From 05bff0b2c130547353e4d5ca699211cbe3ba1cd8 Mon Sep 17 00:00:00 2001
From: Daniel Gomes <me@danielcsgomes.com>
Date: Tue, 4 Jul 2017 00:53:41 +0100
Subject: [PATCH 1/8] Bubbles up to the error_formatter the root exception when
 a custom parser is not able to parse a json input body.

---
 lib/grape/middleware/formatter.rb | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/grape/middleware/formatter.rb b/lib/grape/middleware/formatter.rb
index 1e21619b0..eadbe2cbf 100644
--- a/lib/grape/middleware/formatter.rb
+++ b/lib/grape/middleware/formatter.rb
@@ -110,7 +110,7 @@ def read_rack_input(body)
           rescue Grape::Exceptions::Base => e
             raise e
           rescue StandardError => e
-            throw :error, status: 400, message: e.message
+            throw :error, status: 400, message: e.message, backtrace: e
           end
         else
           env[Grape::Env::API_REQUEST_BODY] = body

From 25b1dcd82e45de1dc853fb02bc2208e620d0baf3 Mon Sep 17 00:00:00 2001
From: Daniel Gomes <me@danielcsgomes.com>
Date: Tue, 4 Jul 2017 01:23:36 +0100
Subject: [PATCH 2/8] update the changelog

---
 CHANGELOG.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 9cbb0ffa5..bd97427f7 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -6,7 +6,7 @@
 
 #### Fixes
 
-* Your contribution here.
+* [#1652](https://github.com/ruby-grape/grape/pull/1652): Bubble up to the error_formatter the root exception - [@dcsg](https://github.com/dcsg).
 
 ### 1.0.0 (7/3/2017)
 

From 93670da0aa5fc8db906a8af3895e05d776f6b24b Mon Sep 17 00:00:00 2001
From: Daniel Gomes <me@danielcsgomes.com>
Date: Thu, 6 Jul 2017 00:50:08 +0100
Subject: [PATCH 3/8] Add exception to the `formatter.call` contract Add
 backtrace in missing `throw :error` Add tests

---
 lib/grape/error_formatter/json.rb       |  3 ++-
 lib/grape/error_formatter/txt.rb        |  3 ++-
 lib/grape/error_formatter/xml.rb        |  3 ++-
 lib/grape/middleware/error.rb           | 24 ++++++++++++++--------
 lib/grape/middleware/formatter.rb       |  4 ++--
 spec/grape/api_spec.rb                  |  4 ++--
 spec/grape/middleware/exception_spec.rb | 27 ++++++++++++++++++-------
 7 files changed, 46 insertions(+), 22 deletions(-)

diff --git a/lib/grape/error_formatter/json.rb b/lib/grape/error_formatter/json.rb
index e11210495..9e012bc65 100644
--- a/lib/grape/error_formatter/json.rb
+++ b/lib/grape/error_formatter/json.rb
@@ -4,12 +4,13 @@ module Json
       extend Base
 
       class << self
-        def call(message, backtrace, options = {}, env = nil)
+        def call(message, backtrace, options = {}, env = nil, exception = '')
           result = wrap_message(present(message, env))
 
           if (options[:rescue_options] || {})[:backtrace] && backtrace && !backtrace.empty?
             result = result.merge(backtrace: backtrace)
           end
+          result = result.merge(exception: exception) if (options[:rescue_options] || {})[:exception] && !exception.empty?
           ::Grape::Json.dump(result)
         end
 
diff --git a/lib/grape/error_formatter/txt.rb b/lib/grape/error_formatter/txt.rb
index db8762f95..59a09d1a5 100644
--- a/lib/grape/error_formatter/txt.rb
+++ b/lib/grape/error_formatter/txt.rb
@@ -4,7 +4,7 @@ module Txt
       extend Base
 
       class << self
-        def call(message, backtrace, options = {}, env = nil)
+        def call(message, backtrace, options = {}, env = nil, exception = '')
           message = present(message, env)
 
           result = message.is_a?(Hash) ? ::Grape::Json.dump(message) : message
@@ -12,6 +12,7 @@ def call(message, backtrace, options = {}, env = nil)
             result += "\r\n "
             result += backtrace.join("\r\n ")
           end
+          result += "\r\n #{exception}" if (options[:rescue_options] || {})[:exception] && !exception.empty?
           result
         end
       end
diff --git a/lib/grape/error_formatter/xml.rb b/lib/grape/error_formatter/xml.rb
index ea2eb3951..e29037ee3 100644
--- a/lib/grape/error_formatter/xml.rb
+++ b/lib/grape/error_formatter/xml.rb
@@ -4,13 +4,14 @@ module Xml
       extend Base
 
