Merge pull request #28270 from mmangino/dont_ignore_seralization_options

Don't accidentally lose includes in serialization

3 files changed, 12 insertions, 1 deletions

diff --git a/activemodel/CHANGELOG.md b/activemodel/CHANGELOG.md
index b28c83e4ed..8a3578229a 100644
--- a/activemodel/CHANGELOG.md
+++ b/activemodel/CHANGELOG.md
@@ -1,5 +1,9 @@
 ## Rails 6.0.0.alpha (Unreleased) ##
 
+*   Do not lose all multiple `:includes` with options in serialization.
+
+    *Mike Mangino*
+
 *   Rails 6 requires Ruby 2.4.1 or newer.
 
     *Jeremy Daer*
diff --git a/activemodel/lib/active_model/serialization.rb b/activemodel/lib/active_model/serialization.rb
index 47cb81bee5..c4b7b32291 100644
--- a/activemodel/lib/active_model/serialization.rb
+++ b/activemodel/lib/active_model/serialization.rb
@@ -179,7 +179,7 @@ module ActiveModel
         return unless includes = options[:include]
 
         unless includes.is_a?(Hash)
-          includes = Hash[Array(includes).map { |n| n.is_a?(Hash) ? n.to_a.first : [n, {}] }]
+          includes = Hash[Array(includes).flat_map { |n| n.is_a?(Hash) ? n.to_a : [[n, {}]] }]
         end
 
         includes.each do |association, opts|
diff --git a/activemodel/test/cases/serialization_test.rb b/activemodel/test/cases/serialization_test.rb
index 9002982e7f..6826d2bbd1 100644
--- a/activemodel/test/cases/serialization_test.rb
+++ b/activemodel/test/cases/serialization_test.rb
@@ -174,4 +174,11 @@ class SerializationTest < ActiveModel::TestCase
                            { "name" => "Sue", "email" => "sue@example.com", "gender" => "female" }] }
     assert_equal expected, @user.serializable_hash(include: [{ address: { only: "street" } }, :friends])
   end
+
+  def test_all_includes_with_options
+    expected = { "email" => "david@example.com", "gender" => "male", "name" => "David",
+                "address" => { "street" => "123 Lane" },
+                "friends" => [{ "name" => "Joe" }, { "name" => "Sue" }] }
+    assert_equal expected, @user.serializable_hash(include: [address: { only: "street" }, friends: { only: "name" }])
+  end
 end