From 0ed321b09408dba82fcf5bfd2be62b6556faee38 Mon Sep 17 00:00:00 2001
From: Yohei Kitamura <ykitamura@mdsol.com>
Date: Thu, 8 Oct 2020 14:02:12 -0400
Subject: [PATCH] Reset @cache_control in Response when duplicating its
 instance

---
 lib/rack/cache/response.rb |  1 +
 test/context_test.rb       | 23 +++++++++++++++++++++++
 2 files changed, 24 insertions(+)

diff --git a/lib/rack/cache/response.rb b/lib/rack/cache/response.rb
index 443be06..eff8da3 100644
--- a/lib/rack/cache/response.rb
+++ b/lib/rack/cache/response.rb
@@ -40,6 +40,7 @@ def initialize(status, headers, body)
     def initialize_copy(other)
       super
       @headers = other.headers.dup
+      @cache_control = nil
     end
 
     # Return the status, headers, and body in a three-tuple.
diff --git a/test/context_test.rb b/test/context_test.rb
index 7351b75..8252483 100644
--- a/test/context_test.rb
+++ b/test/context_test.rb
@@ -992,6 +992,29 @@
     cache.trace.must_include :pass
   end
 
+  it 'does not cache when Cache-Control response header changed to private (reset @cache_control on dup)' do
+    count = 0
+    respond_with do |req,res|
+      count+= 1
+      res['Cache-Control'] = (count == 1) ? 'public' : 'private, no-store'
+      res['ETag'] = count.to_s
+      res.status = (count == 1) ? 200 : 304
+    end
+
+    get '/'
+    assert app.called?
+    assert response.ok?
+    cache.trace.must_include :miss
+    cache.trace.must_include :store
+
+    get '/'
+    assert app.called?
+    assert response.ok?
+    cache.trace.must_include :stale
+    cache.trace.must_include :valid
+    cache.trace.wont_include :store
+  end
+
   it 'logs to rack.logger if available' do
     logger = Class.new do
       attr_reader :logged_level