       class << self
-        def call(message, backtrace, options = {}, env = nil)
+        def call(message, backtrace, options = {}, env = nil, exception = '')
           message = present(message, env)
 
           result = message.is_a?(Hash) ? message : { message: message }
           if (options[:rescue_options] || {})[:backtrace] && backtrace && !backtrace.empty?
             result = result.merge(backtrace: backtrace)
           end
+          result = result.merge(exception: exception) if (options[:rescue_options] || {})[:exception] && !exception.empty?
           result.respond_to?(:to_xml) ? result.to_xml(root: :error) : result.to_s
         end
       end
diff --git a/lib/grape/middleware/error.rb b/lib/grape/middleware/error.rb
index dcf6e0144..4b6c3184a 100644
--- a/lib/grape/middleware/error.rb
+++ b/lib/grape/middleware/error.rb
@@ -14,7 +14,10 @@ def default_options
           rescue_all: false, # true to rescue all exceptions
           rescue_grape_exceptions: false,
           rescue_subclasses: true, # rescue subclasses of exceptions listed
-          rescue_options: { backtrace: false }, # true to display backtrace, true to let Grape handle Grape::Exceptions
+          rescue_options: {
+            backtrace: false, # true to display backtrace, true to let Grape handle Grape::Exceptions
+            exception: false, # true to display exception
+          },
           rescue_handlers: {}, # rescue handler blocks
           base_only_rescue_handlers: {}, # rescue handler blocks rescuing only the base class
           all_rescue_handler: nil # rescue handler block to rescue from all exceptions
@@ -77,13 +80,13 @@ def exec_handler(e, &handler)
         end
       end
 
-      def error!(message, status = options[:default_status], headers = {}, backtrace = [])
+      def error!(message, status = options[:default_status], headers = {}, backtrace = [], exception = '')
         headers = headers.reverse_merge(Grape::Http::Headers::CONTENT_TYPE => content_type)
-        rack_response(format_message(message, backtrace), status, headers)
+        rack_response(format_message(message, backtrace, exception), status, headers)
       end
 
       def handle_error(e)
-        error_response(message: e.message, backtrace: e.backtrace)
+        error_response(message: e.message, backtrace: e.backtrace, exception: e.class.name)
       end
 
       # TODO: This method is deprecated. Refactor out.
@@ -93,18 +96,23 @@ def error_response(error = {})
         headers = { Grape::Http::Headers::CONTENT_TYPE => content_type }
         headers.merge!(error[:headers]) if error[:headers].is_a?(Hash)
         backtrace = error[:backtrace] || []
-        rack_response(format_message(message, backtrace), status, headers)
+        exception = error.is_a?(Exception) ? error.class.name : error[:exception] || ''
+        rack_response(format_message(message, backtrace, exception), status, headers)
       end
 
       def rack_response(message, status = options[:default_status], headers = { Grape::Http::Headers::CONTENT_TYPE => content_type })
         Rack::Response.new([message], status, headers).finish
       end
 
-      def format_message(message, backtrace)
+      def format_message(message, backtrace, exception)
         format = env[Grape::Env::API_FORMAT] || options[:format]
         formatter = Grape::ErrorFormatter.formatter_for(format, options)
-        throw :error, status: 406, message: "The requested format '#{format}' is not supported." unless formatter
-        formatter.call(message, backtrace, options, env)
+        throw :error,
+              status: 406,
+              message: "The requested format '#{format}' is not supported.",
+              backtrace: backtrace,
+              exception: exception unless formatter
+        formatter.call(message, backtrace, options, env, exception)
       end
 
       private
diff --git a/lib/grape/middleware/formatter.rb b/lib/grape/middleware/formatter.rb
index eadbe2cbf..2970f83dd 100644
--- a/lib/grape/middleware/formatter.rb
+++ b/lib/grape/middleware/formatter.rb
@@ -45,7 +45,7 @@ def build_formatted_response(status, headers, bodies)
           Rack::Response.new(bodymap, status, headers)
         end
       rescue Grape::Exceptions::InvalidFormatter => e
-        throw :error, status: 500, message: e.message
+        throw :error, status: 500, message: e.message, backtrace: e.backtrace, exception: e
       end
 
