Fix an issue that blocks all waiting callers when all workers panic

Fixes #146 #147

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
 		}
 

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]

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 {

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 {