Fix switching CommandTag back to string

batch.go

@@ -165,19 +165,19 @@ func (b *Batch) Send(ctx context.Context, txOptions *TxOptions) error {
 // query has been sent with Exec.
 func (b *Batch) ExecResults() (pgconn.CommandTag, error) {
 	if b.err != nil {
-		return nil, b.err
+		return "", b.err
 	}
 
 	select {
 	case <-b.ctx.Done():
 		b.die(b.ctx.Err())
-		return nil, b.ctx.Err()
+		return "", b.ctx.Err()
 	default:
 	}
 
 	if err := b.ensureCommandComplete(); err != nil {
 		b.die(err)
-		return nil, err
+		return "", err
 	}
 
 	b.resultsRead++
@@ -187,7 +187,7 @@ func (b *Batch) ExecResults() (pgconn.CommandTag, error) {
 	for {
 		msg, err := b.conn.rxMsg()
 		if err != nil {
-			return nil, err
+			return "", err
 		}
 
 		switch msg := msg.(type) {
@@ -196,7 +196,7 @@ func (b *Batch) ExecResults() (pgconn.CommandTag, error) {
 			return pgconn.CommandTag(msg.CommandTag), nil
 		default:
 			if err := b.conn.processContextFreeMsg(msg); err != nil {
-				return nil, err
+				return "", err
 			}
 		}
 	}

conn.go

@@ -1184,16 +1184,16 @@ func (c *Conn) Exec(ctx context.Context, sql string, arguments ...interface{}) (
 	c.lastStmtSent = false
 	err := c.waitForPreviousCancelQuery(ctx)
 	if err != nil {
-		return nil, err
+		return "", err
 	}
 
 	if err := c.lock(); err != nil {
-		return nil, err
+		return "", err
 	}
 	defer c.unlock()
 
 	if err := c.ensureConnectionReadyForQuery(); err != nil {
-		return nil, err
+		return "", err
 	}
 
 	startTime := time.Now()
@@ -1219,18 +1219,18 @@ func (c *Conn) exec(ctx context.Context, sql string, arguments ...interface{}) (
 		c.lastStmtSent = true
 		result, err := c.pgConn.Exec(ctx, sql)
 		if err != nil {
-			return nil, err
+			return "", err
 		}
 
 		return result.CommandTag, nil
 	} else {
 		psd, err := c.pgConn.Prepare(ctx, "", sql, nil)
 		if err != nil {
-			return nil, err
+			return "", err
 		}
 
 		if len(psd.ParamOIDs) != len(arguments) {
-			return nil, errors.Errorf("expected %d arguments, got %d", len(psd.ParamOIDs), len(arguments))
+			return "", errors.Errorf("expected %d arguments, got %d", len(psd.ParamOIDs), len(arguments))
 		}
 
 		ps := &PreparedStatement{
@@ -1249,7 +1249,7 @@ func (c *Conn) exec(ctx context.Context, sql string, arguments ...interface{}) (
 
 		arguments, err = convertDriverValuers(arguments)
 		if err != nil {
-			return nil, err
+			return "", err
 		}
 
 		paramFormats := make([]int16, len(arguments))
@@ -1258,7 +1258,7 @@ func (c *Conn) exec(ctx context.Context, sql string, arguments ...interface{}) (
 			paramFormats[i] = chooseParameterFormatCode(c.ConnInfo, ps.ParameterOIDs[i], arguments[i])
 			paramValues[i], err = newencodePreparedStatementArgument(c.ConnInfo, ps.ParameterOIDs[i], arguments[i])
 			if err != nil {
-				return nil, err
+				return "", err
 			}
 
 		}
@@ -1271,7 +1271,7 @@ func (c *Conn) exec(ctx context.Context, sql string, arguments ...interface{}) (
 		c.lastStmtSent = true
 		result, err := c.pgConn.ExecPrepared(ctx, psd.Name, paramValues, paramFormats, resultFormats)
 		if err != nil {
-			return nil, err
+			return "", err
 		}
 
 		return result.CommandTag, nil

conn_pool.go

@@ -548,7 +548,7 @@ func (p *ConnPool) CopyFrom(tableName Identifier, columnNames []string, rowSrc C
 func (p *ConnPool) CopyFromReader(r io.Reader, sql string) (pgconn.CommandTag, error) {
 	c, err := p.Acquire()
 	if err != nil {
-		return nil, err
+		return "", err
 	}
 	defer p.Release(c)
 
