Fix queued checkout after a connection failure

index.js

@@ -226,6 +226,10 @@ class Pool extends EventEmitter {
         if (timeoutHit) {
           err.message = 'Connection terminated due to connection timeout'
         }
+
+        // this client won’t be released, so move on immediately
+        this._pulseQueue()
+
         cb(err, undefined, NOOP)
       } else {
         this.log('new client connected')

test/error-handling.js

@@ -1,4 +1,5 @@
 'use strict'
+const net = require('net')
 const co = require('co')
 const expect = require('expect.js')
 
@@ -143,4 +144,25 @@ describe('pool error handling', function () {
       return pool.end()
     }))
   })
+
+  it('should continue with queued items after a connection failure', (done) => {
+    const closeServer = net.createServer((socket) => {
+      socket.destroy()
+    }).unref()
+
+    closeServer.listen(() => {
+      const pool = new Pool({ max: 1, port: closeServer.address().port })
+      pool.connect((err) => {
+        expect(err).to.be.an(Error)
+        expect(err.message).to.be('Connection terminated unexpectedly')
+      })
+      pool.connect((err) => {
+        expect(err).to.be.an(Error)
+        expect(err.message).to.be('Connection terminated unexpectedly')
+        closeServer.close(() => {
+          pool.end(done)
+        })
+      })
+    })
+  })
 })