added error handling to cat command

CHANGELOG

@@ -12,6 +12,7 @@
 * added "unindent" helper to make adding help to commands easier
 * local ./.pryrc now loaded after ~/.pryrc if it exists
 * cat --ex N and edit --ex N now can navigate through backtrace, where cat --ex (with no args) moves throuh successive levels of the backtrace automatically with state stored on the exceptino object itself
+* new option Pry.config.exception_window_size determines window size for cat --ex
 
 8/9/2011 version 0.9.5
 

lib/pry/default_commands/shell.rb

@@ -92,8 +92,13 @@ class Pry
           next
         end
 
-        contents, _, _ = read_between_the_lines(file_name, start_line, end_line)
-        contents = syntax_highlight_by_file_type_or_specified(contents, file_name, opts[:type])
+        begin
+          contents, _, _ = read_between_the_lines(file_name, start_line, end_line)
+          contents = syntax_highlight_by_file_type_or_specified(contents, file_name, opts[:type])
+        rescue Errno::ENOENT
+          output.puts "Could not find file: #{file_name}"
+          next
+        end
 
         if opts.l?
           contents = text.with_line_numbers contents, start_line + 1
@@ -115,7 +120,7 @@ class Pry
 
           # header for exceptions
           output.puts "\n#{Pry::Helpers::Text.bold('Exception:')} #{_pry_.last_exception.class}: #{_pry_.last_exception.message}\n--"
-          output.puts "#{Pry::Helpers::Text.bold('From:')} #{ex_file} @ line #{ex_line} @ #{text.bold('level: ')} #{bt_index} of backtrace.\n\n"
+          output.puts "#{Pry::Helpers::Text.bold('From:')} #{ex_file} @ line #{ex_line} @ #{text.bold('level: ')} #{bt_index} of backtrace (of #{_pry_.last_exception.backtrace.size - 1}).\n\n"
         end
 
         set_file_and_dir_locals(file_name)

test/test_default_commands/test_shell.rb

@@ -3,6 +3,12 @@ require 'helper'
 describe "Pry::DefaultCommands::Shell" do
   describe "cat" do
 
+    describe "on receiving a file that does not exist" do
+      it 'should display an error message' do
+        mock_pry("cat supercalifragilicious66").should =~ /Could not find file/
+      end
+    end
+
     # this doesnt work so well on rbx due to differences in backtrace
     # so we currently skip rbx until we figure out a workaround
     describe "with --ex" do