Tx.Status handles in transaction error

refs #421

tx.go

@@ -39,6 +39,7 @@ const (
 	TxStatusInProgress      = 0
 	TxStatusCommitFailure   = -1
 	TxStatusRollbackFailure = -2
+	TxStatusInFailure       = -3
 	TxStatusCommitSuccess   = 1
 	TxStatusRollbackSuccess = 2
 )
@@ -70,6 +71,7 @@ func (txOptions *TxOptions) beginSQL() string {
 }
 
 var ErrTxClosed = errors.New("tx is closed")
+var ErrTxInFailure = errors.New("tx failed")
 
 // ErrTxCommitRollback occurs when an error has occurred in a transaction and
 // Commit() is called. PostgreSQL accepts COMMIT on aborted transactions, but
@@ -115,7 +117,7 @@ func (tx *Tx) Commit() error {
 
 // CommitEx commits the transaction with a context.
 func (tx *Tx) CommitEx(ctx context.Context) error {
-	if tx.status != TxStatusInProgress {
+	if !(tx.status == TxStatusInProgress || tx.status == TxStatusInFailure) {
 		return ErrTxClosed
 	}
 
@@ -150,7 +152,7 @@ func (tx *Tx) Rollback() error {
 
 // RollbackEx is the context version of Rollback
 func (tx *Tx) RollbackEx(ctx context.Context) error {
-	if tx.status != TxStatusInProgress {
+	if !(tx.status == TxStatusInProgress || tx.status == TxStatusInFailure) {
 		return ErrTxClosed
 	}
 
@@ -177,6 +179,9 @@ func (tx *Tx) Exec(sql string, arguments ...interface{}) (commandTag CommandTag,
 
 // ExecEx delegates to the underlying *Conn
 func (tx *Tx) ExecEx(ctx context.Context, sql string, options *QueryExOptions, arguments ...interface{}) (commandTag CommandTag, err error) {
+	if tx.status == TxStatusInFailure {
+		return CommandTag(""), ErrTxInFailure
+	}
 	if tx.status != TxStatusInProgress {
 		return CommandTag(""), ErrTxClosed
 	}
@@ -191,6 +196,9 @@ func (tx *Tx) Prepare(name, sql string) (*PreparedStatement, error) {
 
 // PrepareEx delegates to the underlying *Conn
 func (tx *Tx) PrepareEx(ctx context.Context, name, sql string, opts *PrepareExOptions) (*PreparedStatement, error) {
+	if tx.status == TxStatusInFailure {
+		return nil, ErrTxInFailure
+	}
 	if tx.status != TxStatusInProgress {
 		return nil, ErrTxClosed
 	}
@@ -205,6 +213,11 @@ func (tx *Tx) Query(sql string, args ...interface{}) (*Rows, error) {
 
 // QueryEx delegates to the underlying *Conn
 func (tx *Tx) QueryEx(ctx context.Context, sql string, options *QueryExOptions, args ...interface{}) (*Rows, error) {
+	if tx.status == TxStatusInFailure {
+		// Because checking for errors can be deferred to the *Rows, build one with the error
+		err := ErrTxInFailure
+		return &Rows{closed: true, err: err}, err
+	}
 	if tx.status != TxStatusInProgress {
 		// Because checking for errors can be deferred to the *Rows, build one with the error
 		err := ErrTxClosed
@@ -238,6 +251,9 @@ func (tx *Tx) CopyFrom(tableName Identifier, columnNames []string, rowSrc CopyFr
 // Status returns the status of the transaction from the set of
 // pgx.TxStatus* constants.
 func (tx *Tx) Status() int8 {
+	if tx.status == TxStatusInProgress && tx.conn.txStatus == 'E' {
+		tx.status = TxStatusInFailure
+	}
 	return tx.status
 }