       def fetch_formatter(headers, options)
@@ -110,7 +110,7 @@ def read_rack_input(body)
           rescue Grape::Exceptions::Base => e
             raise e
           rescue StandardError => e
-            throw :error, status: 400, message: e.message, backtrace: e
+            throw :error, status: 400, message: e.message, backtrace: e.backtrace, exception: e
           end
         else
           env[Grape::Env::API_REQUEST_BODY] = body
diff --git a/spec/grape/api_spec.rb b/spec/grape/api_spec.rb
index 779893f8e..9cda20500 100644
--- a/spec/grape/api_spec.rb
+++ b/spec/grape/api_spec.rb
@@ -1996,7 +1996,7 @@ class ChildError < ParentError; end
       before :each do
         module ApiSpec
           class CustomErrorFormatter
-            def self.call(message, _backtrace, _options, _env)
+            def self.call(message, _backtrace, _options, _env, _exception)
               "message: #{message} @backtrace"
             end
           end
@@ -2018,7 +2018,7 @@ def self.call(message, _backtrace, _options, _env)
         before :each do
           module ApiSpec
             class CustomErrorFormatter
-              def self.call(message, _backtrace, _option, _env)
+              def self.call(message, _backtrace, _option, _env, _exception)
                 "message: #{message} @backtrace"
               end
             end
diff --git a/spec/grape/middleware/exception_spec.rb b/spec/grape/middleware/exception_spec.rb
index 362cc3eba..fc933558c 100644
--- a/spec/grape/middleware/exception_spec.rb
+++ b/spec/grape/middleware/exception_spec.rb
@@ -158,13 +158,14 @@ def call(_env)
     it 'is possible to specify a custom formatter' do
       @app ||= Rack::Builder.app do
         use Spec::Support::EndpointFaker
-        use Grape::Middleware::Error, rescue_all: true,
-                                      format: :custom,
-                                      error_formatters: {
-                                        custom: lambda do |message, _backtrace, _options, _env|
-                                          { custom_formatter: message }.inspect
-                                        end
-                                      }
+        use Grape::Middleware::Error,
+            rescue_all: true,
+            format: :custom,
+            error_formatters: {
+              custom: lambda do |message, _backtrace, _options, _env, _exception|
+                { custom_formatter: message }.inspect
+              end
+            }
         run ExceptionSpec::ExceptionApp
       end
       get '/'
@@ -192,5 +193,17 @@ def call(_env)
       expect(last_response.status).to eq(400)
       expect(last_response.body).to eq('failed validation')
     end
+
+    context 'with rescue_options :backtrace and :exception set to true' do
+      it 'is possible to return the backtrace and exception in json format' do
+        @app ||= Rack::Builder.app do
+          use Spec::Support::EndpointFaker
+          use Grape::Middleware::Error, rescue_all: true, format: :json, rescue_options: { backtrace: true, exception: true }
+          run ExceptionSpec::ExceptionApp
+        end
+        get '/'
+        expect(last_response.body).to include('error', 'rain!', 'backtrace', 'exception', 'RuntimeError')
+      end
+    end
   end
 end

From 2c90e6f081c3917c1648edf47baf8afc83a11e33 Mon Sep 17 00:00:00 2001
From: Daniel Gomes <me@danielcsgomes.com>
Date: Thu, 6 Jul 2017 22:37:31 +0100
Subject: [PATCH 4/8] Refactor exception to original_exception.

---
 lib/grape/error_formatter/json.rb       |  6 ++++--
 lib/grape/error_formatter/txt.rb        |  6 ++++--
 lib/grape/error_formatter/xml.rb        |  6 ++++--
 lib/grape/middleware/error.rb           | 20 ++++++++++----------
 spec/grape/middleware/exception_spec.rb |  9 ++++++---
 5 files changed, 28 insertions(+), 19 deletions(-)

diff --git a/lib/grape/error_formatter/json.rb b/lib/grape/error_formatter/json.rb
index 9e012bc65..7525eda06 100644
--- a/lib/grape/error_formatter/json.rb
+++ b/lib/grape/error_formatter/json.rb
@@ -4,13 +4,15 @@ module Json
       extend Base
 
       class << self
-        def call(message, backtrace, options = {}, env = nil, exception = '')
+        def call(message, backtrace, options = {}, env = nil, original_exception = nil)
           result = wrap_message(present(message, env))
 
