# This is a combination of 9 commits.

# This is the 1st commit message:

Fix improperly placed chunks

Resolve #65

- Also add even more tests for checking `ldiff` results against `diff` results.
- Fix issues with diff/ldiff output highlighted by the above tests.
- Add a parameter to indicate that the hunk being processed is the _last_ hunk;
  this results in correct counting of the hunk size.
- The misplaced chunks were happening because of an improper `.abs` on
  `#diff_size`, when the `.abs` needed to be on the finding of the maximum diff
  size.

# This is the commit message #2:

Ooops. Debugger

# This is the commit message #3:

Restore missing test

- Fix some more format issues raised by the missing test.
- Start fixing Rubocop formatting.

# This is the commit message #4:

Last RuboCop fixes

# This is the commit message #5:

Finalize diff-lcs 1.4

# This is the commit message #6:

Fix #44

The problem here was the precedence of `or` vs `||`. Switching to `||` resulted
in the expected behaviour.

# This is the commit message #7:

Resolve #43

# This is the commit message #8:

Typo

# This is the commit message #9:

Resolve #35 with a comment

.rubocop.yml

@@ -7,7 +7,7 @@ AllCops:
     - diff-lcs.gemspec
     - research/**/*
 
-Layout/AlignParameters:
+Layout/ParameterAlignment:
   EnforcedStyle: with_fixed_indentation
 
 Layout/DotPosition:
@@ -20,7 +20,7 @@ Layout/ExtraSpacing:
 Layout/MultilineMethodCallIndentation:
   EnforcedStyle: indented
 
-Metrics/LineLength:
+Layout/LineLength:
   Max: 110
 
 Naming/FileName:
@@ -30,17 +30,15 @@ Naming/FileName:
 Naming/MemoizedInstanceVariableName:
   Exclude: []
 
-Naming/UncommunicativeMethodParamName:
+Naming/MethodParameterName:
   Exclude:
     - lib/diff/lcs/internals.rb
+    - lib/diff/lcs/hunk.rb
     - spec/spec_helper.rb
 
 Naming/VariableNumber:
   Exclude: []
 
-Performance/Caller:
-  Exclude: []
-
 Security/MarshalLoad:
   Exclude: []
 
@@ -91,7 +89,7 @@ Style/RescueStandardError:
 Style/SignalException:
   EnforcedStyle: semantic
 
-Layout/IndentHeredoc: { Enabled: false }
+Layout/HeredocIndentation: { Enabled: false }
 Metrics/AbcSize: { Enabled: false }
 Metrics/BlockLength: { Enabled: false }
 Metrics/BlockNesting: { Enabled: false }
@@ -119,3 +117,17 @@ Style/SpecialGlobalVars: { Enabled: false }
 Style/SymbolArray: { Enabled: false }
 Style/SymbolProc: { Enabled: false }
 Style/WordArray: { Enabled: false }
+
+Layout/EmptyLinesAroundAttributeAccessor: { Enabled: true }
+Layout/SpaceAroundMethodCallOperator: { Enabled: true }
+Lint/DeprecatedOpenSSLConstant: { Enabled: true }
+Lint/MixedRegexpCaptureTypes: { Enabled: true }
+Lint/RaiseException: { Enabled: true }
+Lint/StructNewOverride: { Enabled: true }
+Style/ExponentialNotation: { Enabled: true }
+Style/HashEachMethods: { Enabled: true }
+Style/HashTransformKeys: { Enabled: true }
+Style/HashTransformValues: { Enabled: true }
+Style/RedundantRegexpCharacterClass: { Enabled: true }
+Style/RedundantRegexpEscape: { Enabled: true }
+Style/SlicingWithRange: { Enabled: true }

Gemfile

@@ -6,14 +6,15 @@
 source 'https://rubygems.org/'
 
 if RUBY_VERSION < '1.9'
+  gem 'hoe', '~> 3.20'
   gem 'rake', '< 11'
   gem 'rdoc', '< 4'
-  gem 'hoe', '~> 3.20'
 
   gem 'ruby-debug'
 elsif RUBY_VERSION >= '2.0'
   if RUBY_ENGINE == 'ruby'
     gem 'simplecov', '~> 0.18'
+
     gem 'byebug'
   end
 end

History.md

@@ -1,5 +1,15 @@
 # History
 
+## 1.4.4 / 2020-07-01
+
+- Fixed an issue reported by Jun Aruga in the Diff::LCS::Ldiff binary text
+  detection. [#44][]
+- Fixed a theoretical issue reported by Jun Aruga in Diff::LCS::Hunk to raise
+  a more useful exception. [#43][]
+- Added documentation that should address custom object issues as reported in
+  [#35][].
+- Fixed more diff errors, in part reported in [#65][].
+
 ## 1.4.3 / 2020-06-29
 
 - Fixed several issues with the 1.4 on Rubies older than 2.0. Some of this was
@@ -263,8 +273,11 @@
 [#29]: https://github.com/halostatue/diff-lcs/pull/29
 [#33]: https://github.com/halostatue/diff-lcs/issues/33
 [#34]: https://github.com/halostatue/diff-lcs/pull/34
+[#35]: https://github.com/halostatue/diff-lcs/issues/35
 [#36]: https://github.com/halostatue/diff-lcs/pull/36
 [#38]: https://github.com/halostatue/diff-lcs/issues/38
+[#43]: https://github.com/halostatue/diff-lcs/issues/43
+[#44]: https://github.com/halostatue/diff-lcs/issues/44
 [#47]: https://github.com/halostatue/diff-lcs/pull/47
 [#48]: https://github.com/halostatue/diff-lcs/issues/48
 [#49]: https://github.com/halostatue/diff-lcs/pull/49
@@ -276,3 +289,4 @@
 [#60]: https://github.com/halostatue/diff-lcs/issues/60
 [#61]: https://github.com/halostatue/diff-lcs/pull/61
 [#63]: https://github.com/halostatue/diff-lcs/issues/63
+[#65]: https://github.com/halostatue/diff-lcs/issues/65

