From b06fb15461e2cb4cfcba3a68236e1bd028598196 Mon Sep 17 00:00:00 2001
From: Michael Lutsiuk <mmaccoffe@gmail.com>
Date: Sun, 15 Feb 2015 02:52:28 +0200
Subject: [PATCH 1/3] Fix deadlock when passing same connection

---
 lib/redis/semaphore.rb |  6 +++++-
 spec/semaphore_spec.rb | 19 ++++++++++++++++++-
 spec/spec_helper.rb    |  1 +
 3 files changed, 24 insertions(+), 2 deletions(-)

diff --git a/lib/redis/semaphore.rb b/lib/redis/semaphore.rb
index 22e1645..1aaeec2 100644
--- a/lib/redis/semaphore.rb
+++ b/lib/redis/semaphore.rb
@@ -19,8 +19,12 @@ def initialize(name, opts = {})
       @expiration = opts.delete(:expiration)
       @resource_count = opts.delete(:resources) || 1
       @stale_client_timeout = opts.delete(:stale_client_timeout)
-      @redis = opts.delete(:redis) || Redis.new(opts)
       @use_local_time = opts.delete(:use_local_time)
+      @redis = if @redis = opts.delete(:redis)
+                 @redis.dup
+               else
+                 Redis.new(opts)
+               end
       @tokens = []
     end
 
diff --git a/spec/semaphore_spec.rb b/spec/semaphore_spec.rb
index 75fdbd3..dac4967 100644
--- a/spec/semaphore_spec.rb
+++ b/spec/semaphore_spec.rb
@@ -125,6 +125,23 @@
 
       expect(@redis.keys.count).to eq(original_key_size)
     end
+
+    it "don't enters deadlock" do
+      i = 0
+      expect {
+        redis = @redis.dup
+        Timeout.timeout(2) do
+          Array.new(2).map do
+            Thread.new do
+              Redis::Semaphore.new(:sem, redis: redis).lock do
+                i += 1
+              end
+            end
+          end.each(&:join)
+        end
+      }.not_to raise_error
+      expect(i).to eq(2)
+    end
   end
 
   describe "semaphore with expiration" do
@@ -211,7 +228,7 @@
     end
 
     it "without time support should return the same time as frozen time" do
-      expect(@redis).to receive(:time).and_raise(Redis::CommandError)
+      expect(semaphore.instance_variable_get(:@redis)).to receive(:time).and_raise(Redis::CommandError)
       expect(semaphore.send(:current_time)).to eq(Time.now)
     end
   end
diff --git a/spec/spec_helper.rb b/spec/spec_helper.rb
index 1eff8be..05a660a 100644
--- a/spec/spec_helper.rb
+++ b/spec/spec_helper.rb
@@ -4,4 +4,5 @@
 
 $TESTING=true
 $:.unshift File.join(File.dirname(__FILE__), '..', 'lib')
+require 'timeout'
 require 'redis/semaphore'

From 54a1c663d19978a3415583339ece0d67af8d78e7 Mon Sep 17 00:00:00 2001
From: Michael Lutsiuk <mmaccoffe@gmail.com>
Date: Sun, 15 Feb 2015 02:55:41 +0200
Subject: [PATCH 2/3] Make #create! independent from calls to another methods

---
 lib/redis/semaphore.rb | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/lib/redis/semaphore.rb b/lib/redis/semaphore.rb
index 1aaeec2..2cbec4f 100644
--- a/lib/redis/semaphore.rb
+++ b/lib/redis/semaphore.rb
@@ -29,7 +29,7 @@ def initialize(name, opts = {})
     end
 
     def exists_or_create!
-      token = @redis.getset(exists_key, EXISTS_TOKEN)
+      token = @redis.get(exists_key)
 
       if token.nil?
         create!
@@ -160,7 +160,7 @@ def simple_mutex(key_name, expires = nil)
     end
 
     def create!
-      @redis.expire(exists_key, 10)
+      @redis.setex(exists_key, 10, EXISTS_TOKEN)
 
       @redis.multi do
         @redis.del(grabbed_key)

From 19d6f119910fd150fece32b5c4b29c34b3fd054a Mon Sep 17 00:00:00 2001
From: Michael Lutsiuk <mmaccoffe@gmail.com>
Date: Sun, 15 Feb 2015 02:56:51 +0200
Subject: [PATCH 3/3] Can use less code here. Avoid return in block definition

---
 lib/redis/semaphore.rb | 6 +-----
 spec/semaphore_spec.rb | 3 ++-
 2 files changed, 3 insertions(+), 6 deletions(-)

diff --git a/lib/redis/semaphore.rb b/lib/redis/semaphore.rb
index 2cbec4f..590da03 100644
--- a/lib/redis/semaphore.rb
+++ b/lib/redis/semaphore.rb
@@ -94,11 +94,7 @@ def locked?(token = nil)
       if token
         @redis.hexists(grabbed_key, token)
       else
-        @tokens.each do |token|
-          return true if locked?(token)
-        end
-
-        false
+        @tokens.any? { |t| locked?(t) }
       end
     end
 
diff --git a/spec/semaphore_spec.rb b/spec/semaphore_spec.rb
index dac4967..3da7b23 100644
--- a/spec/semaphore_spec.rb
+++ b/spec/semaphore_spec.rb
@@ -228,7 +228,8 @@
     end
 
     it "without time support should return the same time as frozen time" do
-      expect(semaphore.instance_variable_get(:@redis)).to receive(:time).and_raise(Redis::CommandError)
+      expect(semaphore.instance_variable_get(:@redis)).to receive(:time)
+        .and_raise(Redis::CommandError)
       expect(semaphore.send(:current_time)).to eq(Time.now)
     end
   end