Change HashDiff Constant to Hashdiff

Why This Change Is Necessary
========================================================================

The name of this gem is `hashdiff`. There is another gem named
`hash_diff`. When they are both required via dependencies, errors are
thrown. Additionally since the behavior is different, gems that are
relying on `hashdiff`'s behavior, may get `hash_diff`'s behavior and
vice versa.

The reason for the conflict is because, based on ruby conventions, _'s
are the separators for camel case.

So:

```ruby
'hashdiff'.camelize # => "Hashdiff"

'hash_diff'.camelize # => "HashDiff"
```

Unfortunately instead of making the base module of this gem `Hashdiff`,
it's called `HashDiff` and it conflicts.

How These Changes Address the Issue
========================================================================

We change all of the constants to the new constant, including in
documentation and tests.

Then we add a shim to allow the old constant to be used and therefore
maintain backward compatibility.

Finally we add a warning message for users of the gem that the old
constant will be removed in the next major version bump.

Side Effects Caused By This Change
========================================================================

A new warning is added when loading the gem.

README.md

@@ -1,17 +1,17 @@
-# HashDiff [![Build Status](https://secure.travis-ci.org/liufengyun/hashdiff.svg)](http://travis-ci.org/liufengyun/hashdiff) [![Gem Version](https://badge.fury.io/rb/hashdiff.svg)](http://badge.fury.io/rb/hashdiff)
+# Hashdiff [![Build Status](https://secure.travis-ci.org/liufengyun/hashdiff.svg)](http://travis-ci.org/liufengyun/hashdiff) [![Gem Version](https://badge.fury.io/rb/hashdiff.svg)](http://badge.fury.io/rb/hashdiff)
 
-HashDiff is a ruby library to compute the smallest difference between two hashes.
+Hashdiff is a ruby library to compute the smallest difference between two hashes.
 
 It also supports comparing two arrays.
 
-HashDiff does not monkey-patch any existing class. All features are contained inside the `HashDiff` module.
+Hashdiff does not monkey-patch any existing class. All features are contained inside the `Hashdiff` module.
 
 **Docs**: [Documentation](http://rubydoc.info/gems/hashdiff)
 
 
 __WARNING__: Don't use the library for comparing large arrays, say ~10K (see #49).
 
-## Why HashDiff?
+## Why Hashdiff?
 
 Given two Hashes A and B, sometimes you face the question: what's the smallest modification that can be made to change A into B?
 
@@ -21,7 +21,7 @@ An algorithm that responds to this question has to do following:
 * Compute recursively -- Arrays and Hashes may be nested arbitrarily in A or B.
 * Compute the smallest change -- it should recognize similar child Hashes or child Arrays between A and B.
 
-HashDiff answers the question above using an opinionated approach:
+Hashdiff answers the question above using an opinionated approach:
 
 * Hash can be represented as a list of (dot-syntax-path, value) pairs. For example, `{a:[{c:2}]}` can be represented as `["a[0].c", 2]`.
 * The change set can be represented using the dot-syntax representation. For example, `[['-', 'b.x', 3], ['~', 'b.z', 45, 30], ['+', 'b.y', 3]]`.
@@ -46,7 +46,7 @@ Two simple hashes:
 a = {a:3, b:2}
 b = {}
 
-diff = HashDiff.diff(a, b)
+diff = Hashdiff.diff(a, b)
 diff.should == [['-', 'a', 3], ['-', 'b', 2]]
 ```
 
@@ -56,7 +56,7 @@ More complex hashes:
 a = {a:{x:2, y:3, z:4}, b:{x:3, z:45}}
 b = {a:{y:3}, b:{y:3, z:30}}
 
-diff = HashDiff.diff(a, b)
+diff = Hashdiff.diff(a, b)
 diff.should == [['-', 'a.x', 2], ['-', 'a.z', 4], ['-', 'b.x', 3], ['~', 'b.z', 45, 30], ['+', 'b.y', 3]]
 ```
 
