fix(parser): bind a dig-from-among "that creature" shared-type reference to the trigger subject (Conjurer's Mantle #5900)

[rsnetworkinginc]

Summary

Fixes Conjurer's Mantle (#5900): its attack trigger — "Whenever equipped creature attacks, look at the top six cards of your library. You may reveal a card that shares a creature type with that creature from among them and put it into your hand." — never let you reveal a matching card, because the shared-creature-type filter matched nothing.

Root cause

Two layers of the same lost-context bug:

1. parse_dig_from_among parsed the "from among them" reveal filter with the ctx-free parse_target, so the enclosing trigger subject never reached the filter's parse_shared_quality_reference.
2. Even with the ctx in scope, parse_shared_quality_reference routed only the bare pronoun "it" through the ctx-aware resolve_pronoun_target; the singular demonstrative "that creature" fell through to the ctx-free parse_target, binding the shared-quality reference to ParentTarget.

In this attacks trigger there is no chosen target / recipient / effect-context object, so parent_target_shared_quality_values (game/filter.rs) returns None and the "shares a creature type" test matched no card — exactly the reported symptom (no card in the top six is ever selectable).

Sibling cards that reference the triggering creature with the pronoun "it" (Mana Echoes, the attacker anthem) already bind to TriggeringSource; only the demonstrative form in the dig-from-among reveal filter was missing.

Fix

• Thread the enclosing ParseContext through parse_dig_from_among so the reveal filter parses with the trigger subject in scope.
• Resolve the singular object demonstratives ("that creature" / "that permanent" / "that card") via the same resolve_pronoun_target path the bare pronoun "it" already used.

With a non-source trigger subject in scope the reference now binds to TriggeringSource (the attacking equipped creature); without one it stays ParentTarget, so non-trigger dig-from-among filters are unchanged. resolve_pronoun_target's existing subject discriminator (typed / AttachedTo subject → TriggeringSource; None / SelfRef / Any → ParentTarget) contains the blast radius to genuine trigger-subject contexts.

Tests (RED pre-fix / GREEN post-fix, verified via stash)

• conjurers_mantle_reveal_matches_shared_creature_type — drives the equipped Goblin's attack through the real combat + Dig reveal pipeline and asserts the shared-type Goblin card in the top six is selectable (empty pre-fix); non-creature fillers stay non-selectable; the revealed Goblin lands in hand.
• conjurers_mantle_shared_type_reference_binds_to_trigger_subject — parser guard pinning the reference to TriggeringSource (ParentTarget pre-fix).

CI parity (isolated CARGO_TARGET_DIR)

• cargo fmt --all -- --check — clean
• cargo clippy --workspace --exclude phase-tauri --all-targets --features engine/proptest -- -D warnings — clean
• cargo test -p engine --lib — 17565 passed, 0 failed
• cargo test -p engine --test integration — 3837 passed, 0 failed

Closes #5900

---

Model: claude-opus-4
Tier: Standard
Thinking: high

Gate A: PASS — cargo fmt --all -- --check, cargo clippy --workspace --exclude phase-tauri --all-targets --features engine/proptest -- -D warnings, cargo test -p engine --lib (17565 passed / 0 failed), and cargo test -p engine --test integration (3837 passed / 0 failed), all clean in an isolated CARGO_TARGET_DIR, pre- and post-rebase onto latest origin/main.

Anchored on:

• crates/engine/src/parser/oracle_effect/sequence.rs — parse_dig_from_among threads ParseContext and parses the "from among them" filter via parse_target_with_ctx.
• crates/engine/src/parser/oracle_target.rs — parse_shared_quality_reference routes the singular object demonstratives through the existing ctx-aware resolve_pronoun_target.
• crates/engine/src/game/filter.rs — parent_target_shared_quality_values / object_shares_quality_with_reference_filter (unchanged) resolve TriggeringSource from state.current_trigger_events (the AttackersDeclared event), which is why the trigger-subject binding is the correct seam.

Summary by CodeRabbit

• Bug Fixes

  • Improved interpretation of “from among them/those” filters so references resolve to the correct triggering object.
  • Added support for phrases such as “that creature,” “that permanent,” and “that card.”
  • Fixed card-selection behavior for effects like Conjurer’s Mantle, ensuring matching cards can be selected correctly.

• Tests

  • Added regression coverage for parsing and gameplay behavior involving creature-type filters and contextual references.

[coderabbitai]

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Review details

⚙️ Run configuration

Configuration used: Path: .coderabbit.yaml

Review profile: CHILL

Plan: Pro Plus

Run ID: b19e5c36-cadc-485c-8bc9-b4e834d5869a

📥 Commits

Reviewing files that changed from the base of the PR and between c74a32d and cd60822.

📒 Files selected for processing (2)

• crates/engine/src/parser/oracle_effect/sequence.rs
• crates/engine/src/parser/oracle_target.rs

📝 Walkthrough

Walkthrough

The parser now threads ParseContext through Dig-from-among filters and resolves singular demonstrative references such as “that creature” contextually. New Conjurer’s Mantle integration tests validate both parsed target binding and runtime card selection.

Changes

Conjurer’s Mantle parser fix

Layer / File(s)	Summary
Demonstrative target resolution crates/engine/src/parser/oracle_target.rs	Singular “that creature”, “that permanent”, and “that card” references now use context-aware pronoun resolution.
Context-aware Dig filter parsing crates/engine/src/parser/oracle_effect/sequence.rs, crates/engine/src/parser/oracle_effect/conditions.rs	Dig-from-among parsing accepts and propagates ParseContext, allowing “from among” filters to resolve references against the enclosing parse state.
Conjurer’s Mantle regression coverage crates/engine/tests/integration/issue_5900_conjurers_mantle.rs, crates/engine/tests/integration/main.rs	Runtime and parser tests verify matching creature cards are selectable and that “that creature” binds to the triggering source.