@@ -559,7 +559,7 @@ func (p *ConnPool) CopyFromReader(r io.Reader, sql string) (pgconn.CommandTag, e
 func (p *ConnPool) CopyToWriter(w io.Writer, sql string, args ...interface{}) (pgconn.CommandTag, error) {
 	c, err := p.Acquire()
 	if err != nil {
-		return nil, err
+		return "", err
 	}
 	defer p.Release(c)
 

copy_from.go

@@ -287,11 +287,11 @@ func (c *Conn) CopyFrom(tableName Identifier, columnNames []string, rowSrc CopyF
 // CopyFromReader uses the PostgreSQL textual format of the copy protocol
 func (c *Conn) CopyFromReader(r io.Reader, sql string) (pgconn.CommandTag, error) {
 	if err := c.sendSimpleQuery(sql); err != nil {
-		return nil, err
+		return "", err
 	}
 
 	if err := c.readUntilCopyInResponse(); err != nil {
-		return nil, err
+		return "", err
 	}
 	buf := c.wbuf
 
@@ -306,7 +306,7 @@ func (c *Conn) CopyFromReader(r io.Reader, sql string) (pgconn.CommandTag, error
 		pgio.SetInt32(buf[sp:], int32(n+4))
 
 		if _, err := c.pgConn.Conn().Write(buf); err != nil {
-			return nil, err
+			return "", err
 		}
 	}
 
@@ -315,25 +315,25 @@ func (c *Conn) CopyFromReader(r io.Reader, sql string) (pgconn.CommandTag, error
 	buf = pgio.AppendInt32(buf, 4)
 
 	if _, err := c.pgConn.Conn().Write(buf); err != nil {
-		return nil, err
+		return "", err
 	}
 
 	for {
 		msg, err := c.rxMsg()
 		if err != nil {
-			return nil, err
+			return "", err
 		}
 
 		switch msg := msg.(type) {
 		case *pgproto3.ReadyForQuery:
 			c.rxReadyForQuery(msg)
-			return nil, err
+			return "", err
 		case *pgproto3.CommandComplete:
 			return pgconn.CommandTag(msg.CommandTag), nil
 		case *pgproto3.ErrorResponse:
-			return nil, c.rxErrorResponse(msg)
+			return "", c.rxErrorResponse(msg)
 		default:
-			return nil, c.processContextFreeMsg(msg)
+			return "", c.processContextFreeMsg(msg)
 		}
 	}
 }

copy_to.go

@@ -28,17 +28,17 @@ func (c *Conn) readUntilCopyOutResponse() error {
 
 func (c *Conn) CopyToWriter(w io.Writer, sql string, args ...interface{}) (pgconn.CommandTag, error) {
 	if err := c.sendSimpleQuery(sql, args...); err != nil {
-		return nil, err
+		return "", err
 	}
 
 	if err := c.readUntilCopyOutResponse(); err != nil {
-		return nil, err
+		return "", err
 	}
 
 	for {
 		msg, err := c.rxMsg()
 		if err != nil {
-			return nil, err
+			return "", err
 		}
 
 		switch msg := msg.(type) {
@@ -48,17 +48,17 @@ func (c *Conn) CopyToWriter(w io.Writer, sql string, args ...interface{}) (pgcon
 			_, err := w.Write(msg.Data)
 			if err != nil {
 				c.die(err)
-				return nil, err
+				return "", err
 			}
 		case *pgproto3.ReadyForQuery:
 			c.rxReadyForQuery(msg)
-			return nil, nil
+			return "", nil
 		case *pgproto3.CommandComplete:
 			return pgconn.CommandTag(msg.CommandTag), nil
 		case *pgproto3.ErrorResponse:
-			return nil, c.rxErrorResponse(msg)
+			return "", c.rxErrorResponse(msg)
 		default:
-			return nil, c.processContextFreeMsg(msg)
+			return "", c.processContextFreeMsg(msg)
 		}
 	}
 }

pgmock/pgmock.go

@@ -224,7 +224,7 @@ where (
 		SendMessage(&pgproto3.ParameterDescription{}),
 		SendMessage(&pgproto3.RowDescription{
 			Fields: []pgproto3.FieldDescription{
-				{Name: []byte("oid"),
+				{Name: "oid",
 					TableOID:             1247,
 					TableAttributeNumber: 65534,
 					DataTypeOID:          26,
@@ -232,7 +232,7 @@ where (
 					TypeModifier:         -1,
 					Format:               0,
 				},
-				{Name: []byte("typname"),
+				{Name: "typname",
 					TableOID:             1247,
 					TableAttributeNumber: 1,
 					DataTypeOID:          19,
@@ -435,7 +435,7 @@ where (
 		steps = append(steps, step)
 	}
 
