Serialize JSON attribute value nil as SQL NULL, not JSON 'null'

Test: JSON attribute value nil can be used in where(attr: nil)

Add changelog entry

2 files changed, 32 insertions, 0 deletions

diff --git a/activerecord/test/cases/adapters/mysql2/json_test.rb b/activerecord/test/cases/adapters/mysql2/json_test.rb
index 6b7d259023..630cdb36a4 100644
--- a/activerecord/test/cases/adapters/mysql2/json_test.rb
+++ b/activerecord/test/cases/adapters/mysql2/json_test.rb
@@ -102,6 +102,22 @@ if ActiveRecord::Base.connection.supports_json?
       assert_equal(["v0", { "k1" => "v1" }], x.payload)
     end
 
+    def test_select_nil_json_after_create
+      json = JsonDataType.create(payload: nil)
+      x = JsonDataType.where(payload:nil).first
+      assert_equal(json, x)
+    end
+
+    def test_select_nil_json_after_update
+      json = JsonDataType.create(payload: "foo")
+      x = JsonDataType.where(payload:nil).first
+      assert_equal(nil, x)
+
+      json.update_attributes payload: nil
+      x = JsonDataType.where(payload:nil).first
+      assert_equal(json.reload, x)
+    end
+
     def test_rewrite_array_json_value
       @connection.execute %q|insert into json_data_type (payload) VALUES ('["v0",{"k1":"v1"}]')|
       x = JsonDataType.first
diff --git a/activerecord/test/cases/adapters/postgresql/json_test.rb b/activerecord/test/cases/adapters/postgresql/json_test.rb
index c74f70f251..273b2c1c7b 100644
--- a/activerecord/test/cases/adapters/postgresql/json_test.rb
+++ b/activerecord/test/cases/adapters/postgresql/json_test.rb
@@ -113,6 +113,22 @@ module PostgresqlJSONSharedTestCases
     assert_equal(nil, x.payload)
   end
 
+  def test_select_nil_json_after_create
+    json = JsonDataType.create(payload: nil)
+    x = JsonDataType.where(payload:nil).first
+    assert_equal(json, x)
+  end
+
+  def test_select_nil_json_after_update
+    json = JsonDataType.create(payload: "foo")
+    x = JsonDataType.where(payload:nil).first
+    assert_equal(nil, x)
+
+    json.update_attributes payload: nil
+    x = JsonDataType.where(payload:nil).first
+    assert_equal(json.reload, x)
+  end
+
   def test_select_array_json_value
     @connection.execute %q|insert into json_data_type (payload) VALUES ('["v0",{"k1":"v1"}]')|
     x = JsonDataType.first