@@ -66,7 +66,7 @@ Arrays in hashes:
 a = {a:[{x:2, y:3, z:4}, {x:11, y:22, z:33}], b:{x:3, z:45}}
 b = {a:[{y:3}, {x:11, z:33}], b:{y:22}}
 
-diff = HashDiff.best_diff(a, b)
+diff = Hashdiff.best_diff(a, b)
 diff.should == [['-', 'a[0].x', 2], ['-', 'a[0].z', 4], ['-', 'a[1].y', 22], ['-', 'b.x', 3], ['-', 'b.z', 45], ['+', 'b.y', 22]]
 ```
 
@@ -78,8 +78,8 @@ patch example:
 a = {'a' => 3}
 b = {'a' => {'a1' => 1, 'a2' => 2}}
 
-diff = HashDiff.diff(a, b)
-HashDiff.patch!(a, diff).should == b
+diff = Hashdiff.diff(a, b)
+Hashdiff.patch!(a, diff).should == b
 ```
 
 unpatch example:
@@ -88,8 +88,8 @@ unpatch example:
 a = [{'a' => 1, 'b' => 2, 'c' => 3, 'd' => 4, 'e' => 5}, {'x' => 5, 'y' => 6, 'z' => 3}, 1]
 b = [1, {'a' => 1, 'b' => 2, 'c' => 3, 'e' => 5}]
 
-diff = HashDiff.diff(a, b) # diff two array is OK
-HashDiff.unpatch!(b, diff).should == a
+diff = Hashdiff.diff(a, b) # diff two array is OK
+Hashdiff.unpatch!(b, diff).should == a
 ```
 
 ### Options
@@ -106,7 +106,7 @@ You can specify `:delimiter` to be something other than the default dot. For exa
 a = {a:{x:2, y:3, z:4}, b:{x:3, z:45}}
 b = {a:{y:3}, b:{y:3, z:30}}
 
-diff = HashDiff.diff(a, b, :delimiter => '\t')
+diff = Hashdiff.diff(a, b, :delimiter => '\t')
 diff.should == [['-', 'a\tx', 2], ['-', 'a\tz', 4], ['-', 'b\tx', 3], ['~', 'b\tz', 45, 30], ['+', 'b\ty', 3]]
 ```
 
@@ -126,7 +126,7 @@ The :numeric_tolerance option allows for a small numeric tolerance.
 a = {x:5, y:3.75, z:7}
 b = {x:6, y:3.76, z:7}
 
-diff = HashDiff.diff(a, b, :numeric_tolerance => 0.1)
+diff = Hashdiff.diff(a, b, :numeric_tolerance => 0.1)
 diff.should == [["~", "x", 5, 6]]
 ```
 
@@ -138,7 +138,7 @@ The :strip option strips all strings before comparing.
 a = {x:5, s:'foo '}
 b = {x:6, s:'foo'}
 
-diff = HashDiff.diff(a, b, :comparison => { :numeric_tolerance => 0.1, :strip => true })
+diff = Hashdiff.diff(a, b, :comparison => { :numeric_tolerance => 0.1, :strip => true })
 diff.should == [["~", "x", 5, 6]]
 ```
 
@@ -150,7 +150,7 @@ The :case_insensitive option makes string comparisons ignore case.
 a = {x:5, s:'FooBar'}
 b = {x:6, s:'foobar'}
 
-diff = HashDiff.diff(a, b, :comparison => { :numeric_tolerance => 0.1, :case_insensitive => true })
+diff = Hashdiff.diff(a, b, :comparison => { :numeric_tolerance => 0.1, :case_insensitive => true })
 diff.should == [["~", "x", 5, 6]]
 ```
 
@@ -164,7 +164,7 @@ is useful for `patch!` when used on hashes without string keys.
 a = {x:5}
 b = {'x'=>6}
 
-diff = HashDiff.diff(a, b, :array_path => true)
+diff = Hashdiff.diff(a, b, :array_path => true)
 diff.should == [['-', [:x], 5], ['+', ['x'], 6]]
 ```
 
