bug fix

batch3.go

@@ -22,9 +22,10 @@ type (
 
 		cnt int // number of goroutines in a critical zone
 
-		res   Res
-		err   error
-		ready bool
+		res Res
+		err error
+
+		in, out bool
 	}
 
 	Batch[Res any] struct {
@@ -116,7 +117,7 @@ func (c *Controller[Res]) exit() int {
 	if c.cnt == 0 {
 		var zero Res
 		c.res, c.err = zero, nil
-		c.ready = false
+		c.in, c.out = false, false
 	}
 
 	c.mu.Unlock()
@@ -133,19 +134,22 @@ func (c *Controller[Res]) commit(ctx context.Context, err error) (Res, error) {
 again:
 	if err != nil || atomic.LoadInt32(&c.queue) == 0 {
 		c.cnt = -c.cnt
-		c.ready = true
+		c.in = true
 
 		if ep, ok := err.(PanicError); ok {
+			c.out = true
 			c.err = err
 			panic(ep.Panic)
 		} else if err != nil {
+			c.out = true
 			c.err = err
 		} else {
 			func() {
 				var res Res
 				var err error
 
 				defer func() {
+					c.out = true
 					c.res, c.err = res, err
 
 					if p := recover(); p != nil {
@@ -162,7 +166,7 @@ again:
 	} else {
 		c.cond.Wait()
 
-		if !c.ready {
+		if !c.in {
 			goto again
 		}
 	}
@@ -260,8 +264,15 @@ func (b *Batch[Res]) Rollback(ctx context.Context, err error) (Res, error) {
 	return b.c.commit(ctx, err)
 }
 
+func AsPanicError(err error) (PanicError, bool) {
+	var pe PanicError
+
+	return pe, errors.As(err, &pe)
+}
+
 func (e PanicError) Error() string {
 	return fmt.Sprintf("panic: %v", e.Panic)
 }
 
-func (noCopy) Lock() {}
+func (*noCopy) Lock()   {}
+func (*noCopy) Unlock() {}

go.mod

@@ -1,3 +1,5 @@
 module nikand.dev/go/batch
 
 go 1.18
+
+retract v0.4.0 // has a bug

multi.go

@@ -40,7 +40,10 @@ func (c *Multi[Res]) Enter(blocking bool) (b Batch[Res], coach, index int) {
 		for coach := range c.cs {
 			b, idx := c.cs[coach].Enter(false)
 			if idx >= 0 {
-				return b, coach, idx
+				return Batch[Res]{
+					c:     b.c,
+					state: b.state,
+				}, coach, idx
 			}
 		}