Estimated code review effort: 3 (Moderate) | ~20 minutes

Suggested labels: bug

Suggested reviewers: matthewevans, lgray, andriypolanski

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Linked Issues check	✅ Passed	The changes address #5900 by making the dig-from-among filter context-aware and adding regression tests for Conjurer's Mantle.
Out of Scope Changes check	✅ Passed	The PR stays focused on the reported parsing bug and supporting tests, with no unrelated changes evident.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly matches the main fix: context-aware parsing of a shared-type reference in Dig-from-among for Conjurer's Mantle #5900.

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

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[coderabbitai]

🧹 Nitpick comments (2)

crates/engine/src/parser/oracle_target.rs (1)

6163-6178: 🎯 Functional Correctness | 🔵 Trivial | ⚡ Quick win

Missing "that token" demonstrative variant.

The loop covers "that creature", "that permanent", "that card" but omits "that token". The sibling anaphora combinator in crates/engine/src/parser/oracle_effect/counter.rs (counter_anaphor_created_token_binding) already treats "that token"/"the token"/"the permanent" as part of the same demonstrative family for an analogous binding, suggesting "that token" is a real Oracle form for shared-quality references (e.g. "a card that shares a card type with that token") that this arm would currently miss and fall through to the generic parse_target path.

Suggested fix

-    for demonstrative in ["that creature", "that permanent", "that card"] {
+    for demonstrative in ["that creature", "that permanent", "that card", "that token"] {

🤖 Prompt for AI Agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

In `@crates/engine/src/parser/oracle_target.rs` around lines 6163 - 6178, Extend
the demonstrative list in the pronoun-resolution loop around
resolve_pronoun_target to include “that token”. Preserve the existing ctx-aware
binding and fallback behavior for the other singular demonstratives.

crates/engine/src/parser/oracle_effect/sequence.rs (1)

5275-5291: 📐 Maintainability & Code Quality | 🔵 Trivial | ⚡ Quick win

Duplicate filter-resolution block across both from among branches.

Both the "milled this way" branch and the "from among them/those" branch carry an identical empty/"card"/"cards"/"of them" guard plus the same multi-line CR-cited parse_target_with_ctx call and comment. This is the same class of duplication that caused issue #5900 (one branch had drifted to ctx-free parse_target while the other used parse_target_with_ctx). Extracting a small shared helper would make the two branches structurally impossible to desync again.

Suggested extraction

+fn resolve_dig_from_among_filter_text(filter_text: &str, ctx: &mut ParseContext) -> TargetFilter {
+    if filter_text.is_empty()
+        || filter_text == "card"
+        || filter_text == "cards"
+        || filter_text == "of them"
+    {
+        return TargetFilter::Any;
+    }
+    // CR 608.2c + CR 608.2k: parse the "from among them" reveal/put filter
+    // with the enclosing ctx so an anaphoric reference inside it binds to
+    // the trigger subject (`TriggeringSource`) when one exists (`#5900`).
+    let (parsed_filter, _) = parse_target_with_ctx(filter_text, ctx);
+    parsed_filter
+}

Then both call sites become let filter = resolve_dig_from_among_filter_text(filter_text, ctx);.

Also applies to: 5382-5398

🤖 Prompt for AI Agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

In `@crates/engine/src/parser/oracle_effect/sequence.rs` around lines 5275 - 5291,
Extract the duplicated filter-resolution logic from both “milled this way” and
“from among them/those” branches into a shared helper such as
resolve_dig_from_among_filter_text, preserving the empty/“card”/“cards”/“of
them” handling and ctx-aware parse_target_with_ctx behavior. Replace both local
blocks with calls to the helper, passing filter_text and ctx.

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Nitpick comments:
In `@crates/engine/src/parser/oracle_effect/sequence.rs`:
- Around line 5275-5291: Extract the duplicated filter-resolution logic from
both “milled this way” and “from among them/those” branches into a shared helper
such as resolve_dig_from_among_filter_text, preserving the
empty/“card”/“cards”/“of them” handling and ctx-aware parse_target_with_ctx
behavior. Replace both local blocks with calls to the helper, passing
filter_text and ctx.

In `@crates/engine/src/parser/oracle_target.rs`:
- Around line 6163-6178: Extend the demonstrative list in the pronoun-resolution
loop around resolve_pronoun_target to include “that token”. Preserve the
existing ctx-aware binding and fallback behavior for the other singular
demonstratives.

---

ℹ️ Review info

⚙️ Run configuration

Configuration used: Path: .coderabbit.yaml

Review profile: CHILL

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📥 Commits

Reviewing files that changed from the base of the PR and between c3824d2 and c74a32d.

📒 Files selected for processing (5)

• crates/engine/src/parser/oracle_effect/conditions.rs
• crates/engine/src/parser/oracle_effect/sequence.rs
• crates/engine/src/parser/oracle_target.rs
• crates/engine/tests/integration/issue_5900_conjurers_mantle.rs
• crates/engine/tests/integration/main.rs

[github-actions]

Parse changes introduced by this PR

✓ No card-parse changes detected.

[matthewevans]

Approved: current-head parser context propagation uses the established target parser, and the registered combat-to-Dig regression is discriminating.