Improve performance for many unresolved includes/extends

Potential fix for ruby#1126

lib/rdoc/mixin.rb

@@ -18,6 +18,7 @@ def initialize(name, comment)
  @name = name
  self.comment = comment
  @module = nil # cache for module if found
+ @module_lookup_failed = false
  end
 
  ##
@@ -64,16 +65,10 @@ def inspect # :nodoc:
  # - if not found, look into the children of included modules,
  # in reverse inclusion order;
  # - if still not found, go up the hierarchy of names.
- #
- # This method has <code>O(n!)</code> behavior when the module calling
- # include is referencing nonexistent modules. Avoid calling #module until
- # after all the files are parsed. This behavior is due to ruby's constant
- # lookup behavior.
- #
- # As of the beginning of October, 2011, no gem includes nonexistent modules.
 
  def module
  return @module if @module
+ return @name if @module_lookup_failed
 
  # search the current context
  return @name unless parent
@@ -101,6 +96,7 @@ def module
  up = up.parent
  end
 
+ @module_lookup_failed = true
  @name
  end
 

test/rdoc/test_rdoc_context.rb

@@ -409,13 +409,26 @@ def test_add_to_done_documenting
  refute_includes arr, incl
  end
 
- def bench_add_include
- cm = RDoc::ClassModule.new 'Klass'
+ def test_bench_add_include
+ assert_linear_performance (1..25) do |count|
+ cm = RDoc::ClassModule.new 'Klass'
+ count.times do |i|
+ cm.add_include RDoc::Include.new("N::M#{i}", nil)
+ end
+ end
+ end
+
+ def test_bench_include_module_resolution
+ assert_linear_performance (1..25) do |count|
+ cm = RDoc::ClassModule.new 'Klass'
+ cm.store = RDoc::Store.new
 
- assert_performance_linear 0.5 do |count|
  count.times do |i|
  cm.add_include RDoc::Include.new("N::M#{i}", nil)
  end
+ last_include = RDoc::Include.new("N::M#{count + 1}", nil)
+ cm.add_include(last_include)
+ last_include.module
  end
  end