batchio: return Context error if cancelled with no data (#4)

zombiezen · web-flow · commit 35ce6cb7d7ad · 2020-08-25T09:02:07.000-07:00
diff --git a/batchio/batchio.go b/batchio/batchio.go
@@ -98,6 +98,9 @@ func (r *Reader) Next(ctx context.Context) ([]byte, error) {
 			return r.buf[:r.nread:r.nread], nil
 		case <-ctx.Done():
 			r.pendingRead = true
+			if r.nread == 0 {
+				return nil, ctx.Err()
+			}
 			return r.buf[:r.nread:r.nread], nil
 		}
 	}

Original file line number	Diff line number	Diff line change
`@@ -98,6 +98,9 @@ func (r *Reader) Next(ctx context.Context) ([]byte, error) {`
`98`	`98`	`return r.buf[:r.nread:r.nread], nil`
`99`	`99`	`case <-ctx.Done():`
`100`	`100`	`r.pendingRead = true`
	`101`	`+ if r.nread == 0 {`
	`102`	`+ return nil, ctx.Err()`
	`103`	`+ }`
`101`	`104`	`return r.buf[:r.nread:r.nread], nil`
`102`	`105`	`}`
`103`	`106`	`}`