From 9fb7b185fcde9b49fa0524b6001127612874f1a4 Mon Sep 17 00:00:00 2001
From: Koala Yeung <koalay@gmail.com>
Date: Thu, 18 Feb 2021 13:58:13 +0800
Subject: [PATCH 1/2] client: properly close down internal idpool on Close

* Client.Close() now also close the internal idPool implementation,
  which effectively close the channel in it.
---
 client.go | 31 +++++++++++++++++++++++++++++--
 1 file changed, 29 insertions(+), 2 deletions(-)

diff --git a/client.go b/client.go
index 6e9dc66..89bda2c 100644
--- a/client.go
+++ b/client.go
@@ -18,6 +18,7 @@ import (
 	"io"
 	"net"
 	"net/http"
+	"runtime"
 	"strconv"
 	"strings"
 	"sync"
@@ -68,19 +69,26 @@ type idPool struct {
 }
 
 // AllocID implements Client.AllocID
-func (p *idPool) Alloc() uint16 {
+func (p *idPool) Alloc() (id uint16) {
 	return <-p.IDs
 }
 
 // ReleaseID implements Client.ReleaseID
 func (p *idPool) Release(id uint16) {
 	go func() {
+		defer recoverSendOnClosedChannel()
+
 		// release the ID back to channel for reuse
 		// use goroutine to prev0, ent blocking ReleaseID
 		p.IDs <- id
 	}()
 }
 
+func (p *idPool) Close() {
+
+	close(p.IDs)
+}
+
 func newIDs(limit uint32) (p idPool) {
 
 	// sanatize limit
@@ -342,14 +350,19 @@ func (c *client) Do(req *Request) (resp *ResponsePipe, err error) {
 }
 
 // Close implements Client.Close
+//
 // If the inner connection has been closed before,
-// this method would do nothing and return nil
+// this method would do nothing and return nil.
+//
+// This will also close the IDPool.
 func (c *client) Close() (err error) {
+	// Close inner connection.
 	if c.conn == nil {
 		return
 	}
 	err = c.conn.Close()
 	c.conn = nil
+	c.ids.Close() // close the
 	return
 }
 
@@ -585,3 +598,17 @@ func (c ClientFunc) Do(req *Request) (resp *ResponsePipe, err error) {
 func (c ClientFunc) Close() error {
 	return nil
 }
+
+func recoverSendOnClosedChannel() {
+	if r := recover(); r != nil {
+		switch v := r.(type) {
+		case runtime.Error:
+			if v.Error() == "send on closed channel" {
+				// ignore
+				return
+			}
+		default:
+			panic(r)
+		}
+	}
+}

From 1893199e047cb6cf8714df313a8ebe2183f8c724 Mon Sep 17 00:00:00 2001
From: Koala Yeung <koalay@gmail.com>
Date: Thu, 18 Feb 2021 14:08:12 +0800
Subject: [PATCH 2/2] client: Fix data race in idPool usage

* There don't seem to be a need to pass idPool pointer around.
---
 client.go | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/client.go b/client.go
index 89bda2c..0bf7572 100644
--- a/client.go
+++ b/client.go
@@ -69,12 +69,12 @@ type idPool struct {
 }
 
 // AllocID implements Client.AllocID
-func (p *idPool) Alloc() (id uint16) {
+func (p idPool) Alloc() (id uint16) {
 	return <-p.IDs
 }
 
 // ReleaseID implements Client.ReleaseID
-func (p *idPool) Release(id uint16) {
+func (p idPool) Release(id uint16) {
 	go func() {
 		defer recoverSendOnClosedChannel()
 
@@ -84,8 +84,7 @@ func (p *idPool) Release(id uint16) {
 	}()
 }
 
-func (p *idPool) Close() {
-
+func (p idPool) Close() {
 	close(p.IDs)
 }