Fix rescue_from ValidationErrors exception (#2480)

* Fix rescue_from ValidationErrors exception

* Update CHANGELOG

Author: numbata

CHANGELOG.md

@@ -9,6 +9,7 @@
 
 * [#2471](https://github.com/ruby-grape/grape/pull/2471): Fix absence of original_exception and/or backtrace even if passed in error! - [@numbata](https://github.com/numbata).
 * [#2478](https://github.com/ruby-grape/grape/pull/2478): Fix rescue_from with invalid response - [@ericproulx](https://github.com/ericproulx).
+* [#2480](https://github.com/ruby-grape/grape/pull/2480): Fix rescue_from ValidationErrors exception - [@numbata](https://github.com/numbata).
 * Your contribution here.
 
 ### 2.1.3 (2024-07-13)

lib/grape/error_formatter/json.rb

@@ -9,17 +9,18 @@ class << self
         def call(message, backtrace, options = {}, env = nil, original_exception = nil)
           result = wrap_message(present(message, env))
 
-          rescue_options = options[:rescue_options] || {}
-          result = result.merge(backtrace: backtrace) if rescue_options[:backtrace] && backtrace && !backtrace.empty?
-          result = result.merge(original_exception: original_exception.inspect) if rescue_options[:original_exception] && original_exception
+          result = merge_rescue_options(result, backtrace, options, original_exception) if result.is_a?(Hash)
+
           ::Grape::Json.dump(result)
         end
 
         private
 
         def wrap_message(message)
-          if message.is_a?(Exceptions::ValidationErrors) || message.is_a?(Hash)
+          if message.is_a?(Hash)
             message
+          elsif message.is_a?(Exceptions::ValidationErrors)
+            message.as_json
           else
             { error: ensure_utf8(message) }
           end
@@ -30,6 +31,14 @@ def ensure_utf8(message)
 
           message.encode('UTF-8', invalid: :replace, undef: :replace)
         end
+
+        def merge_rescue_options(result, backtrace, options, original_exception)
+          rescue_options = options[:rescue_options] || {}
+          result = result.merge(backtrace: backtrace) if rescue_options[:backtrace] && backtrace && !backtrace.empty?
+          result = result.merge(original_exception: original_exception.inspect) if rescue_options[:original_exception] && original_exception
+
+          result
+        end
       end
     end
   end

spec/grape/api_spec.rb

@@ -2743,6 +2743,57 @@ def self.call(message, _backtrace, _options, _env, _original_exception)
         it { is_expected.to have_key('backtrace') & have_key('original-exception') }
       end
     end
+
+    context 'when rescue validation errors include backtrace and original exception' do
+      let(:app) do
+        response_type = response_format
+
+        Class.new(Grape::API) do
+          format response_type
+
+          rescue_from Grape::Exceptions::ValidationErrors, backtrace: true, original_exception: true do |e|
+            error!(e, 418, {}, e.backtrace, e)
+          end
+
+          params do
+            requires :weather
+          end
+          get '/forecast' do
+            'sunny'
+          end
+        end
+      end
+
+      before do
+        get '/forecast'
+      end
+
+      context 'with json response type format' do
+        subject { JSON.parse(last_response.body) }
+
+        let(:response_format) { :json }
+
+        it 'does not include backtrace or original exception' do
+          expect(subject).to match([{ 'messages' => ['is missing'], 'params' => ['weather'] }])
+        end
+      end
+
+      context 'with txt response type format' do
+        subject { last_response.body }
+
+        let(:response_format) { :txt }
+
+        it { is_expected.to include('backtrace', 'original exception') }
+      end
+
+      context 'with xml response type format' do
+        subject { Grape::Xml.parse(last_response.body)['error'] }
+
+        let(:response_format) { :xml }
+
+        it { is_expected.to have_key('backtrace') & have_key('original-exception') }
+      end
+    end
   end
 
   describe '.content_type' do