Don't eat my ARGV!

Change the way that OptionParser.parse! is called, so that it doesn't
directly sink its teeth into ARGV.  This necessitated changing the way that
collect_command_line_tasks get the list of command-line arguments to examine
to get tasks and environment variable definitions, but that's a relatively
minor thing.

lib/rake/application.rb

@@ -83,8 +83,8 @@ def run
     def init(app_name='rake')
       standard_exception_handling do
         @name = app_name
-        handle_options
-        collect_command_line_tasks
+        args = handle_options
+        collect_command_line_tasks(args)
       end
     end
 
@@ -616,7 +616,9 @@ def select_trace_output(options, trace_option, value) # :nodoc:
     end
     private :select_trace_output
 
-    # Read and handle the command line options.
+    # Read and handle the command line options.  Returns the command line
+    # arguments that we didn't understand, which should (in theory) be just
+    # task names and env vars.
     def handle_options # :nodoc:
       options.rakelib = ['rakelib']
       options.trace_output = $stderr
@@ -633,7 +635,7 @@ def handle_options # :nodoc:
 
         standard_rake_options.each { |args| opts.on(*args) }
         opts.environment('RAKEOPT')
-      end.parse!
+      end.parse(ARGV)
     end
 
     # Similar to the regular Ruby +require+ command, but will check
@@ -727,9 +729,14 @@ def standard_system_dir #:nodoc:
     # Collect the list of tasks on the command line.  If no tasks are
     # given, return a list containing only the default task.
     # Environmental assignments are processed at this time as well.
-    def collect_command_line_tasks # :nodoc:
+    #
+    # `args` is the list of arguments to peruse to get the list of tasks.
+    # It should be the command line that was given to rake, less any
+    # recognised command-line options, which OptionParser.parse will
+    # have taken care of already.
+    def collect_command_line_tasks(args) # :nodoc:
       @top_level_tasks = []
-      ARGV.each do |arg|
+      args.each do |arg|
         if arg =~ /^(\w+)=(.*)$/m
           ENV[$1] = $2
         else

test/test_rake_application.rb

@@ -370,15 +370,15 @@ def test_building_imported_files_on_demand
     # HACK no assertions
   end
 
-  def test_handle_options_should_strip_options_from_argv
+  def test_handle_options_should_not_strip_options_from_argv
     assert !@app.options.trace
 
     valid_option = '--trace'
     setup_command_line(valid_option)
 
     @app.handle_options
 
-    assert !ARGV.include?(valid_option)
+    assert ARGV.include?(valid_option)
     assert @app.options.trace
   end
 

test/test_rake_application_options.rb

@@ -457,8 +457,8 @@ def @app.exit(*args)
       throw :system_exit, :exit
     end
     @app.instance_eval do
-      handle_options
-      collect_command_line_tasks
+      args = handle_options
+      collect_command_line_tasks(args)
     end
     @tasks = @app.top_level_tasks
     @app.options