system is now determined by a proc, Pry.config.system

lib/pry.rb

@@ -114,6 +114,11 @@ class Pry
                 end,
                ]
 
+  DEFAULT_SYSTEM = proc do |cmd|
+    if !system(cmd)
+      output.puts "Error: there was a problem executing system command: #{cmd}"
+    end
+  end
 
   # As a REPL, we often want to catch any unexpected exceptions that may have
   # been raised; however we don't want to go overboard and prevent the user

lib/pry/config.rb

@@ -118,6 +118,10 @@ class Pry
     # @return [Proc] The proc that manages ^D presses in the REPL.
     #   The proc is passed the current eval_string and the current pry instance.
     attr_accessor :control_d_handler
+
+    # @return [Proc] The proc that runs system commands
+    #   The proc is passed the command string to eval
+    attr_accessor :system
   end
 end
 

lib/pry/default_commands/shell.rb

@@ -11,11 +11,8 @@ class Pry
           rescue Errno::ENOENT
             output.puts "No such directory: #{dest}"
           end
-
         else
-          if !system(cmd)
-            output.puts "Error: there was a problem executing system command: #{cmd}"
-          end
+          Pry.config.system.call(cmd)
         end
       end
 

lib/pry/helpers/command_helpers.rb

@@ -389,10 +389,13 @@ class Pry
             pid = Spoon.spawnp(*editor_invocation.split)
             Process.waitpid(pid)
           rescue FFI::NotFoundError
-            run ".#{editor_invocation}"
+            system(editor_invocation)
           end
         else
-          run ".#{editor_invocation}"
+          # Note we dont want to use Pry.config.system here as that
+          # may be invoked non-interactively (i.e via Open4), whereas we want to
+          # ensure the editor is always interactive
+          system(editor_invocation)
         end
       end
 

lib/pry/pry_class.rb

@@ -51,7 +51,7 @@ class Pry
     def_delegators :@plugin_manager, :plugins, :load_plugins, :locate_plugins
 
     delegate_accessors :@config, :input, :output, :commands, :prompt, :print, :exception_handler,
-      :hooks, :color, :pager, :editor, :memory_size, :input_stack
+      :hooks, :color, :pager, :editor, :memory_size, :input_stack, :system
   end
 
   # Load the rc files given in the `Pry::RC_FILES` array.
@@ -186,6 +186,7 @@ class Pry
     config.input_stack = []
     config.color = true
     config.pager = true
+    config.system = DEFAULT_SYSTEM
     config.editor = default_editor_for_platform
     config.should_load_rc = true
     config.disable_auto_reload = false