Non-admin users could not open a database using a mode (MODE=xxx) if the…

Non-admin users could not open a database using a mode (MODE=xxx) if the database was already open, even if the mode matched.

h2/src/main/org/h2/command/dml/Set.java

@@ -242,12 +242,14 @@ public class Set extends Prepared {
             break;
         }
         case SetTypes.MODE:
-            session.getUser().checkAdmin();
             Mode mode = Mode.getInstance(stringValue);
             if (mode == null) {
                 throw DbException.get(ErrorCode.UNKNOWN_MODE_1, stringValue);
             }
-            database.setMode(mode);
+            if (database.getMode() != mode) {
+                session.getUser().checkAdmin();
+                database.setMode(mode);
+            }
             break;
         case SetTypes.MULTI_THREADED: {
             session.getUser().checkAdmin();

h2/src/test/org/h2/test/db/TestRights.java

@@ -34,6 +34,7 @@ public class TestRights extends TestBase {
     }
 
     public void test() throws SQLException {
+        testOpenNonAdminWithMode();
         testDisallowedTables();
         testDropOwnUser();
         testGetTables();
@@ -44,6 +45,26 @@ public class TestRights extends TestBase {
         deleteDb("rights");
     }
 
+    private void testOpenNonAdminWithMode() throws SQLException {
+        deleteDb("rights");
+        Connection conn = getConnection("rights");
+        stat = conn.createStatement();
+        stat.execute("create user test password 'test'");
+        Connection conn2 = getConnection("rights", "test", getPassword("test"));
+        conn2.close();
+        conn.close();
+        // if opening alone
+        conn2 = getConnection("rights;MODE=MYSQL", "test", getPassword("test"));
+        conn2.close();
+        // if opening as the second connection
+        conn = getConnection("rights;MODE=MYSQL");
+        conn2 = getConnection("rights;MODE=MYSQL", "test", getPassword("test"));
+        conn2.close();
+        stat = conn.createStatement();
+        stat.execute("drop user test");
+        conn.close();
+    }
+
     private void testDisallowedTables() throws SQLException {
         deleteDb("rights");
         Connection conn = getConnection("rights");