@@ -173,7 +173,7 @@ For cases where there are arrays in paths their index will be added to the path.
 a = {x:[0,1]}
 b = {x:[0,2]}
 
-diff = HashDiff.diff(a, b, :array_path => true)
+diff = Hashdiff.diff(a, b, :array_path => true)
 diff.should == [["-", [:x, 1], 1], ["+", [:x, 1], 2]]
 ```
 
@@ -183,7 +183,7 @@ This shouldn't cause problems if you are comparing an array with a hash:
 a = {x:{0=>1}}
 b = {x:[1]}
 
-diff = HashDiff.diff(a, b, :array_path => true)
+diff = Hashdiff.diff(a, b, :array_path => true)
 diff.should == [["~", [:x], {0=>1}, [1]]]
 ```
 
@@ -205,7 +205,7 @@ Note, currently the :similarity option has no effect when :use_lcs is false.
 a = {x: [0, 1, 2]}
 b = {x: [0, 2, 2, 3]}
 
-diff = HashDiff.diff(a, b, :use_lcs => false)
+diff = Hashdiff.diff(a, b, :use_lcs => false)
 diff.should == [["~", "x[1]", 1, 2], ["+", "x[3]", 3]]
 ```
 
@@ -217,7 +217,7 @@ It's possible to specify how the values of a key should be compared.
 a = {a:'car', b:'boat', c:'plane'}
 b = {a:'bus', b:'truck', c:' plan'}
 
-diff = HashDiff.diff(a, b) do |path, obj1, obj2|
+diff = Hashdiff.diff(a, b) do |path, obj1, obj2|
   case path
   when  /a|b|c/
     obj1.length == obj2.length
@@ -233,7 +233,7 @@ The yielded params of the comparison block is `|path, obj1, obj2|`, in which pat
 a = {a:'car', b:['boat', 'plane'] }
 b = {a:'bus', b:['truck', ' plan'] }
 
-diff = HashDiff.diff(a, b) do |path, obj1, obj2|
+diff = Hashdiff.diff(a, b) do |path, obj1, obj2|
   case path
   when 'b[*]'
     obj1.length == obj2.length
@@ -255,11 +255,11 @@ An order difference alone between two arrays can create too many diffs to be use
 a = {a:'car', b:['boat', 'plane'] }
 b = {a:'car', b:['plane', 'boat'] }
 
-HashDiff.diff(a, b) => [["+", "b[0]", "plane"], ["-", "b[2]", "plane"]]
+Hashdiff.diff(a, b) => [["+", "b[0]", "plane"], ["-", "b[2]", "plane"]]
 
 b[:b].sort!
 
-HashDiff.diff(a, b) => []
+Hashdiff.diff(a, b) => []
 ```
 
 ## Maintainers
@@ -269,4 +269,4 @@ HashDiff.diff(a, b) => []
 
 ## License
 
-HashDiff is distributed under the MIT-LICENSE.
+Hashdiff is distributed under the MIT-LICENSE.

changelog.md

@@ -22,7 +22,7 @@
 
 ## v0.3.4 2017-05-01
 
-* performance improvement of HashDiff#similar? #31
+* performance improvement of `#similar?` #31
 
 ## v0.3.2 2016-12-27
 
@@ -64,7 +64,7 @@
 ## v0.0.5 2012-7-1
 
 * fix a bug in judging whehter two objects are similiar.
-* add more spec test for HashDiff.best_diff
+* add more spec test for `.best_diff`
 
 ## v0.0.4 2012-6-24
 

hashdiff.gemspec

@@ -5,16 +5,17 @@ require 'hashdiff/version'
 