Rakefile

@@ -10,18 +10,19 @@ Hoe.plugin :gemspec2
 Hoe.plugin :git
 
 if RUBY_VERSION < '1.9'
-  class Array
+  class Array #:nodoc:
     def to_h
-      Hash[*self.flatten(1)]
+      Hash[*flatten(1)]
     end
   end
 
-  class Gem::Specification
-    def metadata=(*)
-    end
+  class Gem::Specification #:nodoc:
+    def metadata=(*); end
+
+    def default_value(*); end
   end
 
-  class Object
+  class Object #:nodoc:
     def caller_locations(*)
       []
     end
@@ -55,3 +56,19 @@ if RUBY_VERSION >= '2.0' && RUBY_ENGINE == 'ruby'
     end
   end
 end
+
+task :ruby18 do
+  puts <<-MESSAGE
+You are starting a barebones Ruby 1.8 docker environment. You will need to
+do the following:
+
+- mv Gemfile.lock{,.v2}
+- gem install bundler --version 1.17.2 --no-ri --no-rdoc
+- ruby -S bundle
+- rake
+
+Don't forget to restore your Gemfile.lock after testing.
+
+  MESSAGE
+  sh "docker run -it --rm -v #{Dir.pwd}:/root/diff-lcs bellbind/docker-ruby18-rails2 bash -l"
+end

diff-lcs.gemspec

@@ -1,16 +1,16 @@
 # -*- encoding: utf-8 -*-
-# stub: diff-lcs 1.4.3 ruby lib
+# stub: diff-lcs 1.4.4 ruby lib
 
 Gem::Specification.new do |s|
   s.name = "diff-lcs".freeze
-  s.version = "1.4.3"
+  s.version = "1.4.4"
 
   s.required_rubygems_version = Gem::Requirement.new(">= 0".freeze) if s.respond_to? :required_rubygems_version=
   s.metadata = { "bug_tracker_uri" => "https://github.com/halostatue/diff-lcs/issues", "homepage_uri" => "https://github.com/halostatue/diff-lcs", "source_code_uri" => "https://github.com/halostatue/diff-lcs" } if s.respond_to? :metadata=
   s.require_paths = ["lib".freeze]
   s.authors = ["Austin Ziegler".freeze]
-  s.date = "2020-06-29"
-  s.description = "Diff::LCS computes the difference between two Enumerable sequences using the\nMcIlroy-Hunt longest common subsequence (LCS) algorithm. It includes utilities\nto create a simple HTML diff output format and a standard diff-like tool.\n\nThis is release 1.4, providing a simple extension that allows for\nDiff::LCS::Change objects to be treated implicitly as arrays. Ruby versions\nbelow 2.5 are soft-deprecated.\n\nThis means that older versions are no longer part of the CI test suite. If any\nchanges have been introduced that break those versions, bug reports and patches\nwill be accepted, but it will be up to the reporter to verify any fixes prior\nto release. A future release will completely break compatibility.".freeze
+  s.date = "2020-07-01"
+  s.description = "Diff::LCS computes the difference between two Enumerable sequences using the\nMcIlroy-Hunt longest common subsequence (LCS) algorithm. It includes utilities\nto create a simple HTML diff output format and a standard diff-like tool.\n\nThis is release 1.4.3, providing a simple extension that allows for\nDiff::LCS::Change objects to be treated implicitly as arrays and fixes a\nnumber of formatting issues.\n\nRuby versions below 2.5 are soft-deprecated, which means that older versions\nare no longer part of the CI test suite. If any changes have been introduced\nthat break those versions, bug reports and patches will be accepted, but it\nwill be up to the reporter to verify any fixes prior to release. The next\nmajor release will completely break compatibility.".freeze
   s.email = ["halostatue@gmail.com".freeze]
   s.executables = ["htmldiff".freeze, "ldiff".freeze]
   s.extra_rdoc_files = ["Code-of-Conduct.md".freeze, "Contributing.md".freeze, "History.md".freeze, "License.md".freeze, "Manifest.txt".freeze, "README.rdoc".freeze, "docs/COPYING.txt".freeze, "docs/artistic.txt".freeze]

lib/diff/lcs.rb

@@ -49,7 +49,7 @@ module Diff; end unless defined? Diff # rubocop:disable Style/Documentation
 #          a x b y c z p d q
 #    a b c a x b y c z
 module Diff::LCS
-  VERSION = '1.4.3'
+  VERSION = '1.4.4'
 end
 
 require 'diff/lcs/callbacks'
@@ -60,6 +60,13 @@ module Diff::LCS # rubocop:disable Style/Documentation
   # +self+ and +other+. See Diff::LCS#lcs.
   #
   #   lcs = seq1.lcs(seq2)
+  #
+  # A note when using objects: Diff::LCS only works properly when each object
+  # can be used as a key in a Hash, which typically means that the objects must
+  # implement Object#eql? in a way that two identical values compare
+  # identically for key purposes. That is:
+  #
+  #   O.new('a').eql?(O.new('a')) == true
   def lcs(other, &block) #:yields self[i] if there are matched subsequences:
     Diff::LCS.lcs(self, other, &block)
   end

lib/diff/lcs/block.rb

@@ -19,7 +19,7 @@ def initialize(chunk)
   end
 
   def diff_size
-    (@insert.size - @remove.size).abs
+    @insert.size - @remove.size
   end
 
   def op