From 7566e46e2e6120def0b84b488449ea1f419241ba Mon Sep 17 00:00:00 2001
From: daurnimator <quae@daurnimator.com>
Date: Sat, 18 Feb 2017 16:51:38 +1100
Subject: [PATCH 1/3] dns.resolvers: Use resolver from pool if there is
 something in pool

Previously this would always leave/ignore one resolver in the pool
---
 src/dns.resolvers.lua | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/dns.resolvers.lua b/src/dns.resolvers.lua
index 4c671ed..9180bab 100644
--- a/src/dns.resolvers.lua
+++ b/src/dns.resolvers.lua
@@ -115,7 +115,7 @@ local loader = function(loader, ...)
 		local res
 		while true do
 			local cache_len = #self.cache
-			if cache_len > 1 then
+			if cache_len > 0 then
 				res = self.cache[cache_len]
 				self.cache[cache_len] = nil
 				if res then

From 1bcd9f41a2419e69d1a974f13de273b829288823 Mon Sep 17 00:00:00 2001
From: daurnimator <quae@daurnimator.com>
Date: Sat, 18 Feb 2017 16:53:12 +1100
Subject: [PATCH 2/3] dns.resolvers: Avoid potential infinite loop waiting for
 a resolver

Previously if there was nothing in pool but more than hiwat resolvers alive, then this would busy loop (not even yielding)
---
 src/dns.resolvers.lua | 12 ++++--------
 1 file changed, 4 insertions(+), 8 deletions(-)

diff --git a/src/dns.resolvers.lua b/src/dns.resolvers.lua
index 9180bab..ecdff5b 100644
--- a/src/dns.resolvers.lua
+++ b/src/dns.resolvers.lua
@@ -118,14 +118,7 @@ local loader = function(loader, ...)
 			if cache_len > 0 then
 				res = self.cache[cache_len]
 				self.cache[cache_len] = nil
-				if res then
-					break
-				else
-					if deadline and deadline <= monotime() then
-						return nil, ETIMEDOUT
-					end
-					self.condvar:wait(totimeout(deadline))
-				end
+				break
 			elseif self.alive.n < self.hiwat then
 				local why
 				res, why = resolver.new(self.resconf, self.hosts, self.hints)
@@ -134,6 +127,9 @@ local loader = function(loader, ...)
 				end
 				break
 			end
+			if not self.condvar:wait(totimeout(deadline)) then
+				return nil, ETIMEDOUT
+			end
 		end
 		self.alive:add(res)
 		return res

From d3ec712a873475cc275a9e5c5570201b99540dd7 Mon Sep 17 00:00:00 2001
From: daurnimator <quae@daurnimator.com>
Date: Sat, 18 Feb 2017 17:17:12 +1100
Subject: [PATCH 3/3] Add regression test for issue #178

---
 regress/178-last-resolver.lua | 14 ++++++++++++++
 1 file changed, 14 insertions(+)
 create mode 100755 regress/178-last-resolver.lua

diff --git a/regress/178-last-resolver.lua b/regress/178-last-resolver.lua
new file mode 100755
index 0000000..601542b
--- /dev/null
+++ b/regress/178-last-resolver.lua
@@ -0,0 +1,14 @@
+#!/bin/sh
+_=[[
+	. "${0%%/*}/regress.sh"
+	exec runlua "$0" "$@"
+]]
+require"regress".export".*"
+
+local pool = dns.getpool()
+local r = pool:get()
+pool:put(r)
+local q = pool:get()
+check(r == q, "resolver not reused")
+
+say"OK"