Fix `deserialize` with JSON array

Fixes #28285.

3 files changed, 17 insertions, 1 deletions

diff --git a/activerecord/CHANGELOG.md b/activerecord/CHANGELOG.md
index abc415ea14..b2c57e792f 100644
--- a/activerecord/CHANGELOG.md
+++ b/activerecord/CHANGELOG.md
@@ -1,3 +1,9 @@
+*   Fix `deserialize` with JSON array.
+
+    Fixes #28285.
+
+    *Ryuta Kamizono*
+
 *   Fix `rake db:schema:load` with subdirectories.
 
     *Ryuta Kamizono*
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql/oid/array.rb b/activerecord/lib/active_record/connection_adapters/postgresql/oid/array.rb
index e1a75f8e5e..a73a8c1726 100644
--- a/activerecord/lib/active_record/connection_adapters/postgresql/oid/array.rb
+++ b/activerecord/lib/active_record/connection_adapters/postgresql/oid/array.rb
@@ -23,7 +23,7 @@ module ActiveRecord
             when ::String
               type_cast_array(@pg_decoder.decode(value), :deserialize)
             when Data
-              deserialize(value.values)
+              type_cast_array(value.values, :deserialize)
             else
               super
             end
diff --git a/activerecord/test/cases/adapters/postgresql/json_test.rb b/activerecord/test/cases/adapters/postgresql/json_test.rb
index 93558ac4d2..d4e627001c 100644
--- a/activerecord/test/cases/adapters/postgresql/json_test.rb
+++ b/activerecord/test/cases/adapters/postgresql/json_test.rb
@@ -16,6 +16,7 @@ module PostgresqlJSONSharedTestCases
       @connection.create_table("json_data_type") do |t|
         t.public_send column_type, "payload", default: {} # t.json 'payload', default: {}
         t.public_send column_type, "settings"             # t.json 'settings'
+        t.public_send column_type, "objects", array: true # t.json 'objects', array: true
       end
     rescue ActiveRecord::StatementInvalid
       skip "do not test on PostgreSQL without #{column_type} type."
@@ -75,6 +76,15 @@ module PostgresqlJSONSharedTestCases
     assert_equal({ "string" => "foo", "symbol" => "bar" }, x.reload.payload)
   end
 
+  def test_deserialize_with_array
+    x = JsonDataType.new(objects: ["foo" => "bar"])
+    assert_equal ["foo" => "bar"], x.objects
+    x.save!
+    assert_equal ["foo" => "bar"], x.objects
+    x.reload
+    assert_equal ["foo" => "bar"], x.objects
+  end
+
   def test_type_cast_json
     type = JsonDataType.type_for_attribute("payload")