           if (options[:rescue_options] || {})[:backtrace] && backtrace && !backtrace.empty?
             result = result.merge(backtrace: backtrace)
           end
-          result = result.merge(exception: exception) if (options[:rescue_options] || {})[:exception] && !exception.empty?
+          if (options[:rescue_options] || {})[:original_exception] && original_exception
+            result = result.merge(original_exception: original_exception.inspect)
+          end
           ::Grape::Json.dump(result)
         end
 
diff --git a/lib/grape/error_formatter/txt.rb b/lib/grape/error_formatter/txt.rb
index 59a09d1a5..210115e26 100644
--- a/lib/grape/error_formatter/txt.rb
+++ b/lib/grape/error_formatter/txt.rb
@@ -4,7 +4,7 @@ module Txt
       extend Base
 
       class << self
-        def call(message, backtrace, options = {}, env = nil, exception = '')
+        def call(message, backtrace, options = {}, env = nil, original_exception = nil)
           message = present(message, env)
 
           result = message.is_a?(Hash) ? ::Grape::Json.dump(message) : message
@@ -12,7 +12,9 @@ def call(message, backtrace, options = {}, env = nil, exception = '')
             result += "\r\n "
             result += backtrace.join("\r\n ")
           end
-          result += "\r\n #{exception}" if (options[:rescue_options] || {})[:exception] && !exception.empty?
+          if (options[:rescue_options] || {})[:original_exception] && original_exception
+            result += "\r\n #{original_exception.inspect}"
+          end
           result
         end
       end
diff --git a/lib/grape/error_formatter/xml.rb b/lib/grape/error_formatter/xml.rb
index e29037ee3..975644c26 100644
--- a/lib/grape/error_formatter/xml.rb
+++ b/lib/grape/error_formatter/xml.rb
@@ -4,14 +4,16 @@ module Xml
       extend Base
 
       class << self
-        def call(message, backtrace, options = {}, env = nil, exception = '')
+        def call(message, backtrace, options = {}, env = nil, original_exception = nil)
           message = present(message, env)
 
           result = message.is_a?(Hash) ? message : { message: message }
           if (options[:rescue_options] || {})[:backtrace] && backtrace && !backtrace.empty?
             result = result.merge(backtrace: backtrace)
           end
-          result = result.merge(exception: exception) if (options[:rescue_options] || {})[:exception] && !exception.empty?
+          if (options[:rescue_options] || {})[:original_exception] && original_exception
+            result = result.merge(original_exception: original_exception.inspect)
+          end
           result.respond_to?(:to_xml) ? result.to_xml(root: :error) : result.to_s
         end
       end
diff --git a/lib/grape/middleware/error.rb b/lib/grape/middleware/error.rb
index 4b6c3184a..dee065dd3 100644
--- a/lib/grape/middleware/error.rb
+++ b/lib/grape/middleware/error.rb
@@ -16,7 +16,7 @@ def default_options
           rescue_subclasses: true, # rescue subclasses of exceptions listed
           rescue_options: {
             backtrace: false, # true to display backtrace, true to let Grape handle Grape::Exceptions
-            exception: false, # true to display exception
+            original_exception: false, # true to display exception
           },
           rescue_handlers: {}, # rescue handler blocks
           base_only_rescue_handlers: {}, # rescue handler blocks rescuing only the base class
@@ -80,13 +80,13 @@ def exec_handler(e, &handler)
         end
       end
 
-      def error!(message, status = options[:default_status], headers = {}, backtrace = [], exception = '')
+      def error!(message, status = options[:default_status], headers = {}, backtrace = [], original_exception = '')
         headers = headers.reverse_merge(Grape::Http::Headers::CONTENT_TYPE => content_type)
-        rack_response(format_message(message, backtrace, exception), status, headers)
+        rack_response(format_message(message, backtrace, original_exception), status, headers)
       end
 
       def handle_error(e)
-        error_response(message: e.message, backtrace: e.backtrace, exception: e.class.name)
+        error_response(message: e.message, backtrace: e.backtrace, original_exception: e)
       end
 
