Fix the enums writer methods

Previously, the writer methods would simply check whether the passed
argument was the symbol representing the integer value of an enum field.
Therefore, it was not possible to specify the numeric value itself but
the dynamically defined scopes generate where clauses relying on this
kind of values so a chained call to a method like `find_or_initialize_by`
would trigger an `ArgumentError`.

Reference #13530

3 files changed, 15 insertions, 2 deletions

diff --git a/activerecord/lib/active_record/enum.rb b/activerecord/lib/active_record/enum.rb
index 1d484f7c15..aebb061717 100644
--- a/activerecord/lib/active_record/enum.rb
+++ b/activerecord/lib/active_record/enum.rb
@@ -67,7 +67,7 @@ module ActiveRecord
         _enum_methods_module.module_eval do
           # def status=(value) self[:status] = STATUS[value] end
           define_method("#{name}=") { |value|
-            unless enum_values.has_key?(value) || value.blank?
+            unless enum_values.has_key?(value) || enum_values.has_value?(value) || value.blank?
               raise ArgumentError, "'#{value}' is not a valid #{name}"
             end
             self[name] = enum_values[value]
diff --git a/activerecord/test/cases/enum_test.rb b/activerecord/test/cases/enum_test.rb
index 017edcb194..47e3dfc3ad 100644
--- a/activerecord/test/cases/enum_test.rb
+++ b/activerecord/test/cases/enum_test.rb
@@ -16,7 +16,7 @@ class EnumTest < ActiveRecord::TestCase
     assert @book.unread?
   end
 
-  test "query state with symbol" do
+  test "query state with strings" do
     assert_equal "proposed", @book.status
     assert_equal "unread", @book.read_status
   end
@@ -78,4 +78,13 @@ class EnumTest < ActiveRecord::TestCase
     assert_equal 1, Book::STATUS["written"]
     assert_equal 2, Book::STATUS[:published]
   end
+
+  test "first_or_initialize with enums' scopes" do
+    class Issue < ActiveRecord::Base
+      enum status: [:open, :closed]
+    end
+
+    assert Issue.open.empty?
+    assert Issue.open.first_or_initialize
+  end
 end
diff --git a/activerecord/test/schema/schema.rb b/activerecord/test/schema/schema.rb
index ac546fc296..9f504801af 100644
--- a/activerecord/test/schema/schema.rb
+++ b/activerecord/test/schema/schema.rb
@@ -327,6 +327,10 @@ ActiveRecord::Schema.define do
     t.string     :color
   end
 
+  create_table :issues, force: true do |t|
+    t.integer :status
+  end
+
   create_table :items, force: true do |t|
     t.column :name, :string
   end