Finalizing encoding-aware diff fixes.

* Diff::LCS::Hunk could not properly generate a difference for
  comparison sets that are not US-ASCII-compatible because of the use of
  literal regular expressions and strings. Jon Rowe (JonRowe) found this
  in rspec/rspec-expectations#219 and provided a first pass
  implementation in diff-lcs#15. I've reworked it because of test
  failures in Rubinius when running in Ruby 1.9 mode. This coerces the
  added values to the encoding of the old dataset (as determined by the
  first piece of the old dataset).
  rspec/rspec-expectations#219
  #15
* Adding Travis CI testing for Ruby 2.0.

.travis.yml

@@ -6,8 +6,9 @@ before_script:
 - rake travis:before -t
 language: ruby
 notifications:
-  email: false
+  email: true
 rvm:
+  - 2.0.0
   - 1.9.3
   - 1.9.2
   - ruby-head

Contributing.rdoc

@@ -61,3 +61,4 @@ Thanks to everyone else who has contributed to Diff::LCS:
 * Kenichi Kamiya
 * Michael Granger
 * Vít Ondruch
+* Jon Rowe

History.rdoc

@@ -1,3 +1,17 @@
+== 1.2.2 / 2013-03-30
+
+* Bugs Fixed:
+  * Diff::LCS::Hunk could not properly generate a difference for comparison
+    sets that are not US-ASCII-compatible because of the use of literal regular
+    expressions and strings. Jon Rowe (JonRowe) found this in
+    rspec/rspec-expectations#219 and provided a first pass implementation in
+    diff-lcs#15. I've reworked it because of test failures in Rubinius when
+    running in Ruby 1.9 mode. This coerces the added values to the encoding of
+    the old dataset (as determined by the first piece of the old dataset).
+    https://github.com/rspec/rspec-expectations/issues/219
+    https://github.com/halostatue/diff-lcs/pull/15
+* Adding Travis CI testing for Ruby 2.0.
+
 == 1.2.1 / 2013-02-09
 
 * Bugs Fixed:

README.rdoc

@@ -11,9 +11,9 @@ Diff::LCS computes the difference between two Enumerable sequences using the
 McIlroy-Hunt longest common subsequence (LCS) algorithm. It includes utilities
 to create a simple HTML diff output format and a standard diff-like tool.
 
-This is release 1.2.1, restoring the public API to what existed in Diff::LCS
-1.1.x. Everyone is strongly encouraged to upgrade to this version as it fixes
-all known outstanding issues.
+This is release 1.2.2, fixing a bug that prevented comparison of values that
+are not US-ASCII-compatible. Thanks to Jon Rowe for finding and providing most
+of the work behind this issue. This is a recommended release.
 
 == Synopsis
 

lib/diff/lcs.rb

@@ -1,7 +1,7 @@
 # -*- ruby encoding: utf-8 -*-
 
 module Diff; end unless defined? Diff
-# = Diff::LCS 1.2.1
+# = Diff::LCS 1.2.2
 #
 # Computes "intelligent" differences between two sequenced Enumerables. This
 # is an implementation of the McIlroy-Hunt "diff" algorithm for Enumerable
@@ -129,7 +129,7 @@ module Diff; end unless defined? Diff
 # Common Subsequences</em>, CACM, vol.20, no.5, pp.350-353, May
 # 1977, with a few minor improvements to improve the speed."
 module Diff::LCS
-  VERSION = '1.2.1'
+  VERSION = '1.2.2'
 end
 
 require 'diff/lcs/callbacks'

lib/diff/lcs/hunk.rb

@@ -11,7 +11,9 @@ class Diff::LCS::Hunk
   def initialize(data_old, data_new, piece, flag_context, file_length_difference)
     # At first, a hunk will have just one Block in it
     @blocks = [ Diff::LCS::Block.new(piece) ]
-    @preferred_data_encoding = data_old[0].encoding if String.method_defined?(:encoding)
+    if String.method_defined?(:encoding)
+      @preferred_data_encoding = data_old[0].encoding
+    end
     @data_old = data_old
     @data_new = data_new
 
@@ -146,17 +148,17 @@ def unified_diff
     # file -- don't take removed items into account.
     lo, hi, num_added, num_removed = @start_old, @end_old, 0, 0
 
-    outlist = @data_old[lo .. hi].collect { |e| match_encoding_gsub(e,'^', ' ') }
+    outlist = @data_old[lo .. hi].map { |e| e.insert(0, encode(' ')) }
 
