From 8674417358b56d382f5615b9a4a464e9c862969c Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Wojciech=20Wn=C4=99trzak?= <w.wnetrzak@gmail.com>
Date: Wed, 7 Aug 2019 18:31:33 +0200
Subject: [PATCH] Support multiple arguments in `HashWithIndifferentAccess` for
 `merge` and `update` methods

It follows Ruby 2.6 addition https://github.com/ruby/ruby/pull/1951
---
 activesupport/CHANGELOG.md                    |  5 +++
 .../hash_with_indifferent_access.rb           | 39 ++++++++++++-------
 .../test/hash_with_indifferent_access_test.rb | 16 ++++++++
 3 files changed, 47 insertions(+), 13 deletions(-)

diff --git a/activesupport/CHANGELOG.md b/activesupport/CHANGELOG.md
index dad7005eb1..ce5a22bea6 100644
--- a/activesupport/CHANGELOG.md
+++ b/activesupport/CHANGELOG.md
@@ -1,3 +1,8 @@
+*   Support multiple arguments in `HashWithIndifferentAccess` for `merge` and `update` methods, to
+    follow Ruby 2.6 addition.
+
+    *Wojciech Wnętrzak*
+
 *   Allow initializing `thread_mattr_*` attributes via `:default` option
 
         class Scraper
diff --git a/activesupport/lib/active_support/hash_with_indifferent_access.rb b/activesupport/lib/active_support/hash_with_indifferent_access.rb
index 6acf64cb39..9f4d3e6ef3 100644
--- a/activesupport/lib/active_support/hash_with_indifferent_access.rb
+++ b/activesupport/lib/active_support/hash_with_indifferent_access.rb
@@ -96,7 +96,7 @@ module ActiveSupport
 
     alias_method :store, :[]=
 
-    # Updates the receiver in-place, merging in the hash passed as argument:
+    # Updates the receiver in-place, merging in the hashes passed as argument:
     #
     #   hash_1 = ActiveSupport::HashWithIndifferentAccess.new
     #   hash_1[:key] = 'value'
@@ -106,7 +106,10 @@ module ActiveSupport
     #
     #   hash_1.update(hash_2) # => {"key"=>"New Value!"}
     #
-    # The argument can be either an
+    #   hash = ActiveSupport::HashWithIndifferentAccess.new
+    #   hash.update({ "a" => 1 }, { "b" => 2 }) # => { "a" => 1, "b" => 2 }
+    #
+    # The arguments can be either an
     # <tt>ActiveSupport::HashWithIndifferentAccess</tt> or a regular +Hash+.
     # In either case the merge respects the semantics of indifferent access.
     #
@@ -121,18 +124,15 @@ module ActiveSupport
     #   hash_1[:key] = 10
     #   hash_2['key'] = 12
     #   hash_1.update(hash_2) { |key, old, new| old + new } # => {"key"=>22}
-    def update(other_hash)
-      if other_hash.is_a? HashWithIndifferentAccess
-        super(other_hash)
+    def update(*other_hashes, &block)
+      if other_hashes.one?
+        update_with_single_argument(other_hashes.first, block)
       else
-        other_hash.to_hash.each_pair do |key, value|
-          if block_given? && key?(key)
-            value = yield(convert_key(key), self[key], value)
-          end
-          regular_writer(convert_key(key), convert_value(value))
+        other_hashes.each do |other_hash|
+          update_with_single_argument(other_hash, block)
         end
-        self
       end
+      self
     end
 
     alias_method :merge!, :update
@@ -259,8 +259,8 @@ module ActiveSupport
     # This method has the same semantics of +update+, except it does not
     # modify the receiver but rather returns a new hash with indifferent
     # access with the result of the merge.
-    def merge(hash, &block)
-      dup.update(hash, &block)
+    def merge(*hashes, &block)
+      dup.update(*hashes, &block)
     end
 
     # Like +merge+ but the other way around: Merges the receiver into the
@@ -393,6 +393,19 @@ module ActiveSupport
           target.default = default
         end
       end
+
+      def update_with_single_argument(other_hash, block)
+        if other_hash.is_a? HashWithIndifferentAccess
+          regular_update(other_hash, &block)
+        else
+          other_hash.to_hash.each_pair do |key, value|
+            if block && key?(key)
+              value = block.call(convert_key(key), self[key], value)
+            end
+            regular_writer(convert_key(key), convert_value(value))
+          end
+        end
+      end
   end
 end
 
diff --git a/activesupport/test/hash_with_indifferent_access_test.rb b/activesupport/test/hash_with_indifferent_access_test.rb
index af96231801..921a5c115d 100644
--- a/activesupport/test/hash_with_indifferent_access_test.rb
+++ b/activesupport/test/hash_with_indifferent_access_test.rb
@@ -249,6 +249,14 @@ class HashWithIndifferentAccessTest < ActiveSupport::TestCase
     assert [updated_with_strings, updated_with_symbols, updated_with_mixed].all? { |h| h.keys.size == 2 }
   end
 
+  def test_update_with_multiple_arguments
+    hash = HashWithIndifferentAccess.new
+    hash.update({ "a" => 1 }, { "b" => 2 })
+
+    assert_equal 1, hash["a"]
+    assert_equal 2, hash["b"]
+  end
+
   def test_update_with_to_hash_conversion
     hash = HashWithIndifferentAccess.new
     hash.update HashByConversion.new(a: 1)
@@ -274,6 +282,14 @@ class HashWithIndifferentAccessTest < ActiveSupport::TestCase
     assert_equal 2, hash["b"]
   end
 
+  def test_merging_with_multiple_arguments
+    hash = HashWithIndifferentAccess.new
+    merged = hash.merge({ "a" => 1 }, { "b" => 2 })
+
+    assert_equal 1, merged["a"]
+    assert_equal 2, merged["b"]
+  end
+
   def test_merge_with_to_hash_conversion
     hash = HashWithIndifferentAccess.new
     merged = hash.merge HashByConversion.new(a: 1)