Building new records with enum scopes now works as expected

Previously, this would give an `ArgumentError`:

   class Issue < ActiveRecord::Base
     enum :status, [:open, :finished]
   end

   Issue.open.build # => ArgumentError: '0' is not a valid status
   Issue.open.create # => ArgumentError: '0' is not a valid status

PR #13542 muted the error, but the issue remains. This commit fixes
the issue by allowing the enum value to be written directly via the
setter:

   Issue.new.status = 0 # This now sets status to :open

Assigning a value directly via the setter like this is not part of the
documented public API, so users should not rely on this behavior.

Closes #13530.

1 files changed, 7 insertions, 6 deletions

diff --git a/activerecord/test/cases/enum_test.rb b/activerecord/test/cases/enum_test.rb
index 47e3dfc3ad..c09e58fbf1 100644
--- a/activerecord/test/cases/enum_test.rb
+++ b/activerecord/test/cases/enum_test.rb
@@ -79,12 +79,13 @@ class EnumTest < ActiveRecord::TestCase
     assert_equal 2, Book::STATUS[:published]
   end
 
-  test "first_or_initialize with enums' scopes" do
-    class Issue < ActiveRecord::Base
-      enum status: [:open, :closed]
-    end
+  test "building new objects with enum scopes" do
+    assert Book.written.build.written?
+    assert Book.read.build.read?
+  end
 
-    assert Issue.open.empty?
-    assert Issue.open.first_or_initialize
+  test "creating new objects with enum scopes" do
+    assert Book.written.create.written?
+    assert Book.read.create.read?
   end
 end