Swift End + Bonecrusher Giants with a Clover gives too much damage

[JayDi85]

From reddit:

Just cast Swift End on 2 Bonecrusher Giants with a Clover out. Would expect to take 8 damage for that ((2+2)x2) but as you can see from the screenshot I took 16.

[Paerux]

in case anyone who thought copying spells targeted the original target first and then changed (like me)
here's the official ruling

706.10c Some effects copy a spell or ability and state that its controller may choose new targets for the copy. The player may leave any number of the targets unchanged, even if those targets would be illegal. If the player chooses to change some or all of the targets, the new targets must be legal. Once the player has decided what the copy’s targets will be, the copy is put onto the stack with those targets.

[jeffwadsworth]

This is related to the copied spell retaining the targeted object long enough for the targeted trigger to fire.

[Dilnu]

This is because chooseNewTarget fires off many more events than are required. You can actually trigger arbitrarily many targeted events if you play in certain ways.

I spent a few hours trying to find a solution but I had no luck.

The main problem is that we don't have a way of imposing additional requirements when retargeting a spell as a result the implementation of chooseNewTarget in StackObjectImpl has loops and those loops allow for the arbitrary number of events I mentioned.

The other work around would be to add a skip event parameter chooseTargets method in every Target and player subclass but that's also really painful.

The final possibility which occurs to me is to somehow push a blank gameState onto the game then discard it once chooseNewTargets has finalized the targets.

[Dilnu]

Actually that last solution works great now that I know bookmarks are a thing.

[Dilnu]

Welp... that doesn't really work either it just looked like it did in some circumstances.

To be more specific, if you bookmark and restore during an instance method of something stored in the game state then you're operating on an obsolete version of that object.

[JayDi85]

Try that tests:

    @Test
    public void BonecrusherGiantChangeTargets_BoneTargetBoth() {
        // Whenever Bonecrusher Giant becomes the target of a spell, Bonecrusher Giant deals 2 damage to that spell’s controller.
        addCard(Zone.BATTLEFIELD, playerA, "Bonecrusher Giant");
        //
        // Target creature gets +2/+2 until end of turn.
        // Conspire (As you cast this spell, you may tap two untapped creatures you control that share a color with it. When you do, copy it and you may choose a new target for the copy.)
        addCard(Zone.HAND, playerA, "Barkshell Blessing");
        addCard(Zone.BATTLEFIELD, playerA, "Plains");
        addCard(Zone.BATTLEFIELD, playerA, "Grizzly Bears");
        addCard(Zone.BATTLEFIELD, playerA, "Savannah Lions");

        castSpell(1, PhaseStep.UPKEEP, playerA, "Barkshell Blessing");
        setChoice(playerA, "Yes"); // use Conspire
        addTarget(playerA, "Bonecrusher Giant"); // target bone
        setChoice(playerA, "Grizzly Bears"); // pay for conspire
        setChoice(playerA, "Savannah Lions"); // pay for conspire
        setChoice(playerA, "No"); // both spells target bone
        setChoice(playerA, "When {this} becomes the target of a spell"); // two triggers

        setStrictChooseMode(true);
        setStopAt(1, PhaseStep.PRECOMBAT_MAIN);
        execute();
        assertAllCommandsUsed();

        assertPowerToughness(playerA, "Bonecrusher Giant", 4 + 2 * 2, 3 + 2 * 2);
        assertPowerToughness(playerA, "Grizzly Bears", 2, 2);
        assertPowerToughness(playerA, "Savannah Lions", 2, 1);
        assertLife(playerA, 20 - 2 * 2); // bone trigger from both spells
    }

    @Test
    public void BonecrusherGiantChangeTargets_BoneTargetFirst() {
        // Whenever Bonecrusher Giant becomes the target of a spell, Bonecrusher Giant deals 2 damage to that spell’s controller.
        addCard(Zone.BATTLEFIELD, playerA, "Bonecrusher Giant");
        //
        // Target creature gets +2/+2 until end of turn.
        // Conspire (As you cast this spell, you may tap two untapped creatures you control that share a color with it. When you do, copy it and you may choose a new target for the copy.)
        addCard(Zone.HAND, playerA, "Barkshell Blessing");
        addCard(Zone.BATTLEFIELD, playerA, "Plains");
        addCard(Zone.BATTLEFIELD, playerA, "Grizzly Bears");
        addCard(Zone.BATTLEFIELD, playerA, "Savannah Lions");

        castSpell(1, PhaseStep.UPKEEP, playerA, "Barkshell Blessing");
        setChoice(playerA, "Yes"); // use Conspire
        addTarget(playerA, "Bonecrusher Giant"); // target bone
        setChoice(playerA, "Grizzly Bears"); // pay for conspire
        setChoice(playerA, "Savannah Lions"); // pay for conspire
        setChoice(playerA, "Yes"); // new targt for copy: bear
        addTarget(playerA, "Grizzly Bears");

        setStrictChooseMode(true);
        setStopAt(1, PhaseStep.PRECOMBAT_MAIN);
        execute();
        assertAllCommandsUsed();

        assertPowerToughness(playerA, "Bonecrusher Giant", 4 + 2, 3 + 2);
        assertPowerToughness(playerA, "Grizzly Bears", 2 + 2, 2 + 2);
        assertPowerToughness(playerA, "Savannah Lions", 2, 1);
        assertLife(playerA, 20 - 2); // one trigger
    }

    @Test
    public void BonecrusherGiantChangeTargets_BoneTargetSecond() {
        // Whenever Bonecrusher Giant becomes the target of a spell, Bonecrusher Giant deals 2 damage to that spell’s controller.
        addCard(Zone.BATTLEFIELD, playerA, "Bonecrusher Giant");
        //
        // Target creature gets +2/+2 until end of turn.
        // Conspire (As you cast this spell, you may tap two untapped creatures you control that share a color with it. When you do, copy it and you may choose a new target for the copy.)
        addCard(Zone.HAND, playerA, "Barkshell Blessing");
        addCard(Zone.BATTLEFIELD, playerA, "Plains");
        addCard(Zone.BATTLEFIELD, playerA, "Grizzly Bears");
        addCard(Zone.BATTLEFIELD, playerA, "Savannah Lions");

        castSpell(1, PhaseStep.UPKEEP, playerA, "Barkshell Blessing");
        setChoice(playerA, "Yes"); // use Conspire
        addTarget(playerA, "Grizzly Bears"); // target bear
        setChoice(playerA, "Grizzly Bears"); // pay for conspire
        setChoice(playerA, "Savannah Lions"); // pay for conspire
        setChoice(playerA, "Yes"); // new target for copy: bone
        addTarget(playerA, "Bonecrusher Giant");
        // setChoice(playerA, "When {this} becomes the target of a spell"); // must be one trigger from bone, not two

        setStrictChooseMode(true);
        setStopAt(1, PhaseStep.PRECOMBAT_MAIN);
        execute();
        assertAllCommandsUsed();

        assertPowerToughness(playerA, "Bonecrusher Giant", 4 + 2, 3 + 2);
        assertPowerToughness(playerA, "Grizzly Bears", 2 + 2, 2 + 2);
        assertPowerToughness(playerA, "Savannah Lions", 2, 1);
        assertLife(playerA, 20 - 2); // one trigger
    }