New rules for "blood moon" cards

[JayDi85]

Issue from reddit.

Is xMage work correct with new rule changes for "blood moon" cards? You can read about changes on that page (search by "614.12, 614.16d").

So this rule's changing. Now, to determine what replacement effects will apply to a permanent entering the battlefield, you look at continuous effects that modify that permanent's characteristics coming from the permanent itself along with those that already exist and will affect that permanent. Dimir Aqueduct enters the battlefield untapped under Blood Moon. Humility causes creatures with modular to enter without their +1/+1 counters. Metallic Mimic can distribute +1/+1 counters happily to your army of Ferrets under Arcane Adaptation.

[theelk801]

Yeah, we know about these but they're hard to implement given that they need to look forward in time in order to apply. I'll try to figure something out.

[JayDi85]

Card review with many possible rules and situations from mtg judges:
http://cantrip.ru/en/mtg-cards/Blood-Moon.shtml

[LevelX2]

from jeffwadsworth:
https://magic.wizards.com/en/articles/archive/news/ixalan-comprehensive-rules-changes-2017-09-28

Essentially, any effect that would affect the card coming into the battlefield gets applied before it actually enters the battlefield. So a 1/1 white creature would be a 2/2 when it enters the battlefield with a Crusade in play, not a 1/1 that gets boosted to 2/2. It is a very fundamental change.

[LevelX2]

The core of the new behaviour 614.12

Now, to determine what replacement effects will apply to a permanent entering the battlefield, you look at continuous effects that modify that permanent's characteristics coming from the permanent itself along with those that already exist and will affect that permanent.

Rules

Characteristic-defining ability

• 604.3. Some static abilities are characteristic-defining abilities. A characteristic-defining ability conveys information about an object’s characteristics that would normally be found elsewhere on that object (such as in its mana cost, type line, or power/toughness box) or overrides information found elsewhere on that object. Characteristic-defining abilities function in all zones. They also function outside the game.
• 604.3a A static ability is a characteristic-defining ability if it meets the following criteria: (1) It defines an object’s colors, subtypes, power, or toughness; (2) it is printed on the card it affects, it was granted to the token it affects by the effect that created the token, or it was acquired by the object it affects as the result of a copy effect or text-changing effect; (3) it does not directly affect the characteristics of any other objects; (4) it is not an ability that an object grants to itself; and (5) it does not set the values of such characteristics only if certain conditions are met.

614. Replacement Effects

• 614.12. Some replacement effects modify how a permanent enters the battlefield. (See rules 614.1c–d.) Such effects may come from the permanent itself if they affect only that permanent (as opposed to a general subset of permanents that includes it). They may also come from other sources. To determine which replacement effects apply and how they apply, check the characteristics of the permanent as it would exist on the battlefield, taking into account replacement effects that have already modified how it enters the battlefield (see rule 616.1), continuous effects from the permanent’s own static abilities that would apply to it once it’s on the battlefield, and continuous effects that already exist and would apply to the permanent.

Example: Voice of All says “As Voice of All enters the battlefield, choose a color” and “Voice of All has protection from the chosen color.” An effect creates a token that’s a copy of Voice of All. As that token is created, the token’s controller chooses a color for it.

Example: Yixlid Jailer says “Cards in graveyards lose all abilities.” Scarwood Treefolk says “Scarwood Treefolk enters the battlefield tapped.” A Scarwood Treefolk that’s put onto the battlefield from a graveyard enters the battlefield tapped.

Example: Orb of Dreams is an artifact that says “Permanents enter the battlefield tapped.” It won’t affect itself, so Orb of Dreams enters the battlefield untapped.

• 614.12a If a replacement effect that modifies how a permanent enters the battlefield requires a choice, that choice is made before the permanent enters the battlefield.
• 614.12b Some replacement effects cause a permanent to enter the battlefield with its controller’s choice of one of two abilities, each marked with an anchor word and preceded by a bullet point. “[Anchor word] — [ability]” means “As long as [anchor word] was chosen as this permanent entered the battlefield, this permanent has [ability].” The abilities preceded by anchor words are each linked to the ability that causes a player to choose between them. See rule 607, “Linked Abilities.”

What has to happen in xmage if a permanent enters the battlefield?

1. Determine which continuous effects from the permanent itself modify that permanent's characteristics.
2. Determine which already existing continuous effects modify that permanent's characteristics.
3. Apply that continuous effects to the permanent before entering.
4. Let the permanent enter the battlefield. So "enters the battlefield" replacement effects act on base of the already modified characteristics of the entering permanent.

Beside the yet not clear way how to do that, is that list and the order of the list correct?
Does this list miss something that has to be taken into account also?

Any suggestions/additions welcome!