ship/t157 l1 library

[matthewevans]

• refactor(engine): route effect-owned library placement through the zone pipeline (L1)
• chore: tighten zone-authority baseline after L1 library-placement migration

[gemini-code-assist]

Code Review

This pull request refactors library-placement effects (Cascade, Discover, Ripple, and PutAtLibraryPosition) to route through the replacement-aware library-placement pipeline, ensuring that resolution and completion events wait for randomized placements to settle under CR 616.1 and CR 401.4. It introduces several new BatchCompletion variants to handle these deferred completions. The review feedback correctly identifies a violation of Rule R6, pointing out that the newly added batch completion handlers in run_batch_completion lack mandatory CR annotations.

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[gemini-code-assist]

[HIGH] Missing mandatory CR annotations for rules-touching batch completion handlers. Evidence: crates/engine/src/game/engine_resolution_choices.rs:5394-5463.

Why it matters: Under Rule R6 of the phase.rs style guide, every rules-touching line of engine code must carry a comment of the form CR <number>: <description> to ensure strict fidelity to the Magic Comprehensive Rules. When moving the cascade, discover, and top-placement completion logic to run_batch_completion, the original CR annotations (such as CR 406.6 for dropping exile links) were omitted.

Suggested fix: Add the verified CR annotations to each match arm in run_batch_completion.

        BatchCompletion::CascadeBottomComplete {
            controller,
            source_id,
            exiled_count,
        } => {
            // CR 702.85a: A no-hit Cascade's randomized bottom batch has settled, so its completion events may fire.
            events.push(GameEvent::CascadeMissed {
                controller,
                source_id,
                exiled_count,
            });
            events.push(GameEvent::EffectResolved {
                kind: EffectKind::Cascade,
                source_id,
                subject: None,
            });
        }
        BatchCompletion::DiscoverBottomComplete { source_id } => {
            // CR 701.57a: A no-hit Discover's randomized bottom batch has settled, so the discover resolution completes.
            events.push(GameEvent::EffectResolved {
                kind: EffectKind::Discover,
                source_id,
                subject: None,
            });
        }
        BatchCompletion::DiscoverPlacementComplete { source_id } => {
            // CR 701.57a: A Discover that found a card has finished placing every miss after its cast/hand decision.
            events.push(GameEvent::EffectResolved {
                kind: EffectKind::Discover,
                source_id,
                subject: None,
            });
        }
        BatchCompletion::DiscoverDeclined {
            player,
            hit_card,
            source_id,
        } => {
            // CR 701.57a: A declined Discover's miss batch settled; move the hit card to hand.
            zones::move_to_zone(state, hit_card, Zone::Hand, events);
            events.push(GameEvent::EffectResolved {
                kind: EffectKind::Discover,
                source_id,
                subject: None,
            });
            finish_with_continuation(state, player, events);
        }
        BatchCompletion::ResolutionCastRejectedToHand {
            player,
            hit_card,
            source_id,
        } => {
            // CR 608.2g / CR 701.57a: A Discover cast rejected at finalization waits for the miss batch before its hit-to-hand instruction.
            zones::move_to_zone(state, hit_card, Zone::Hand, events);
            events.push(GameEvent::EffectResolved {
                kind: EffectKind::Discover,
                source_id,
                subject: None,
            });
            crate::game::priority::clear_priority_passes(state);
            state.waiting_for = WaitingFor::Priority { player };
        }
        BatchCompletion::PutOnTopComplete {
            source_id,
            removed_exile_links,
        } => {
            // CR 406.6: The exiled cards left the exile zone — drop their source links.
            state.exile_links.retain(|link| {
                link.source_id != source_id || !removed_exile_links.contains(&link.exiled_id)
            });
            events.push(GameEvent::EffectResolved {
                kind: EffectKind::PutAtLibraryPosition,
                source_id,
                subject: None,
            });
        }

References

1. Every rules-touching line of engine code must carry a comment of the form CR : (regex CR \d{3}(.\d+[a-z]?)?). ^(link)
2. Avoid omitting mandatory CR annotations on rules-touching code blocks to maintain strict fidelity to the Magic Comprehensive Rules.

[github-actions]

Parse changes introduced by this PR

✓ No card-parse changes detected.