Unknown key: :on. Valid keys are: :if, :unless, :prepend (ArgumentError)

[deepakmahakale]

Getting the following error while upgrading the application from rails 5.2 to 6.0

Unknown key: :on. Valid keys are: :if, :unless, :prepend (ArgumentError)

Ruby: 2.5.1
Rails: 6.0.3.3

Solution:
Fix here -

activerecord-userstamp/lib/active_record/userstamp/stampable.rb

Lines 15 to 17 in 752f1e3

	before_validation :set_creator_attribute, on: :create, if: :record_userstamp
	before_save :set_updater_attribute, if: :record_userstamp
	before_save :set_creator_attribute, on: :create, if: :record_userstamp

	28: from /home/deepak/.rvm/gems/ruby-2.5.1@my_project/bundler/gems/activerecord-userstamp-8b0a51a84b86/lib/activerecord/userstamp.rb:1:in `<top (required)>'
	27: from /home/deepak/.rvm/gems/ruby-2.5.1@my_project/gems/activesupport-6.0.3.3/lib/active_support/dependencies.rb:324:in `require'
	26: from /home/deepak/.rvm/gems/ruby-2.5.1@my_project/gems/activesupport-6.0.3.3/lib/active_support/dependencies.rb:291:in `load_dependency'
	25: from /home/deepak/.rvm/gems/ruby-2.5.1@my_project/gems/activesupport-6.0.3.3/lib/active_support/dependencies.rb:324:in `block in require'
	24: from /home/deepak/.rvm/gems/ruby-2.5.1@my_project/gems/activesupport-6.0.3.3/lib/active_support/dependencies.rb:324:in `require'
	23: from /home/deepak/.rvm/gems/ruby-2.5.1@my_project/bundler/gems/activerecord-userstamp-8b0a51a84b86/lib/active_record/userstamp.rb:1:in `<top (required)>'
	22: from /home/deepak/.rvm/gems/ruby-2.5.1@my_project/bundler/gems/activerecord-userstamp-8b0a51a84b86/lib/active_record/userstamp.rb:29:in `<module:Userstamp>'
	21: from /home/deepak/.rvm/gems/ruby-2.5.1@my_project/gems/activesupport-6.0.3.3/lib/active_support/dependencies/autoload.rb:72:in `eager_load!'
	20: from /home/deepak/.rvm/gems/ruby-2.5.1@my_project/gems/activesupport-6.0.3.3/lib/active_support/dependencies/autoload.rb:72:in `each_value'
	19: from /home/deepak/.rvm/gems/ruby-2.5.1@my_project/gems/activesupport-6.0.3.3/lib/active_support/dependencies/autoload.rb:72:in `block in eager_load!'
	18: from /home/deepak/.rvm/gems/ruby-2.5.1@my_project/gems/activesupport-6.0.3.3/lib/active_support/dependencies.rb:324:in `require'
	17: from /home/deepak/.rvm/gems/ruby-2.5.1@my_project/gems/activesupport-6.0.3.3/lib/active_support/dependencies.rb:291:in `load_dependency'
	16: from /home/deepak/.rvm/gems/ruby-2.5.1@my_project/gems/activesupport-6.0.3.3/lib/active_support/dependencies.rb:324:in `block in require'
	15: from /home/deepak/.rvm/gems/ruby-2.5.1@my_project/gems/activesupport-6.0.3.3/lib/active_support/dependencies.rb:324:in `require'
	14: from /home/deepak/.rvm/gems/ruby-2.5.1@my_project/bundler/gems/activerecord-userstamp-8b0a51a84b86/lib/active_record/userstamp/model_additions.rb:8:in `<top (required)>'
	13: from /home/deepak/.rvm/gems/ruby-2.5.1@my_project/bundler/gems/activerecord-userstamp-8b0a51a84b86/lib/active_record/userstamp/model_additions.rb:8:in `class_eval'
	12: from /home/deepak/.rvm/gems/ruby-2.5.1@my_project/bundler/gems/activerecord-userstamp-8b0a51a84b86/lib/active_record/userstamp/model_additions.rb:9:in `block in <top (required)>'
	11: from /home/deepak/.rvm/gems/ruby-2.5.1@my_project/bundler/gems/activerecord-userstamp-8b0a51a84b86/lib/active_record/userstamp/model_additions.rb:9:in `include'
	10: from /home/deepak/.rvm/gems/ruby-2.5.1@my_project/gems/activesupport-6.0.3.3/lib/active_support/concern.rb:119:in `append_features'
	 9: from /home/deepak/.rvm/gems/ruby-2.5.1@my_project/gems/activesupport-6.0.3.3/lib/active_support/concern.rb:119:in `each'
	 8: from /home/deepak/.rvm/gems/ruby-2.5.1@my_project/gems/activesupport-6.0.3.3/lib/active_support/concern.rb:119:in `block in append_features'
	 7: from /home/deepak/.rvm/gems/ruby-2.5.1@my_project/gems/activesupport-6.0.3.3/lib/active_support/concern.rb:119:in `include'
	 6: from /home/deepak/.rvm/gems/ruby-2.5.1@my_project/gems/activesupport-6.0.3.3/lib/active_support/concern.rb:122:in `append_features'
	 5: from /home/deepak/.rvm/gems/ruby-2.5.1@my_project/gems/activesupport-6.0.3.3/lib/active_support/concern.rb:122:in `class_eval'
	 4: from /home/deepak/.rvm/gems/ruby-2.5.1@my_project/bundler/gems/activerecord-userstamp-8b0a51a84b86/lib/active_record/userstamp/stampable.rb:17:in `block in <module:Stampable>'
	 3: from /home/deepak/.rvm/gems/ruby-2.5.1@my_project/gems/activemodel-6.0.3.3/lib/active_model/callbacks.rb:131:in `block in _define_before_model_callback'
	 2: from /home/deepak/.rvm/gems/ruby-2.5.1@my_project/gems/activesupport-6.0.3.3/lib/active_support/core_ext/hash/keys.rb:50:in `assert_valid_keys'
	 1: from /home/deepak/.rvm/gems/ruby-2.5.1@my_project/gems/activesupport-6.0.3.3/lib/active_support/core_ext/hash/keys.rb:50:in `each_key'
/home/deepak/.rvm/gems/ruby-2.5.1@my_project/gems/activesupport-6.0.3.3/lib/active_support/core_ext/hash/keys.rb:52:in `block in assert_valid_keys': Unknown key: :on. Valid keys are: :if, :unless, :prepend (ArgumentError)