From dbcb6a104f23b1a6a7521796b30515230353283e Mon Sep 17 00:00:00 2001
From: Andy Pan <panjf2000@gmail.com>
Date: Sun, 28 Mar 2021 22:37:56 +0800
Subject: [PATCH] Fix an issue that blocks all waiting callers when all workers
 panic

Fixes #146 #147
---
 pool.go        | 12 ++++++++----
 pool_func.go   |  5 +++++
 worker.go      |  2 ++
 worker_func.go |  2 ++
 4 files changed, 17 insertions(+), 4 deletions(-)

diff --git a/pool.go b/pool.go
index e27d586..37151cc 100644
--- a/pool.go
+++ b/pool.go
@@ -243,16 +243,20 @@ func (p *Pool) retrieveWorker() (w *goWorker) {
 		p.blockingNum++
 		p.cond.Wait()
 		p.blockingNum--
-		if p.Running() == 0 {
+		var nw int
+		if nw = p.Running(); nw == 0 {
 			p.lock.Unlock()
 			if !p.IsClosed() {
 				spawnWorker()
 			}
 			return
 		}
-
-		w = p.workers.detach()
-		if w == nil {
+		if w = p.workers.detach(); w == nil {
+			if nw < capacity {
+				p.lock.Unlock()
+				spawnWorker()
+				return
+			}
 			goto Reentry
 		}
 
diff --git a/pool_func.go b/pool_func.go
index 3d77487..b14be42 100644
--- a/pool_func.go
+++ b/pool_func.go
@@ -270,6 +270,11 @@ func (p *PoolWithFunc) retrieveWorker() (w *goWorkerWithFunc) {
 		}
 		l := len(p.workers) - 1
 		if l < 0 {
+			if p.Running() < p.Cap() {
+				p.lock.Unlock()
+				spawnWorker()
+				return
+			}
 			goto Reentry
 		}
 		w = p.workers[l]
diff --git a/worker.go b/worker.go
index 1a52d65..3fb8333 100644
--- a/worker.go
+++ b/worker.go
@@ -59,6 +59,8 @@ func (w *goWorker) run() {
 					w.pool.options.Logger.Printf("worker exits from panic: %s\n", string(buf[:n]))
 				}
 			}
+			// Call Signal() here in case there are goroutines waiting for available workers.
+			w.pool.cond.Signal()
 		}()
 
 		for f := range w.task {
diff --git a/worker_func.go b/worker_func.go
index 14a63c2..a123dc3 100644
--- a/worker_func.go
+++ b/worker_func.go
@@ -59,6 +59,8 @@ func (w *goWorkerWithFunc) run() {
 					w.pool.options.Logger.Printf("worker with func exits from panic: %s\n", string(buf[:n]))
 				}
 			}
+			// Call Signal() here in case there are goroutines waiting for available workers.
+			w.pool.cond.Signal()
 		}()
 
 		for args := range w.args {