From 5be3611ff3540990013fb54d27482ccc344a557f Mon Sep 17 00:00:00 2001
From: Aaron Patterson <aaron.patterson@gmail.com>
Date: Tue, 9 Apr 2019 13:20:26 -0700
Subject: [PATCH] fix memory leak introduced by connection pooling

5bae22e8a3626ab3b14743c00796d4f176580ad8 introduced a memory leak when
it switched to connection pooling.  We're setting a thread local but
then never clearing the local.  If the pool is used in the main thread,
it will never die and the locals will stick around for the life of the
process.

Here is the program I used to test:

```
require 'net/http/persistent'

def run2
  1000.times do
    uri = URI 'http://localhost:5000'
    http = Net::HTTP::Persistent.new name: 'my_app_name'
    # perform a GET
    response = http.request uri
    # if you are done making http requests, or won't make requests for several
    # minutes
    http.shutdown
  end
end

p Thread.current.keys
run2
p Thread.current.keys
```
---
 lib/net/http/persistent.rb      |  4 +---
 lib/net/http/persistent/pool.rb | 12 ++++++++----
 2 files changed, 9 insertions(+), 7 deletions(-)

diff --git a/lib/net/http/persistent.rb b/lib/net/http/persistent.rb
index e1fadbc..ad66842 100644
--- a/lib/net/http/persistent.rb
+++ b/lib/net/http/persistent.rb
@@ -1048,9 +1048,7 @@ def request_setup req_or_uri # :nodoc:
   # #shutdown when you are completely done making requests!
 
   def shutdown
-    @pool.available.shutdown do |http|
-      http.finish
-    end
+    @pool.shutdown { |http| http.finish }
   end
 
   ##
diff --git a/lib/net/http/persistent/pool.rb b/lib/net/http/persistent/pool.rb
index b88dd59..90fd92b 100644
--- a/lib/net/http/persistent/pool.rb
+++ b/lib/net/http/persistent/pool.rb
@@ -7,11 +7,11 @@ def initialize(options = {}, &block)
     super
 
     @available = Net::HTTP::Persistent::TimedStackMulti.new(@size, &block)
-    @key = :"current-#{@available.object_id}"
+    @key = "current-#{@available.object_id}"
   end
 
   def checkin net_http_args
-    stack = Thread.current[@key][net_http_args]
+    stack = Thread.current[@key][net_http_args] ||= []
 
     raise ConnectionPool::Error, 'no connections are checked out' if
       stack.empty?
@@ -26,8 +26,8 @@ def checkin net_http_args
   end
 
   def checkout net_http_args
-    stacks = Thread.current[@key] ||= Hash.new { |h, k| h[k] = [] }
-    stack  = stacks[net_http_args]
+    stacks = Thread.current[@key] ||= {}
+    stack  = stacks[net_http_args] ||= []
 
     if stack.empty? then
       conn = @available.pop connection_args: net_http_args
@@ -40,6 +40,10 @@ def checkout net_http_args
     conn
   end
 
+  def shutdown
+    Thread.current[@key] = nil
+    super
+  end
 end
 
 require 'net/http/persistent/timed_stack_multi'