From cfc2a383ac48f5324263e8d34ca8afcb3f58a085 Mon Sep 17 00:00:00 2001
From: sampatbadhe <sampatbadhe@gmail.com>
Date: Sat, 19 Feb 2022 13:47:03 +0530
Subject: [PATCH 1/2] add guard against releasing slots that haven't been
 reserved

---
 lib/kredis/types/slots.rb | 11 ++++++++---
 test/types/slots_test.rb  | 25 +++++++++++++++++++++++++
 2 files changed, 33 insertions(+), 3 deletions(-)

diff --git a/lib/kredis/types/slots.rb b/lib/kredis/types/slots.rb
index 5909d30..11fff0e 100644
--- a/lib/kredis/types/slots.rb
+++ b/lib/kredis/types/slots.rb
@@ -19,10 +19,10 @@ def reserve
           release
         end
       else
-        if incr <= available
+        if available?
+          incr
           true
         else
-          release
           false
         end
       end
@@ -30,7 +30,12 @@ def reserve
   end
 
   def release
-    decr
+    if get.to_i > 0
+      decr
+      true
+    else
+      false
+    end
   end
 
   def available?
diff --git a/test/types/slots_test.rb b/test/types/slots_test.rb
index c12b277..3cf2ebc 100644
--- a/test/types/slots_test.rb
+++ b/test/types/slots_test.rb
@@ -26,6 +26,20 @@ class SlotsTest < ActiveSupport::TestCase
     assert @slots.available?
   end
 
+  test 'release when slots are reserved' do
+    assert_not @slots.release
+
+    3.times do
+      assert @slots.reserve
+    end
+
+    3.times do
+      assert @slots.release
+    end
+
+    assert_not @slots.release
+  end
+
   test "reserve with block" do
     assert @slots.reserve
     assert @slots.reserve
@@ -70,6 +84,17 @@ class SlotsTest < ActiveSupport::TestCase
     assert_not slot.available?
   end
 
+  test "release single slot when reserved" do
+    slot = Kredis.slot "myslot"
+
+    assert_not slot.release
+
+    assert slot.reserve
+    assert slot.release
+
+    assert_not slot.release
+  end
+
   test "failing open" do
     stub_redis_down(@slots) do
       assert_not @slots.available?

From 3e366914db301361dd3784eb3df6d7bebdd93e78 Mon Sep 17 00:00:00 2001
From: David Heinemeier Hansson <david@hey.com>
Date: Sat, 19 Feb 2022 14:21:43 +0100
Subject: [PATCH 2/2] Add Slots#taken method

---
 lib/kredis/types/slots.rb | 8 ++++++--
 test/types/slots_test.rb  | 4 +++-
 2 files changed, 9 insertions(+), 3 deletions(-)

diff --git a/lib/kredis/types/slots.rb b/lib/kredis/types/slots.rb
index 11fff0e..94c5286 100644
--- a/lib/kredis/types/slots.rb
+++ b/lib/kredis/types/slots.rb
@@ -30,7 +30,7 @@ def reserve
   end
 
   def release
-    if get.to_i > 0
+    if taken > 0
       decr
       true
     else
@@ -40,11 +40,15 @@ def release
 
   def available?
     failsafe returning: false do
-      get.to_i < available
+      taken < available
     end
   end
 
   def reset
     del
   end
+
+  def taken
+    get.to_i
+  end
 end
diff --git a/test/types/slots_test.rb b/test/types/slots_test.rb
index 3cf2ebc..ef11204 100644
--- a/test/types/slots_test.rb
+++ b/test/types/slots_test.rb
@@ -26,7 +26,7 @@ class SlotsTest < ActiveSupport::TestCase
     assert @slots.available?
   end
 
-  test 'release when slots are reserved' do
+  test "release when slots are reserved" do
     assert_not @slots.release
 
     3.times do
@@ -38,6 +38,8 @@ class SlotsTest < ActiveSupport::TestCase
     end
 
     assert_not @slots.release
+
+    assert_equal 0, @slots.taken
   end
 
   test "reserve with block" do