avoid reusing env on hijack

Hijackers may capture and reuse `env' indefinitely, so we must
not use it in those cases for future requests.  For non-hijack
requests, we continue to reuse the `env' object to reduce
memory recycling.

Reported-and-tested-by: Sam Saffron <sam.saffron@gmail.com>

2 files changed, 34 insertions, 1 deletions

diff --git a/t/hijack.ru b/t/hijack.ru
index 4adec61..02260e2 100644
--- a/t/hijack.ru
+++ b/t/hijack.ru
@@ -11,11 +11,15 @@ class DieIfUsed
     warn "closed DieIfUsed #{@@n += 1}\n"
   end
 end
+
+envs = []
+
 run lambda { |env|
   case env["PATH_INFO"]
   when "/hijack_req"
     if env["rack.hijack?"]
       io = env["rack.hijack"].call
+      envs << env
       if io.respond_to?(:read_nonblock) &&
          env["rack.hijack_io"].respond_to?(:read_nonblock)
 
@@ -33,11 +37,19 @@ run lambda { |env|
       {
         "Content-Length" => r.bytesize.to_s,
         "rack.hijack" => proc do |io|
+          envs << env
           io.write(r)
           io.close
         end
       },
       DieIfUsed.new
     ]
+  when "/normal_env_id"
+    b = "#{env.object_id}\n"
+    h = {
+      'Content-Type' => 'text/plain',
+      'Content-Length' => b.bytesize.to_s,
+    }
+    [ 200, h, [ b ] ]
   end
 }
diff --git a/t/t0200-rack-hijack.sh b/t/t0200-rack-hijack.sh
index de3eb82..fee0791 100755
--- a/t/t0200-rack-hijack.sh
+++ b/t/t0200-rack-hijack.sh
@@ -1,6 +1,6 @@
 #!/bin/sh
 . ./test-lib.sh
-t_plan 5 "rack.hijack tests (Rack 1.5+ (Rack::VERSION >= [ 1,2]))"
+t_plan 9 "rack.hijack tests (Rack 1.5+ (Rack::VERSION >= [ 1,2]))"
 
 t_begin "setup and start" && {
         unicorn_setup
@@ -8,14 +8,35 @@ t_begin "setup and start" && {
         unicorn_wait_start
 }
 
+t_begin "normal env reused between requests" && {
+        env_a="$(curl -sSf http://$listen/normal_env_id)"
+        b="$(curl -sSf http://$listen/normal_env_id)"
+        test x"$env_a" = x"$b"
+}
+
 t_begin "check request hijack" && {
         test "xrequest.hijacked" = x"$(curl -sSfv http://$listen/hijack_req)"
 }
 
+t_begin "env changed after request hijack" && {
+        env_b="$(curl -sSf http://$listen/normal_env_id)"
+        test x"$env_a" != x"$env_b"
+}
+
 t_begin "check response hijack" && {
         test "xresponse.hijacked" = x"$(curl -sSfv http://$listen/hijack_res)"
 }
 
+t_begin "env changed after response hijack" && {
+        env_c="$(curl -sSf http://$listen/normal_env_id)"
+        test x"$env_b" != x"$env_c"
+}
+
+t_begin "env continues to be reused between requests" && {
+        b="$(curl -sSf http://$listen/normal_env_id)"
+        test x"$env_c" = x"$b"
+}
+
 t_begin "killing succeeds after hijack" && {
         kill $unicorn_pid
 }