Merge pull request #115 from gsamokovarov/follow-original-exception

Show proper binding when raising an error in a template

Author: gsamokovarov

lib/web_console/extensions.rb

@@ -0,0 +1,19 @@
+ActionDispatch::DebugExceptions.class_eval do
+  def render_exception_with_web_console(env, exception)
+    render_exception_without_web_console(env, exception).tap do
+      error = ActionDispatch::ExceptionWrapper.new(env, exception).exception
+
+      # Get the original exception if ExceptionWrapper decides to follow it.
+      env['web_console.exception'] = error
+
+      # ActionView::Template::Error bypass ExceptionWrapper original
+      # exception following. The backtrace in the view is generated from
+      # reaching out to original_exception in the view.
+      if error.is_a?(ActionView::Template::Error)
+        env['web_console.exception'] = error.original_exception
+      end
+    end
+  end
+
+  alias_method_chain :render_exception, :web_console
+end

lib/web_console/railtie.rb

@@ -6,18 +6,7 @@ class Railtie < ::Rails::Railtie
     config.web_console.whitelisted_ips = %w( 127.0.0.1 ::1 )
 
     initializer 'web_console.initialize' do
-      ActionDispatch::DebugExceptions.class_eval do
-        def render_exception_with_web_console(env, exception)
-          render_exception_without_web_console(env, exception).tap do
-            wrapper = ActionDispatch::ExceptionWrapper.new(env, exception)
-
-            # Get the original exception if ExceptionWrapper decides to follow it.
-            env['web_console.exception'] = wrapper.exception
-          end
-        end
-
-        alias_method_chain :render_exception, :web_console
-      end
+      require 'web_console/extensions'
 
       ActiveSupport.on_load(:action_view) do
         ActionView::Base.send(:include, Helper)

test/dummy/app/controllers/helper_error_controller.rb

@@ -0,0 +1,4 @@
+class HelperErrorController < ApplicationController
+  def index
+  end
+end

test/dummy/app/views/helper_error/index.html.erb

@@ -0,0 +1,2 @@
+<% @ok = 42 %>
+<% raise %>

test/dummy/config/routes.rb

@@ -4,6 +4,7 @@
   get :exception_test, to: "exception_test#index"
   get :xhr_test, to: "exception_test#xhr"
   get :helper_test, to: "helper_test#index"
+  get :helper_error, to: "helper_error#index"
   get :controller_helper_test, to: "controller_helper_test#index"
 
   namespace :tests do

test/web_console/extensions_test.rb

@@ -0,0 +1,28 @@
+require 'test_helper'
+require 'web_console/extensions'
+
+module ActionDispatch
+  class DebugExceptionsTest < ActionDispatch::IntegrationTest
+    class Application
+      def call(env)
+        ActionView::Base.new.render(inline: '<% @ivar = 42 %> <%= nil.raise %></h1')
+      end
+    end
+
+    setup do
+      Request.stubs(:whitelisted_ips).returns(IPAddr.new('0.0.0.0/0'))
+
+      @app = DebugExceptions.new(Application.new)
+    end
+
+    test "follows ActionView::Template::Error original error in env['web_console.exception']" do
+      get "/", {}, {
+        'action_dispatch.show_detailed_exceptions' => true,
+        'action_dispatch.show_exceptions' => true,
+        'action_dispatch.logger' => Logger.new(StringIO.new)
+      }
+
+      assert_equal 42, request.env['web_console.exception'].bindings.first.eval('@ivar')
+    end
+  end
+end