 Gem::Specification.new do |s|
   s.name        = 'hashdiff'
-  s.version     = HashDiff::VERSION
+  s.version     = Hashdiff::VERSION
   s.license     = 'MIT'
-  s.summary     = ' HashDiff is a diff lib to compute the smallest difference between two hashes. '
-  s.description = ' HashDiff is a diff lib to compute the smallest difference between two hashes. '
+  s.summary     = ' Hashdiff is a diff lib to compute the smallest difference between two hashes. '
+  s.description = ' Hashdiff is a diff lib to compute the smallest difference between two hashes. '
 
   s.files         = `git ls-files`.split("\n")
   s.test_files    = `git ls-files -- Appraisals {spec}/*`.split("\n")
 
   s.require_paths = ['lib']
   s.required_ruby_version = Gem::Requirement.new('>= 2.0.0')
+  s.post_install_message = 'The HashDiff constant used by this gem conflicts with another gem of a similar name.  As of version 1.0 the HashDiff constant will be completely removed and replaced by Hashdiff.  For more information see https://github.com/liufengyun/hashdiff/issues/45.'
 
   s.authors = ['Liu Fengyun']
   s.email   = ['[email protected]']

lib/hashdiff.rb

@@ -8,3 +8,7 @@
 require_relative 'hashdiff/diff'
 require_relative 'hashdiff/patch'
 require_relative 'hashdiff/version'
+
+HashDiff = Hashdiff
+
+warn 'The HashDiff constant used by this gem conflicts with another gem of a similar name.  As of version 1.0 the HashDiff constant will be completely removed and replaced by Hashdiff.  For more information see https://github.com/liufengyun/hashdiff/issues/45.'

lib/hashdiff/compare_hashes.rb

@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-module HashDiff
+module Hashdiff
   # @private
   # Used to compare hashes
   class CompareHashes
@@ -19,8 +19,8 @@ def call(obj1, obj2, opts = {})
 
         # add deleted properties
         deleted_keys.each do |k|
-          change_key = HashDiff.prefix_append_key(opts[:prefix], k, opts)
-          custom_result = HashDiff.custom_compare(opts[:comparison], change_key, obj1[k], nil)
+          change_key = Hashdiff.prefix_append_key(opts[:prefix], k, opts)
+          custom_result = Hashdiff.custom_compare(opts[:comparison], change_key, obj1[k], nil)
 
           if custom_result
             result.concat(custom_result)
@@ -31,16 +31,16 @@ def call(obj1, obj2, opts = {})
 
         # recursive comparison for common keys
         common_keys.each do |k|
-          prefix = HashDiff.prefix_append_key(opts[:prefix], k, opts)
+          prefix = Hashdiff.prefix_append_key(opts[:prefix], k, opts)
 
-          result.concat(HashDiff.diff(obj1[k], obj2[k], opts.merge(prefix: prefix)))
+          result.concat(Hashdiff.diff(obj1[k], obj2[k], opts.merge(prefix: prefix)))
         end
 
         # added properties
         added_keys.each do |k|
-          change_key = HashDiff.prefix_append_key(opts[:prefix], k, opts)
+          change_key = Hashdiff.prefix_append_key(opts[:prefix], k, opts)
 
-          custom_result = HashDiff.custom_compare(opts[:comparison], change_key, nil, obj2[k])
+          custom_result = Hashdiff.custom_compare(opts[:comparison], change_key, nil, obj2[k])
 
           if custom_result
             result.concat(custom_result)

lib/hashdiff/diff.rb

@@ -1,9 +1,9 @@
 # frozen_string_literal: true
 
-module HashDiff
+module Hashdiff
   # Best diff two objects, which tries to generate the smallest change set using different similarity values.
   #
-  # HashDiff.best_diff is useful in case of comparing two objects which include similar hashes in arrays.
+  # Hashdiff.best_diff is useful in case of comparing two objects which include similar hashes in arrays.
   #
   # @param [Array, Hash] obj1
   # @param [Array, Hash] obj2
@@ -23,7 +23,7 @@ module HashDiff
   # @example
   #   a = {'x' => [{'a' => 1, 'c' => 3, 'e' => 5}, {'y' => 3}]}
   #   b = {'x' => [{'a' => 1, 'b' => 2, 'e' => 5}] }
-  #   diff = HashDiff.best_diff(a, b)
+  #   diff = Hashdiff.best_diff(a, b)
   #   diff.should == [['-', 'x[0].c', 3], ['+', 'x[0].b', 2], ['-', 'x[1].y', 3], ['-', 'x[1]', {}]]
   #
   # @since 0.0.1
@@ -69,7 +69,7 @@ def self.best_diff(obj1, obj2, options = {}, &block)
   #   a = {"a" => 1, "b" => {"b1" => 1, "b2" =>2}}
   #   b = {"a" => 1, "b" => {}}
   #
-  #   diff = HashDiff.diff(a, b)
+  #   diff = Hashdiff.diff(a, b)
   #   diff.should == [['-', 'b.b1', 1], ['-', 'b.b2', 2]]
   #
   # @since 0.0.1