       # TODO: This method is deprecated. Refactor out.
@@ -95,24 +95,24 @@ def error_response(error = {})
         message = error[:message] || options[:default_message]
         headers = { Grape::Http::Headers::CONTENT_TYPE => content_type }
         headers.merge!(error[:headers]) if error[:headers].is_a?(Hash)
-        backtrace = error[:backtrace] || []
-        exception = error.is_a?(Exception) ? error.class.name : error[:exception] || ''
-        rack_response(format_message(message, backtrace, exception), status, headers)
+        backtrace = error[:backtrace] || error[:original_exception] && error[:original_exception].backtrace || []
+        original_exception = error.is_a?(Exception) ? error : error[:original_exception] || nil
+        rack_response(format_message(message, backtrace, original_exception), status, headers)
       end
 
       def rack_response(message, status = options[:default_status], headers = { Grape::Http::Headers::CONTENT_TYPE => content_type })
         Rack::Response.new([message], status, headers).finish
       end
 
-      def format_message(message, backtrace, exception)
+      def format_message(message, backtrace, original_exception = nil)
         format = env[Grape::Env::API_FORMAT] || options[:format]
         formatter = Grape::ErrorFormatter.formatter_for(format, options)
         throw :error,
               status: 406,
               message: "The requested format '#{format}' is not supported.",
               backtrace: backtrace,
-              exception: exception unless formatter
-        formatter.call(message, backtrace, options, env, exception)
+              original_exception: original_exception unless formatter
+        formatter.call(message, backtrace, options, env, original_exception)
       end
 
       private
diff --git a/spec/grape/middleware/exception_spec.rb b/spec/grape/middleware/exception_spec.rb
index fc933558c..5ab8eacc2 100644
--- a/spec/grape/middleware/exception_spec.rb
+++ b/spec/grape/middleware/exception_spec.rb
@@ -162,7 +162,7 @@ def call(_env)
             rescue_all: true,
             format: :custom,
             error_formatters: {
-              custom: lambda do |message, _backtrace, _options, _env, _exception|
+              custom: lambda do |message, _backtrace, _options, _env, _original_exception|
                 { custom_formatter: message }.inspect
               end
             }
@@ -198,11 +198,14 @@ def call(_env)
       it 'is possible to return the backtrace and exception in json format' do
         @app ||= Rack::Builder.app do
           use Spec::Support::EndpointFaker
-          use Grape::Middleware::Error, rescue_all: true, format: :json, rescue_options: { backtrace: true, exception: true }
+          use Grape::Middleware::Error,
+              rescue_all: true,
+              format: :json,
+              rescue_options: { backtrace: true, original_exception: true }
           run ExceptionSpec::ExceptionApp
         end
         get '/'
-        expect(last_response.body).to include('error', 'rain!', 'backtrace', 'exception', 'RuntimeError')
+        expect(last_response.body).to include('error', 'rain!', 'backtrace', 'original_exception', 'RuntimeError')
       end
     end
   end

From 35fcf6f5a7448bb417b47412755e46a90bb446ea Mon Sep 17 00:00:00 2001
From: Daniel Gomes <me@danielcsgomes.com>
Date: Fri, 7 Jul 2017 16:42:35 +0100
Subject: [PATCH 5/8] Code review changes

---
 CHANGELOG.md                            |  3 ++-
 lib/grape/error_formatter/json.rb       |  5 +++--
 lib/grape/error_formatter/txt.rb        |  8 ++++---
 lib/grape/error_formatter/xml.rb        |  5 +++--
 lib/grape/middleware/error.rb           |  2 +-
 lib/grape/middleware/formatter.rb       |  4 ++--
 spec/grape/api_spec.rb                  |  4 ++--
 spec/grape/middleware/exception_spec.rb | 28 ++++++++++++++++++++++++-
 8 files changed, 45 insertions(+), 14 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index bd97427f7..4af97c7fc 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -3,10 +3,11 @@
 #### Features
 
 * Your contribution here.
+* [#1652](https://github.com/ruby-grape/grape/pull/1652): Add the original exception to the error_formatter the original exception - [@dcsg](https://github.com/dcsg).
 
 #### Fixes
 
-* [#1652](https://github.com/ruby-grape/grape/pull/1652): Bubble up to the error_formatter the root exception - [@dcsg](https://github.com/dcsg).
+* [#1652](https://github.com/ruby-grape/grape/pull/1652): Fix missing backtrace that was not being bubble up to the error_formatter - [@dcsg](https://github.com/dcsg).
 