     @blocks.each do |block|
       block.remove.each do |item|
-        op = item.action.to_s # -
+        op     = item.action.to_s # -
         offset = item.position - lo + num_added
-        match_encoding_gsub!(outlist[offset],'^ ', op.to_s)
+        outlist[offset][0, 1] = encode(op)
         num_removed += 1
       end
       block.insert.each do |item|
-        op = item.action.to_s # +
+        op     = item.action.to_s # +
         offset = item.position - @start_new + num_removed
         outlist[offset, 0] = encode(op) + @data_new[item.position]
         num_added += 1
@@ -177,10 +179,11 @@ def context_diff
     lo, hi = @start_old, @end_old
     removes = @blocks.select { |e| not e.remove.empty? }
     if removes
-      outlist = @data_old[lo .. hi].collect { |e| match_encoding_gsub(e,'^', ' ') }
+      outlist = @data_old[lo .. hi].map { |e| e.insert(0, encode(' ')) }
+
       removes.each do |block|
         block.remove.each do |item|
-          match_encoding_gsub!( outlist[item.position - lo], '^ ') { block.op } # - or !
+          outlist[item.position - lo][0, 1] = encode(block.op) # - or !
         end
       end
       s << outlist.join("\n")
@@ -190,10 +193,10 @@ def context_diff
     lo, hi = @start_new, @end_new
     inserts = @blocks.select { |e| not e.insert.empty? }
     if inserts
-      outlist = @data_new[lo .. hi].collect { |e| match_encoding_gsub(e,'^', '  ') }
+      outlist = @data_new[lo .. hi].collect { |e| e.insert(0, encode(' ')) }
       inserts.each do |block|
         block.insert.each do |item|
-          match_encoding_gsub!( outlist[item.position - lo], '^ ') { block.op } # + or !
+          outlist[item.position - lo][0, 1] = encode(block.op) # + or !
         end
       end
       s << outlist.join("\n")
@@ -209,7 +212,7 @@ def ed_diff(format)
     if format == :reverse_ed
       s = encode("#{op_act[@blocks[0].op]}#{context_range(:old)}\n")
     else
-      s = encode("#{match_encoding_gsub(context_range(:old), ',', ' ')}#{op_act[@blocks[0].op]}\n")
+      s = encode("#{context_range(:old, ' ')}#{op_act[@blocks[0].op]}\n")
     end
 
     unless @blocks[0].insert.empty?
@@ -222,15 +225,15 @@ def ed_diff(format)
 
   # Generate a range of item numbers to print. Only print 1 number if the
   # range has only one item in it. Otherwise, it's 'start,end'
-  def context_range(mode)
+  def context_range(mode, op = ',')
     case mode
     when :old
       s, e = (@start_old + 1), (@end_old + 1)
     when :new
       s, e = (@start_new + 1), (@end_new + 1)
     end
 
-    (s < e) ? "#{s},#{e}" : "#{e}"
+    (s < e) ? "#{s}#{op}#{e}" : "#{e}"
   end
   private :context_range
 
@@ -252,33 +255,22 @@ def unified_range(mode)
   private :unified_range
 
   if String.method_defined?(:encoding)
-    def encode(literal)
-      literal.encode @preferred_data_encoding
+    def encode(literal, target_encoding = @preferred_data_encoding)
+      literal.encode target_encoding
     end
 
-    def encode_to(string, args)
+    def encode_as(string, *args)
       args.map { |arg| arg.encode(string.encoding) }
     end
   else
-    def encode(literal)
+    def encode(literal, target_encoding = nil)
       literal
     end
-    def encode_to(string, args)
+    def encode_as(string, *args)
       args
     end
   end
 
   private :encode
-  private :encode_to
-
-  def match_encoding_gsub(string, *args, &block)
-    string.gsub(*encode_to(string,args), &block)
-  end
-  private :match_encoding_gsub
-
-  def match_encoding_gsub!(string, *args, &block)
-    string.gsub!(*encode_to(string,args), &block)
-  end
-  private :match_encoding_gsub!
-
+  private :encode_as
 end

spec/hunk_spec.rb

@@ -2,38 +2,42 @@
 
 require 'spec_helper'
 
-describe "Diff::LCS::Hunk" do
+def h(v)
+  v.to_s.bytes.to_a.map { |e| "%02x" % e }.join
+end
 
+describe "Diff::LCS::Hunk" do
   if String.method_defined?(:encoding)
 
     let(:old_data) { ["Tu avec carté {count} itém has".encode('UTF-16LE')] }
     let(:new_data) { ["Tu avec carte {count} item has".encode('UTF-16LE')] }
-    let(:peices)   { Diff::LCS.diff old_data, new_data }
-    let(:hunk)     { Diff::LCS::Hunk.new(old_data, new_data, peices[0], 3, 0) }
+    let(:pieces)   { Diff::LCS.diff old_data, new_data }
+    let(:hunk)     { Diff::LCS::Hunk.new(old_data, new_data, pieces[0], 3, 0) }
 
-    it 'should be able to produce a unified diff from the two peices' do
+    it 'should be able to produce a unified diff from the two pieces' do
       expected =
 (<<-EOD.encode('UTF-16LE').chomp)
 @@ -1,2 +1,2 @@
-Tu avec carté {count} itém has
+-Tu avec carté {count} itém has
 +Tu avec carte {count} item has
 EOD
       expect(hunk.diff(:unified).to_s == expected).to eql true
     end
 
-    it 'should be able to produce a context diff from the two peices' do
+    it 'should be able to produce a context diff from the two pieces' do
       expected =
 (<<-EOD.encode('UTF-16LE').chomp)
 ***************
 *** 1,2 ****
-Tu avec carté {count} itém has
+!Tu avec carté {count} itém has
 --- 1,2 ----
-Tu avec carte {count} item has
+!Tu avec carte {count} item has
 EOD
+
       expect(hunk.diff(:context).to_s == expected).to eql true
     end
 
-    it 'should be able to produce an old diff from the two peices' do
+    it 'should be able to produce an old diff from the two pieces' do
       expected =
 (<<-EOD.encode('UTF-16LE').chomp)
 1,2c1,2
@@ -45,7 +49,7 @@
       expect(hunk.diff(:old).to_s == expected).to eql true
     end
 
-    it 'should be able to produce a reverse ed diff from the two peices' do
+    it 'should be able to produce a reverse ed diff from the two pieces' do
       expected =
 (<<-EOD.encode('UTF-16LE').chomp)
 c1,2