Check whether special is active by tag name or by id

[jostephd]

Currently, checking whether a weapon special is active is done by looking for a weapon special whose tag name or id match the specified value:

wesnoth/src/units/abilities.cpp

Lines 607 to 614 in 80b00fc

	/**
	* Returns whether or not @a *this has a special with a tag or id equal to
	* @a special. If @a simple_check is set to true, then the check is merely
	* for being present. Otherwise (the default), the check is for a special
	* active in the current context (see set_specials_context), including
	* specials obtained from the opponent's attack.
	*/
	bool attack_type::get_special_bool(const std::string& special, bool simple_check) const

For example, the initiative special in HttT would be matched by either special_active=initiative or special_active=firststrike:

wesnoth/data/campaigns/Heir_To_The_Throne/utils/abilities.cfg

Lines 4 to 14 in 80b00fc

	[firststrike]
	id=initiative
	name= _ "initiative"
	description= _ "All adjacent friendly units will strike first in melee combat, even when defending."
	affect_self=no
	[filter_second_weapon]
	range=melee
	[/filter_second_weapon]
	[affect_adjacent]
	[/affect_adjacent]
	[/firststrike]

Which can be confusing, because some tag names are also used as ids:

wesnoth/data/core/macros/abilities.cfg

Lines 402 to 406 in 80b00fc

	[firststrike]
	id=firststrike
	name= _ "first strike"
	description= _ "This unit always strikes first with this attack, even if they are defending."
	[/firststrike]

It would be good to separate "search by tag name" and "search by id" and expose that in StandardWeaponFilter, as @gfgtdf said in #3800 (comment).

Labeling "Good first issue" since this isn't a difficult change, but it will require some work on the C++ side.

[newfrenchy83]

resolve in #3920

[newfrenchy83]

@jostephd, please lookk also #4424, what this issue was reolved(or ot) BEFORE beta version

[jostephd]

Thanks for the reminder. Milestoned as requested.

[jostephd]

Reopening until documentation is updated, see #4424 (review)