 ### 1.0.0 (7/3/2017)
 
diff --git a/lib/grape/error_formatter/json.rb b/lib/grape/error_formatter/json.rb
index 7525eda06..d3ebff765 100644
--- a/lib/grape/error_formatter/json.rb
+++ b/lib/grape/error_formatter/json.rb
@@ -7,10 +7,11 @@ class << self
         def call(message, backtrace, options = {}, env = nil, original_exception = nil)
           result = wrap_message(present(message, env))
 
-          if (options[:rescue_options] || {})[:backtrace] && backtrace && !backtrace.empty?
+          rescue_options = options[:rescue_options] || {}
+          if rescue_options[:backtrace] && backtrace && !backtrace.empty?
             result = result.merge(backtrace: backtrace)
           end
-          if (options[:rescue_options] || {})[:original_exception] && original_exception
+          if rescue_options[:original_exception] && original_exception
             result = result.merge(original_exception: original_exception.inspect)
           end
           ::Grape::Json.dump(result)
diff --git a/lib/grape/error_formatter/txt.rb b/lib/grape/error_formatter/txt.rb
index 210115e26..b58e03152 100644
--- a/lib/grape/error_formatter/txt.rb
+++ b/lib/grape/error_formatter/txt.rb
@@ -8,11 +8,13 @@ def call(message, backtrace, options = {}, env = nil, original_exception = nil)
           message = present(message, env)
 
           result = message.is_a?(Hash) ? ::Grape::Json.dump(message) : message
-          if (options[:rescue_options] || {})[:backtrace] && backtrace && !backtrace.empty?
-            result += "\r\n "
+          rescue_options = options[:rescue_options] || {}
+          if rescue_options[:backtrace] && backtrace && !backtrace.empty?
+            result += "\r\n backtrace:"
             result += backtrace.join("\r\n ")
           end
-          if (options[:rescue_options] || {})[:original_exception] && original_exception
+          if rescue_options[:original_exception] && original_exception
+            result += "\r\n original exception:"
             result += "\r\n #{original_exception.inspect}"
           end
           result
diff --git a/lib/grape/error_formatter/xml.rb b/lib/grape/error_formatter/xml.rb
index 975644c26..73ebf09c8 100644
--- a/lib/grape/error_formatter/xml.rb
+++ b/lib/grape/error_formatter/xml.rb
@@ -8,10 +8,11 @@ def call(message, backtrace, options = {}, env = nil, original_exception = nil)
           message = present(message, env)
 
           result = message.is_a?(Hash) ? message : { message: message }
-          if (options[:rescue_options] || {})[:backtrace] && backtrace && !backtrace.empty?
+          rescue_options = options[:rescue_options] || {}
+          if rescue_options[:backtrace] && backtrace && !backtrace.empty?
             result = result.merge(backtrace: backtrace)
           end
-          if (options[:rescue_options] || {})[:original_exception] && original_exception
+          if rescue_options[:original_exception] && original_exception
             result = result.merge(original_exception: original_exception.inspect)
           end
           result.respond_to?(:to_xml) ? result.to_xml(root: :error) : result.to_s
diff --git a/lib/grape/middleware/error.rb b/lib/grape/middleware/error.rb
index dee065dd3..3c00786bf 100644
--- a/lib/grape/middleware/error.rb
+++ b/lib/grape/middleware/error.rb
@@ -80,7 +80,7 @@ def exec_handler(e, &handler)
         end
       end
 
-      def error!(message, status = options[:default_status], headers = {}, backtrace = [], original_exception = '')
+      def error!(message, status = options[:default_status], headers = {}, backtrace = [], original_exception = nil)
         headers = headers.reverse_merge(Grape::Http::Headers::CONTENT_TYPE => content_type)
         rack_response(format_message(message, backtrace, original_exception), status, headers)
       end
diff --git a/lib/grape/middleware/formatter.rb b/lib/grape/middleware/formatter.rb
index 2970f83dd..5f8caa50f 100644
--- a/lib/grape/middleware/formatter.rb
+++ b/lib/grape/middleware/formatter.rb
@@ -45,7 +45,7 @@ def build_formatted_response(status, headers, bodies)
           Rack::Response.new(bodymap, status, headers)
         end
       rescue Grape::Exceptions::InvalidFormatter => e
-        throw :error, status: 500, message: e.message, backtrace: e.backtrace, exception: e
+        throw :error, status: 500, message: e.message, backtrace: e.backtrace, original_exception: e
       end
 
