ask the request if we should show exceptions

hide the env key in the request object so that other code doesn't need
to know.

3 files changed, 13 insertions, 4 deletions

diff --git a/actionpack/lib/action_dispatch/http/request.rb b/actionpack/lib/action_dispatch/http/request.rb
index eeded9ffd0..c18c2643e4 100644
--- a/actionpack/lib/action_dispatch/http/request.rb
+++ b/actionpack/lib/action_dispatch/http/request.rb
@@ -132,6 +132,13 @@ module ActionDispatch
       end
     end
 
+    def show_exceptions? # :nodoc:
+      # We're treating `nil` as "unset", and we want the default setting to be
+      # `true`.  This logic should be extracted to `env_config` and calculated
+      # once.
+      !(env['action_dispatch.show_exceptions'.freeze] == false)
+    end
+
     # Returns a symbol form of the #request_method
     def request_method_symbol
       HTTP_METHOD_LOOKUP[request_method]
diff --git a/actionpack/lib/action_dispatch/middleware/debug_exceptions.rb b/actionpack/lib/action_dispatch/middleware/debug_exceptions.rb
index 53a025a975..226a688fe2 100644
--- a/actionpack/lib/action_dispatch/middleware/debug_exceptions.rb
+++ b/actionpack/lib/action_dispatch/middleware/debug_exceptions.rb
@@ -44,6 +44,7 @@ module ActionDispatch
     end
 
     def call(env)
+      request = ActionDispatch::Request.new env
       _, headers, body = response = @app.call(env)
 
       if headers['X-Cascade'] == 'pass'
@@ -53,7 +54,7 @@ module ActionDispatch
 
       response
     rescue Exception => exception
-      raise exception if env['action_dispatch.show_exceptions'] == false
+      raise exception unless request.show_exceptions?
       render_exception(env, exception)
     end
 
diff --git a/actionpack/lib/action_dispatch/middleware/show_exceptions.rb b/actionpack/lib/action_dispatch/middleware/show_exceptions.rb
index a764a1aea5..12d8dab8eb 100644
--- a/actionpack/lib/action_dispatch/middleware/show_exceptions.rb
+++ b/actionpack/lib/action_dispatch/middleware/show_exceptions.rb
@@ -27,12 +27,13 @@ module ActionDispatch
     end
 
     def call(env)
+      request = ActionDispatch::Request.new env
       @app.call(env)
     rescue Exception => exception
-      if env['action_dispatch.show_exceptions'] == false
-        raise exception
-      else
+      if request.show_exceptions?
         render_exception(env, exception)
+      else
+        raise exception
       end
     end