Merge pull request rails#53937 from fatkodima/mysql-fix-remove-foreign-key-restrict

Fix removing foreign keys with `:restrict` action for MySQL

Author: byroot

activerecord/lib/active_record/connection_adapters/mysql/schema_statements.rb

@@ -85,6 +85,13 @@ def create_table(table_name, options: default_row_format, **)
           super
         end
 
+        def remove_foreign_key(from_table, to_table = nil, **options)
+          # RESTRICT is by default in MySQL.
+          options.delete(:on_update) if options[:on_update] == :restrict
+          options.delete(:on_delete) if options[:on_delete] == :restrict
+          super
+        end
+
         def internal_string_options_for_primary_key
           super.tap do |options|
             if !row_format_dynamic_by_default? && CHARSETS_OF_4BYTES_MAXLEN.include?(charset)

activerecord/test/cases/migration/foreign_key_test.rb

@@ -468,6 +468,13 @@ def test_remove_foreign_key_by_the_select_one_on_the_same_table
             @connection.foreign_keys("astronauts").map { |fk| [fk.from_table, fk.to_table, fk.column] }
         end
 
+        def test_remove_foreign_key_with_restrict_action
+          @connection.add_foreign_key :astronauts, :rockets, on_delete: :restrict
+          assert_equal 1, @connection.foreign_keys("astronauts").size
+          @connection.remove_foreign_key :astronauts, :rockets, on_delete: :restrict
+          assert_empty @connection.foreign_keys("astronauts")
+        end
+
         if ActiveRecord::Base.lease_connection.supports_validate_constraints?
           def test_add_invalid_foreign_key
             @connection.add_foreign_key :astronauts, :rockets, column: "rocket_id", validate: false