       def fetch_formatter(headers, options)
@@ -110,7 +110,7 @@ def read_rack_input(body)
           rescue Grape::Exceptions::Base => e
             raise e
           rescue StandardError => e
-            throw :error, status: 400, message: e.message, backtrace: e.backtrace, exception: e
+            throw :error, status: 400, message: e.message, backtrace: e.backtrace, original_exception: e
           end
         else
           env[Grape::Env::API_REQUEST_BODY] = body
diff --git a/spec/grape/api_spec.rb b/spec/grape/api_spec.rb
index 9cda20500..9b5db5a47 100644
--- a/spec/grape/api_spec.rb
+++ b/spec/grape/api_spec.rb
@@ -1996,7 +1996,7 @@ class ChildError < ParentError; end
       before :each do
         module ApiSpec
           class CustomErrorFormatter
-            def self.call(message, _backtrace, _options, _env, _exception)
+            def self.call(message, _backtrace, _options, _env, _original_exception)
               "message: #{message} @backtrace"
             end
           end
@@ -2018,7 +2018,7 @@ def self.call(message, _backtrace, _options, _env, _exception)
         before :each do
           module ApiSpec
             class CustomErrorFormatter
-              def self.call(message, _backtrace, _option, _env, _exception)
+              def self.call(message, _backtrace, _option, _env, _original_exception)
                 "message: #{message} @backtrace"
               end
             end
diff --git a/spec/grape/middleware/exception_spec.rb b/spec/grape/middleware/exception_spec.rb
index 5ab8eacc2..78494a031 100644
--- a/spec/grape/middleware/exception_spec.rb
+++ b/spec/grape/middleware/exception_spec.rb
@@ -195,7 +195,7 @@ def call(_env)
     end
 
     context 'with rescue_options :backtrace and :exception set to true' do
-      it 'is possible to return the backtrace and exception in json format' do
+      it 'is possible to return the backtrace and the original exception in json format' do
         @app ||= Rack::Builder.app do
           use Spec::Support::EndpointFaker
           use Grape::Middleware::Error,
@@ -207,6 +207,32 @@ def call(_env)
         get '/'
         expect(last_response.body).to include('error', 'rain!', 'backtrace', 'original_exception', 'RuntimeError')
       end
+
+      it 'is possible to return the backtrace and the original exception in xml format' do
+        @app ||= Rack::Builder.app do
+          use Spec::Support::EndpointFaker
+          use Grape::Middleware::Error,
+              rescue_all: true,
+              format: :xml,
+              rescue_options: { backtrace: true, original_exception: true }
+          run ExceptionSpec::ExceptionApp
+        end
+        get '/'
+        expect(last_response.body).to include('error', 'rain!', 'backtrace', 'original-exception', 'RuntimeError')
+      end
+
+      it 'is possible to return the backtrace and the original exception in txt format' do
+        @app ||= Rack::Builder.app do
+          use Spec::Support::EndpointFaker
+          use Grape::Middleware::Error,
+              rescue_all: true,
+              format: :txt,
+              rescue_options: { backtrace: true, original_exception: true }
+          run ExceptionSpec::ExceptionApp
+        end
+        get '/'
+        expect(last_response.body).to include('error', 'rain!', 'backtrace', 'original exception', 'RuntimeError')
+      end
     end
   end
 end

From d9f5e5137b9b3c3b22e4ee5bc9ebd9e8b12ce165 Mon Sep 17 00:00:00 2001
From: Daniel Gomes <me@danielcsgomes.com>
Date: Tue, 11 Jul 2017 00:59:12 +0100
Subject: [PATCH 6/8] add missing test

---
 spec/grape/middleware/formatter_spec.rb | 29 ++++++++++++++++++++++++-
 1 file changed, 28 insertions(+), 1 deletion(-)

diff --git a/spec/grape/middleware/formatter_spec.rb b/spec/grape/middleware/formatter_spec.rb
index c90f6c1f9..87484b4c9 100644
--- a/spec/grape/middleware/formatter_spec.rb
+++ b/spec/grape/middleware/formatter_spec.rb
@@ -1,11 +1,12 @@
 require 'spec_helper'
 
 describe Grape::Middleware::Formatter do
-  subject { Grape::Middleware::Formatter.new(app) }
+  subject { Grape::Middleware::Formatter.new(app, options) }
   before { allow(subject).to receive(:dup).and_return(subject) }
 
   let(:body) { { 'foo' => 'bar' } }
   let(:app) { ->(_env) { [200, {}, [body]] } }
+  let(:options) { {} }
 
