mtg-online-drafter/docs/development/devlog/2024-12-18-190500_parsing_robustness.md

2024-12-18 - Parse Card Data Robustness

Problem

The user reported issues with "placing cards onto the battlefield". Specifically, this manifested in two likely ways:

1. Creature cards fading away instantly (dying to State-Based Actions) because their Power/Toughness was defaulted to 0/0.
2. Cards resolving to the Graveyard instead of Battlefield because the RulesEngine failed to identify them as Permanents (empty types array), defaulting to Instant/Sorcery behavior.

Root Cause

1. Missing P/T Passing: The server/index.ts file was constructing the initial game state from deck cards but failing to explicitly copy power and toughness properties.
2. Missing Type Parsing: The GameManager (and index.ts) relied on typeLine string but did not parse it into the types array which the RulesEngine strictly checks for isPermanent logic and invalid aura validation.

Solution

1. Updated GameManager.ts: Added robust parsing logic in addCardToGame. If card.types is empty, it now parses card.typeLine (e.g. splitting "Legendary Creature — Human") to populate types, supertypes, and subtypes arrays.
2. Updated server/index.ts: Modified all game initialization flows to explicitly pass power and toughness from the source data to gameManager.addCardToGame.

Outcome

Cards added to the game now have correct type metadata and base stats.

• Creatures resolve to the battlefield correctly (identified as Permanents).
• Creatures stay on the battlefield (Toughness > 0 prevents SBA death).