;
 import com.google.inject.Singleton;
 
+import java.util.ArrayList;
 import java.util.Collections;
 import java.util.List;
 
@@ -175,16 +176,57 @@ public class AccountManager {
     if (authConfig.isAllowGoogleAccountUpgrade()
         && who.isScheme(OpenIdUtil.URL_GOOGLE + "?")
         && who.getEmailAddress() != null) {
-      final List<AccountExternalId> legacyAppEngine =
-          db.accountExternalIds().byExternal(
-              AccountExternalId.LEGACY_GAE + who.getEmailAddress()).toList();
+      final List<AccountExternalId> openId = new ArrayList<AccountExternalId>();
+      final List<AccountExternalId> v1 = new ArrayList<AccountExternalId>();
 
-      if (legacyAppEngine.size() == 1) {
+      for (final AccountExternalId extId : db.accountExternalIds()
+          .byEmailAddress(who.getEmailAddress())) {
+        if (extId.isScheme(OpenIdUtil.URL_GOOGLE + "?")) {
+          openId.add(extId);
+        } else if (extId.isScheme(AccountExternalId.LEGACY_GAE)) {
+          v1.add(extId);
+        }
+      }
+
+      if (!openId.isEmpty()) {
+        // The user has already registered with an OpenID from Google, but
+        // Google may have changed the user's OpenID identity if this server
+        // name has changed. Insert a new identity for the user.
+        //
+        final Account.Id accountId = openId.get(0).getAccountId();
+
+        if (openId.size() > 1) {
+          // Validate all matching identities are actually the same user.
+          //
+          for (final AccountExternalId extId : openId) {
+            if (!accountId.equals(extId.getAccountId())) {
+              throw new AccountException("Multiple user accounts for "
+                  + who.getEmailAddress() + " using Google Accounts provider");
+            }
+          }
+        }
+
+        final AccountExternalId newId = createId(accountId, who);
+        newId.setEmailAddress(who.getEmailAddress());
+        newId.setLastUsedOn();
+
+        if (openId.size() == 1) {
+          final AccountExternalId oldId = openId.get(0);
+          final Transaction txn = db.beginTransaction();
+          db.accountExternalIds().delete(Collections.singleton(oldId), txn);
+          db.accountExternalIds().insert(Collections.singleton(newId), txn);
+          txn.commit();
+        } else {
+          db.accountExternalIds().insert(Collections.singleton(newId));
+        }
+        return new AuthResult(accountId, false);
+
+      } else if (v1.size() == 1) {
         // Exactly one user was imported from Gerrit 1.x with this email
         // address. Upgrade their account by deleting the legacy import
         // identity and creating a new identity matching the token we have.
         //
-        final AccountExternalId oldId = legacyAppEngine.get(0);
+        final AccountExternalId oldId = v1.get(0);
         final AccountExternalId newId = createId(oldId.getAccountId(), who);
         newId.setEmailAddress(who.getEmailAddress());
         newId.setLastUsedOn();
@@ -194,7 +236,7 @@ public class AccountManager {
         txn.commit();
         return new AuthResult(newId.getAccountId(), false);
 
-      } else if (legacyAppEngine.size() > 1) {
+      } else if (v1.size() > 1) {
         throw new AccountException("Multiple Gerrit 1.x accounts found");
       }
     }