-	steps = append(steps, SendMessage(&pgproto3.CommandComplete{CommandTag: []byte("SELECT 163")}))
+	steps = append(steps, SendMessage(&pgproto3.CommandComplete{CommandTag: "SELECT 163"}))
 	steps = append(steps, SendMessage(&pgproto3.ReadyForQuery{TxStatus: 'I'}))
 
 	steps = append(steps, []Step{
@@ -450,7 +450,7 @@ where (
 		SendMessage(&pgproto3.ParameterDescription{}),
 		SendMessage(&pgproto3.RowDescription{
 			Fields: []pgproto3.FieldDescription{
-				{Name: []byte("oid"),
+				{Name: "oid",
 					TableOID:             1247,
 					TableAttributeNumber: 65534,
 					DataTypeOID:          26,
@@ -458,7 +458,7 @@ where (
 					TypeModifier:         -1,
 					Format:               0,
 				},
-				{Name: []byte("typname"),
+				{Name: "typname",
 					TableOID:             1247,
 					TableAttributeNumber: 1,
 					DataTypeOID:          19,
@@ -475,7 +475,7 @@ where (
 		ExpectMessage(&pgproto3.Execute{}),
 		ExpectMessage(&pgproto3.Sync{}),
 		SendMessage(&pgproto3.BindComplete{}),
-		SendMessage(&pgproto3.CommandComplete{CommandTag: []byte("SELECT 0")}),
+		SendMessage(&pgproto3.CommandComplete{CommandTag: "SELECT 0"}),
 		SendMessage(&pgproto3.ReadyForQuery{TxStatus: 'I'}),
 	}...)
 
@@ -491,7 +491,7 @@ where (
 		SendMessage(&pgproto3.ParameterDescription{}),
 		SendMessage(&pgproto3.RowDescription{
 			Fields: []pgproto3.FieldDescription{
-				{Name: []byte("oid"),
+				{Name: "oid",
 					TableOID:             1247,
 					TableAttributeNumber: 65534,
 					DataTypeOID:          26,
@@ -499,7 +499,7 @@ where (
 					TypeModifier:         -1,
 					Format:               0,
 				},
-				{Name: []byte("typname"),
+				{Name: "typname",
 					TableOID:             1247,
 					TableAttributeNumber: 1,
 					DataTypeOID:          19,
@@ -507,7 +507,7 @@ where (
 					TypeModifier:         -1,
 					Format:               0,
 				},
-				{Name: []byte("typbasetype"),
+				{Name: "typbasetype",
 					TableOID:             1247,
 					TableAttributeNumber: 65534,
 					DataTypeOID:          26,
@@ -524,7 +524,7 @@ where (
 		ExpectMessage(&pgproto3.Execute{}),
 		ExpectMessage(&pgproto3.Sync{}),
 		SendMessage(&pgproto3.BindComplete{}),
-		SendMessage(&pgproto3.CommandComplete{CommandTag: []byte("SELECT 0")}),
+		SendMessage(&pgproto3.CommandComplete{CommandTag: "SELECT 0"}),
 		SendMessage(&pgproto3.ReadyForQuery{TxStatus: 'I'}),
 	}...)
 

tx.go

@@ -234,7 +234,7 @@ func (tx *Tx) CopyFrom(tableName Identifier, columnNames []string, rowSrc CopyFr
 // CopyFromReader delegates to the underlying *Conn
 func (tx *Tx) CopyFromReader(r io.Reader, sql string) (commandTag pgconn.CommandTag, err error) {
 	if tx.status != TxStatusInProgress {
-		return nil, ErrTxClosed
+		return "", ErrTxClosed
 	}
 
 	return tx.conn.CopyFromReader(r, sql)
@@ -243,7 +243,7 @@ func (tx *Tx) CopyFromReader(r io.Reader, sql string) (commandTag pgconn.Command
 // CopyToWriter delegates to the underlying *Conn
 func (tx *Tx) CopyToWriter(w io.Writer, sql string, args ...interface{}) (commandTag pgconn.CommandTag, err error) {
 	if tx.status != TxStatusInProgress {
-		return nil, ErrTxClosed
+		return "", ErrTxClosed
 	}
 
 	return tx.conn.CopyToWriter(w, sql, args...)