lib/hashdiff/lcs.rb

@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-module HashDiff
+module Hashdiff
   # @private
   #
   # caculate array difference using LCS algorithm

lib/hashdiff/lcs_compare_arrays.rb

@@ -1,26 +1,26 @@
 # frozen_string_literal: true
 
-module HashDiff
+module Hashdiff
   # @private
   # Used to compare arrays using the lcs algorithm
   class LcsCompareArrays
     class << self
       def call(obj1, obj2, opts = {})
         result = []
 
-        changeset = HashDiff.diff_array_lcs(obj1, obj2, opts) do |lcs|
+        changeset = Hashdiff.diff_array_lcs(obj1, obj2, opts) do |lcs|
           # use a's index for similarity
           lcs.each do |pair|
-            prefix = HashDiff.prefix_append_array_index(opts[:prefix], pair[0], opts)
+            prefix = Hashdiff.prefix_append_array_index(opts[:prefix], pair[0], opts)
 
-            result.concat(HashDiff.diff(obj1[pair[0]], obj2[pair[1]], opts.merge(prefix: prefix)))
+            result.concat(Hashdiff.diff(obj1[pair[0]], obj2[pair[1]], opts.merge(prefix: prefix)))
           end
         end
 
         changeset.each do |change|
           next if change[0] != '-' && change[0] != '+'
 
-          change_key = HashDiff.prefix_append_array_index(opts[:prefix], change[1], opts)
+          change_key = Hashdiff.prefix_append_array_index(opts[:prefix], change[1], opts)
 
           result << [change[0], change_key, change[2]]
         end

lib/hashdiff/linear_compare_array.rb

@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-module HashDiff
+module Hashdiff
   # @private
   #
   # Used to compare arrays in a linear complexity, which produces longer diffs
@@ -80,8 +80,8 @@ def compare_at_index
     end
 
     def item_difference(old_item, new_item, item_index)
-      prefix = HashDiff.prefix_append_array_index(options[:prefix], item_index, options)
-      HashDiff.diff(old_item, new_item, options.merge(prefix: prefix))
+      prefix = Hashdiff.prefix_append_array_index(options[:prefix], item_index, options)
+      Hashdiff.diff(old_item, new_item, options.merge(prefix: prefix))
     end
 
     # look ahead in the new array to see if the current item appears later
@@ -137,12 +137,12 @@ def append_deletions_before_match(match_index)
     end
 
     def append_addition(item, index)
-      key = HashDiff.prefix_append_array_index(options[:prefix], index, options)
+      key = Hashdiff.prefix_append_array_index(options[:prefix], index, options)
       additions << ['+', key, item]
     end
 
     def append_deletion(item, index)
-      key = HashDiff.prefix_append_array_index(options[:prefix], index, options)
+      key = Hashdiff.prefix_append_array_index(options[:prefix], index, options)
       deletions << ['-', key, item]
     end
 

lib/hashdiff/patch.rb

@@ -3,7 +3,7 @@
 #
 # This module provides methods to diff two hash, patch and unpatch hash
 #
-module HashDiff
+module Hashdiff
   # Apply patch to object
   #
   # @param [Hash, Array] obj the object to be patched, can be an Array or a Hash

lib/hashdiff/util.rb

@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-module HashDiff
+module Hashdiff
   # @private
   #
   # judge whether two objects are similar