Add ErrTxFailed. Small tweaks.

v2/command.go

@@ -19,6 +19,12 @@ type Cmder interface {
 	Err() error
 }
 
+func setCmdsErr(cmds []Cmder, e error) {
+	for _, cmd := range cmds {
+		cmd.setErr(e)
+	}
+}
+
 //------------------------------------------------------------------------------
 
 type baseCmd struct {

v2/example_test.go

@@ -108,8 +108,7 @@ func ExampleMulti() {
 
 	for {
 		cmds, err := incr(tx)
-		if err == redis.Nil {
-			// Transaction failed. Repeat.
+		if err == redis.TxFailedErr {
 			continue
 		} else if err != nil {
 			panic(err)

v2/multi.go

@@ -50,6 +50,9 @@ func (c *Multi) Discard() error {
 	return nil
 }
 
+// Exec always returns list of commands. If transaction fails
+// TxFailedErr is returned. Otherwise Exec returns error of the first
+// failed command or nil.
 func (c *Multi) Exec(f func()) ([]Cmder, error) {
 	c.cmds = []Cmder{NewStatusCmd("MULTI")}
 	f()
@@ -64,35 +67,38 @@ func (c *Multi) Exec(f func()) ([]Cmder, error) {
 
 	cn, err := c.conn()
 	if err != nil {
-		return nil, err
+		setCmdsErr(cmds[1:len(cmds)-1], err)
+		return cmds[1 : len(cmds)-1], err
 	}
 
 	// Synchronize writes and reads to the connection using mutex.
-	err = c.execCmds(cmds, cn)
+	err = c.execCmds(cn, cmds)
 	if err != nil {
-		c.removeConn(cn)
-		return nil, err
+		c.freeConn(cn, err)
+		return cmds[1 : len(cmds)-1], err
 	}
 
 	c.putConn(cn)
 	return cmds[1 : len(cmds)-1], nil
 }
 
-func (c *Multi) execCmds(cmds []Cmder, cn *conn) error {
+func (c *Multi) execCmds(cn *conn, cmds []Cmder) error {
 	err := c.writeCmd(cn, cmds...)
 	if err != nil {
+		setCmdsErr(cmds[1:len(cmds)-1], err)
 		return err
 	}
 
 	statusCmd := NewStatusCmd()
 
-	// Omit last cmduest (EXEC).
+	// Omit last command (EXEC).
 	cmdsLen := len(cmds) - 1
 
 	// Parse queued replies.
 	for i := 0; i < cmdsLen; i++ {
 		_, err = statusCmd.parseReply(cn.rd)
 		if err != nil {
+			setCmdsErr(cmds[1:len(cmds)-1], err)
 			return err
 		}
 	}
@@ -100,15 +106,21 @@ func (c *Multi) execCmds(cmds []Cmder, cn *conn) error {
 	// Parse number of replies.
 	line, err := readLine(cn.rd)
 	if err != nil {
+		setCmdsErr(cmds[1:len(cmds)-1], err)
 		return err
 	}
 	if line[0] != '*' {
-		return fmt.Errorf("redis: expected '*', but got line %q", line)
+		err := fmt.Errorf("redis: expected '*', but got line %q", line)
+		setCmdsErr(cmds[1:len(cmds)-1], err)
+		return err
 	}
 	if len(line) == 3 && line[1] == '-' && line[2] == '1' {
-		return Nil
+		setCmdsErr(cmds[1:len(cmds)-1], TxFailedErr)
+		return TxFailedErr
 	}
 
+	var firstCmdErr error
+
 	// Parse replies.
 	// Loop starts from 1 to omit first cmduest (MULTI).
 	for i := 1; i < cmdsLen; i++ {
@@ -116,10 +128,13 @@ func (c *Multi) execCmds(cmds []Cmder, cn *conn) error {
 		val, err := cmd.parseReply(cn.rd)
 		if err != nil {
 			cmd.setErr(err)
+			if firstCmdErr == nil {
+				firstCmdErr = err
+			}
 		} else {
 			cmd.setVal(val)
 		}
 	}
 
-	return nil
+	return firstCmdErr
 }

v2/parser.go

@@ -18,9 +18,12 @@ const (
 	stringFloatMap
 )
 
-// Represents Redis nil reply.
+// Redis nil reply.
 var Nil = errors.New("(nil)")
 
+// Redis transaction failed.
+var TxFailedErr = errors.New("redis: transaction failed")
+
 var (
 	errReaderTooSmall   = errors.New("redis: reader is too small")
 	errValNotSet        = errors.New("redis: value is not set")

v2/pipeline.go

@@ -35,7 +35,7 @@ func (c *Pipeline) Discard() error {
 	return nil
 }
 
-// Always returns list of commands and error of the first failed
+// Exec always returns list of commands and error of the first failed
 // command if any.
 func (c *Pipeline) Exec() ([]Cmder, error) {
 	cmds := c.cmds
@@ -47,10 +47,11 @@ func (c *Pipeline) Exec() ([]Cmder, error) {
 
 	cn, err := c.conn()
 	if err != nil {
+		setCmdsErr(cmds, err)
 		return cmds, err
 	}
 
-	if err := c.execCmds(cmds, cn); err != nil {
+	if err := c.execCmds(cn, cmds); err != nil {
 		c.freeConn(cn, err)
 		return cmds, err
 	}
@@ -59,12 +60,10 @@ func (c *Pipeline) Exec() ([]Cmder, error) {
 	return cmds, nil
 }
 
-func (c *Pipeline) execCmds(cmds []Cmder, cn *conn) error {
+func (c *Pipeline) execCmds(cn *conn, cmds []Cmder) error {
 	err := c.writeCmd(cn, cmds...)
 	if err != nil {
-		for _, cmd := range cmds {
-			cmd.setErr(err)
-		}
+		setCmdsErr(cmds, err)
 		return err
 	}
 

v2/redis.go

@@ -73,7 +73,7 @@ func (c *baseClient) init(cn *conn, password string, db int64) error {
 }
 
 func (c *baseClient) freeConn(cn *conn, err error) {
-	if err == Nil {
+	if err == Nil || err == TxFailedErr {
 		c.putConn(cn)
 	} else {
 		c.removeConn(cn)

v2/redis_test.go

@@ -2643,13 +2643,9 @@ func (t *RedisTest) transactionalIncr(c *C) ([]redis.Cmder, error) {
 	v, err := strconv.ParseInt(get.Val(), 10, 64)
 	c.Assert(err, IsNil)
 
-	cmds, err := multi.Exec(func() {
+	return multi.Exec(func() {
 		multi.Set("key", strconv.FormatInt(v+1, 10))
 	})
-	if err == redis.Nil {
-		return t.transactionalIncr(c)
-	}
-	return cmds, err
 }
 
 func (t *RedisTest) TestWatchUnwatch(c *C) {
@@ -2661,10 +2657,16 @@ func (t *RedisTest) TestWatchUnwatch(c *C) {
 	for i := 0; i < 1000; i++ {
 		wg.Add(1)
 		go func() {
-			cmds, err := t.transactionalIncr(c)
-			c.Assert(cmds, HasLen, 1)
-			c.Assert(err, IsNil)
-			c.Assert(cmds[0].Err(), IsNil)
+			for {
+				cmds, err := t.transactionalIncr(c)
+				if err == redis.TxFailedErr {
+					continue
+				}
+				c.Assert(err, IsNil)
+				c.Assert(cmds, HasLen, 1)
+				c.Assert(cmds[0].Err(), IsNil)
+				break
+			}
 			wg.Done()
 		}()
 	}