   context 'serialization' do
     let(:body) { { 'abc' => 'def' } }
@@ -324,4 +325,30 @@ def self.call(_, _)
       expect(bodies.body.first).to eq({ message: 'invalid' }.to_json)
     end
   end
+
+  context 'custom parser raises exception and rescue options are enabled for backtrace and original_exception' do
+    let(:options) {
+      {
+        rescue_options: { backtrace: true, original_exception: true },
+        parsers: { json: ->(_object, _env) { raise StandardError, 'fail' } }
+      }
+    }
+
+    it 'adds the backtrace and original_exception to the error output' do
+      io = StringIO.new('{invalid}')
+      error = catch(:error) {
+        subject.call(
+          'PATH_INFO' => '/info',
+          'REQUEST_METHOD' => 'POST',
+          'CONTENT_TYPE' => 'application/json',
+          'rack.input' => io,
+          'CONTENT_LENGTH' => io.length
+        )
+      }
+
+      expect(error[:message]).to eq 'fail'
+      expect(error[:backtrace].size).to be >= 1
+      expect(error[:original_exception].class).to eq StandardError
+    end
+  end
 end

From 04762315adcb2bc24c749c41281d468c5966fe67 Mon Sep 17 00:00:00 2001
From: Daniel Gomes <me@danielcsgomes.com>
Date: Tue, 11 Jul 2017 01:17:25 +0100
Subject: [PATCH 7/8] rubocop fixes

---
 .rubocop_todo.yml | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/.rubocop_todo.yml b/.rubocop_todo.yml
index 41b50f3ee..04940c0fe 100644
--- a/.rubocop_todo.yml
+++ b/.rubocop_todo.yml
@@ -1,6 +1,6 @@
 # This configuration was generated by
 # `rubocop --auto-gen-config`
-# on 2017-06-17 22:15:11 +0300 using RuboCop version 0.47.0.
+# on 2017-07-11 00:59:31 +0100 using RuboCop version 0.47.0.
 # The point is for the user to remove these configuration records
 # one by one as the offenses are removed from the code base.
 # Note that changes in the inspected code, or installation of new
@@ -44,6 +44,11 @@ Metrics/ModuleLength:
 Metrics/PerceivedComplexity:
   Max: 14
 
+# Offense count: 2
+Style/BlockDelimiters:
+  Exclude:
+    - 'spec/grape/middleware/formatter_spec.rb'
+
 # Offense count: 2
 Style/IdenticalConditionalBranches:
   Exclude:

From 469b05d2b236cdaaafad902c372cb06b4f374b3a Mon Sep 17 00:00:00 2001
From: Daniel Gomes <me@danielcsgomes.com>
Date: Tue, 11 Jul 2017 01:40:27 +0100
Subject: [PATCH 8/8] trying to fix random test failures

---
 spec/grape/middleware/formatter_spec.rb | 13 +++++--------
 1 file changed, 5 insertions(+), 8 deletions(-)

diff --git a/spec/grape/middleware/formatter_spec.rb b/spec/grape/middleware/formatter_spec.rb
index 87484b4c9..aeab1c4e1 100644
--- a/spec/grape/middleware/formatter_spec.rb
+++ b/spec/grape/middleware/formatter_spec.rb
@@ -1,12 +1,11 @@
 require 'spec_helper'
 
 describe Grape::Middleware::Formatter do
-  subject { Grape::Middleware::Formatter.new(app, options) }
+  subject { Grape::Middleware::Formatter.new(app) }
   before { allow(subject).to receive(:dup).and_return(subject) }
 
   let(:body) { { 'foo' => 'bar' } }
   let(:app) { ->(_env) { [200, {}, [body]] } }
-  let(:options) { {} }
 
   context 'serialization' do
     let(:body) { { 'abc' => 'def' } }
@@ -327,14 +326,12 @@ def self.call(_, _)
   end
 
   context 'custom parser raises exception and rescue options are enabled for backtrace and original_exception' do
-    let(:options) {
-      {
+    it 'adds the backtrace and original_exception to the error output' do
+      subject = Grape::Middleware::Formatter.new(
+        app,
         rescue_options: { backtrace: true, original_exception: true },
         parsers: { json: ->(_object, _env) { raise StandardError, 'fail' } }
-      }
-    }
-
-    it 'adds the backtrace and original_exception to the error output' do
+      )
       io = StringIO.new('{invalid}')
       error = catch(:error) {
         subject.call(