edit: ensure 'edit --ex' always edits the exception

There was a bug where if 'edit --ex' was invoked in a patched method context
it would instead to the equivalent of 'edit --method' (patching the current method
rather than the exception)

lib/pry/commands/edit.rb

@@ -69,8 +69,12 @@ class Pry
       end
     end
 
+    def file_based_exception?
+      opts.present?(:ex) && !opts.present?(:patch)
+    end
+
     def runtime_patch?
-      opts.present?(:patch) || pry_method?(code_object)
+       !file_based_exception? && (opts.present?(:patch) || pry_method?(code_object))
     end
 
     def apply_runtime_patch

spec/commands/edit_spec.rb

@@ -142,6 +142,7 @@ describe "edit" do
         def last_exception=(exception)
           @pry.last_exception = exception
         end
+        def last_exception; @pry.last_exception; end
       end
     end
 
@@ -177,6 +178,27 @@ describe "edit" do
         FOO.should == 'BAR'
       end
 
+      # regression test (this used to edit the current method instead
+      # of the exception)
+      it 'edits the exception even when in a patched method context' do
+        source_location = nil
+        Pry.config.editor = lambda {|file, line|
+          source_location = [file, line]
+          nil
+        }
+
+        Pad.le = @t.last_exception
+        redirect_pry_io(InputTester.new("def broken_method", "binding.pry", "end",
+                                        "broken_method",
+                                        "_pry_.last_exception = Pad.le",
+                                        "edit --ex -n", "exit-all", "exit-all")) do
+          Object.new.pry
+        end
+
+        source_location.should == [@path, 3]
+        Pad.clear
+      end
+
       it "should not reload the file if -n is passed" do
         Pry.config.editor = lambda {|file, line|
           File.open(file, 'w'){|f| f << "FOO2 = 'BAZ'" }