Respect interface's return type in methods

lib/Doctrine/DBAL/Cache/ArrayStatement.php

@@ -46,6 +46,8 @@ class ArrayStatement implements IteratorAggregate, ResultStatement
     public function closeCursor()
     {
         unset($this->data);
+
+        return true;
     }
 
     /**

lib/Doctrine/DBAL/Driver/IBMDB2/DB2Connection.php

@@ -8,6 +8,7 @@ use Doctrine\DBAL\ParameterType;
 use stdClass;
 use const DB2_AUTOCOMMIT_OFF;
 use const DB2_AUTOCOMMIT_ON;
+use function assert;
 use function db2_autocommit;
 use function db2_commit;
 use function db2_conn_error;
@@ -23,6 +24,7 @@ use function db2_rollback;
 use function db2_server_info;
 use function db2_stmt_errormsg;
 use function func_get_args;
+use function is_bool;
 
 class DB2Connection implements Connection, ServerInfoAwareConnection
 {
@@ -140,7 +142,10 @@ class DB2Connection implements Connection, ServerInfoAwareConnection
      */
     public function beginTransaction()
     {
-        db2_autocommit($this->conn, DB2_AUTOCOMMIT_OFF);
+        $result = db2_autocommit($this->conn, DB2_AUTOCOMMIT_OFF);
+        assert(is_bool($result));
+
+        return $result;
     }
 
     /**
@@ -151,7 +156,11 @@ class DB2Connection implements Connection, ServerInfoAwareConnection
         if (! db2_commit($this->conn)) {
             throw new DB2Exception(db2_conn_errormsg($this->conn));
         }
-        db2_autocommit($this->conn, DB2_AUTOCOMMIT_ON);
+
+        $result = db2_autocommit($this->conn, DB2_AUTOCOMMIT_ON);
+        assert(is_bool($result));
+
+        return $result;
     }
 
     /**
@@ -162,7 +171,11 @@ class DB2Connection implements Connection, ServerInfoAwareConnection
         if (! db2_rollback($this->conn)) {
             throw new DB2Exception(db2_conn_errormsg($this->conn));
         }
-        db2_autocommit($this->conn, DB2_AUTOCOMMIT_ON);
+
+        $result = db2_autocommit($this->conn, DB2_AUTOCOMMIT_ON);
+        assert(is_bool($result));
+
+        return $result;
     }
 
     /**

lib/Doctrine/DBAL/Driver/SQLAnywhere/SQLAnywhereStatement.php

@@ -313,6 +313,8 @@ class SQLAnywhereStatement implements IteratorAggregate, Statement
         $this->defaultFetchMode          = $fetchMode;
         $this->defaultFetchClass         = $arg2 ?: $this->defaultFetchClass;
         $this->defaultFetchClassCtorArgs = $arg3 ? (array) $arg3 : $this->defaultFetchClassCtorArgs;
+
+        return true;
     }
 
     /**

lib/Doctrine/DBAL/Driver/SQLSrv/SQLSrvConnection.php

@@ -152,6 +152,8 @@ class SQLSrvConnection implements Connection, ServerInfoAwareConnection
         if (! sqlsrv_begin_transaction($this->conn)) {
             throw SQLSrvException::fromSqlSrvErrors();
         }
+
+        return true;
     }
 
     /**
@@ -162,6 +164,8 @@ class SQLSrvConnection implements Connection, ServerInfoAwareConnection
         if (! sqlsrv_commit($this->conn)) {
             throw SQLSrvException::fromSqlSrvErrors();
         }
+
+        return true;
     }
 
     /**
@@ -172,6 +176,8 @@ class SQLSrvConnection implements Connection, ServerInfoAwareConnection
         if (! sqlsrv_rollback($this->conn)) {
             throw SQLSrvException::fromSqlSrvErrors();
         }
+
+        return true;
     }
 
     /**

lib/Doctrine/DBAL/Driver/SQLSrv/SQLSrvStatement.php

@@ -158,6 +158,8 @@ class SQLSrvStatement implements IteratorAggregate, Statement
 
         $this->variables[$param] = $value;
         $this->types[$param]     = $type;
+
+        return true;
     }
 
     /**
@@ -174,6 +176,8 @@ class SQLSrvStatement implements IteratorAggregate, Statement
 
         // unset the statement resource if it exists as the new one will need to be bound to the new variable
         $this->stmt = null;
+
+        return true;
     }
 
     /**
@@ -263,6 +267,8 @@ class SQLSrvStatement implements IteratorAggregate, Statement
         }
 
         $this->result = true;
+
+        return true;
     }
 
     /**