Better support for overriding options programmatically

[ameir]

Hello,

I am currently setting options from a file, similar to what is described in #413.

An issue I am having is that the options loaded in this way bypass validation, so bogus parameters can be inserted, and (more importantly for my case), type validation is not attempted. For example, if a Thor option is changed from a string to an array, if the config file sets that option as a string, it will remain as a string in the options hash. If code is dependent on this option being an array, things begin to fall apart.

If there's a way to instead merge a hash with the hash from

thor/lib/thor/parser/options.rb

Lines 88 to 139 in e4907fd

	def parse(args) # rubocop:disable Metrics/MethodLength
	@pile = args.dup
	@is_treated_as_value = false
	@parsing_options = true
	while peek
	if parsing_options?
	match, is_switch = current_is_switch?
	shifted = shift
	if is_switch
	case shifted
	when SHORT_SQ_RE
	unshift($1.split("").map { |f| "-#{f}" })
	next
	when EQ_RE
	unshift($2, :is_value => true)
	switch = $1
	when SHORT_NUM
	unshift($2)
	switch = $1
	when LONG_RE, SHORT_RE
	switch = $1
	end
	switch = normalize_switch(switch)
	option = switch_option(switch)
	result = parse_peek(switch, option)
	assign_result!(option, result)
	elsif @stop_on_unknown
	@parsing_options = false
	@extra << shifted
	@stopped_parsing_after_extra_index ||= @extra.size
	@extra << shift while peek
	break
	elsif match
	@extra << shifted
	@extra << shift while peek && peek !~ /^-/
	else
	@extra << shifted
	end
	else
	@extra << shift
	end
	end
	check_requirement! unless @disable_required_check
	assigns = Thor::CoreExt::HashWithIndifferentAccess.new(@assigns)
	assigns.freeze
	assigns
	end

, that would probably work (i.e. override that method and merge one hash over the other). One issue with this (and the original method) is that defaults are resolved without us knowing if option values are default or user-provided. If there's a way to provide the initial hash before defaults are resolved, that would be ideal.

Thank you!