Unwrap last exception when setting _ex_

lib/pry/helpers/base_helpers.rb

@@ -98,6 +98,10 @@ class Pry
         mri? && RUBY_VERSION =~ /2.0/
       end
 
+      def mri_21?
+        mri? && RUBY_VERSION =~ /2.1/
+      end
+
       # Send the given text through the best available pager (if Pry.pager is
       # enabled). Infers where to send the output if used as a mixin.
       def stagger_output(text, out = nil)

lib/pry/last_exception.rb

@@ -1,3 +1,5 @@
+# LastException is a proxy used to add functionality to the `last_exception`
+# attribute of Pry instances.
 class Pry::LastException < BasicObject
   attr_reader :file, :line
   attr_accessor :bt_index
@@ -16,12 +18,12 @@ class Pry::LastException < BasicObject
     end
   end
 
-  def respond_to_missing?(name, boolean=false)
+  def respond_to_missing?(name, include_private = false)
     @e.respond_to?(name)
   end
 
-  def pry?
-    true
+  def wrapped_exception
+    @e
   end
 
   def bt_source_location_for(index)

lib/pry/pry_instance.rb

@@ -183,7 +183,7 @@ class Pry
     { _in_: input_array,
       _out_: output_array,
       _pry_: self,
-      _ex_: last_exception,
+      _ex_: last_exception && last_exception.wrapped_exception,
       _file_: last_file,
       _dir_: last_dir,
       _: proc { last_result },

spec/pry_spec.rb

@@ -75,7 +75,7 @@ describe Pry do
 
     it "returns an instance of Pry::LastException" do
       @pry.last_exception = @e
-      should.satisfy { @pry.last_exception.pry? == true }
+      @pry.last_exception.wrapped_exception.should == @e
     end
 
     it "returns a frozen exception" do

spec/sticky_locals_spec.rb

@@ -21,9 +21,34 @@ describe "Sticky locals (_file_ and friends)" do
     end
   end
 
-  # Using mock_pry here until we figure out exception handling
-  it 'locals should keep value after cd-ing (_ex_)' do
-    mock_pry("error blah;", "$x = _ex_;", "cd 0", "_ex_ == $x").should =~ /true/
+  describe '_ex_' do
+    it 'returns the last exception without wrapping it in a LastException' do
+      ReplTester.start do
+        input  'raise "halp"'
+
+        input  '_ex_.message == "halp"'
+        output '=> true'
+
+        if Pry::Helpers::BaseHelpers.mri_20? || Pry::Helpers::BaseHelpers.mri_21?
+          input  'Kernel.instance_method(:class).bind(_ex_).call'
+          output '=> RuntimeError'
+        end
+
+        input  '_ex_.wrapped_exception'
+        output /NoMethodError/
+      end
+    end
+
+    it 'keeps its value after cd-ing' do
+      ReplTester.start do
+        input  'error blah'
+        input  '$x = _ex_'
+        input  'cd 0'
+
+        input  '_ex_ == $x'
+        output '=> true'
+      end
+    end
   end
 
   it 'locals should keep value after cd-ing (_file_ and _dir_)' do