Please solve to the best of your ability explaining your reasoning in detail:
Absolutely. Here's a **difficult, exam-level undergraduate problem** focused on a **subtle, hard-to-track-down bug** in a Fire Emblem-style Godot 4 game clone. It emphasizes **debugging skills**, **engine internals understanding**, and **systematic problem-solving**, which are critical in real-world game development.

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## 🐞 Exam Question: Debugging a Phantom Double-Attack Bug in Godot 4 Tactical RPG

Your team is testing a near-complete build of your Fire Emblem-style game in **Godot 4**, and QA reports a mysterious bug:

> "Sometimes the combat forecast UI shows that a unit will double attack, but during actual combat, only one attack happens."

This bug appears **intermittently** and only for certain units. The problem seems more likely to occur:

* When the forecast is triggered immediately after moving a unit
* When skills that modify speed (like “Haste”) are involved
* On maps with many units (\~20+)

You are given the following:

* `Unit.gd`:

  ```gdscript
  func get_speed() -> int:
      var speed = base_speed
      for s in active_skills:
          speed += s.get_speed_bonus()
      return speed
  ```
* `CombatForecast.gd` calculates whether double attacks should happen:

  ```gdscript
  attacker_doubles = attacker.get_speed() >= defender.get_speed() + 4
  defender_doubles = defender.get_speed() >= attacker.get_speed() + 4
  ```
* The `GameManager.gd` handles movement, state transitions, and starts combat.
* The `SkillSystem.gd` manages passive and temporary buffs.

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### ❓ Part A: Bug Hypothesis (10 pts)

1. Propose **two plausible root causes** for the bug based on the symptoms and code structure. Address timing, state management, or data access issues.

2. Explain why this bug may appear **intermittently** and why it’s difficult to reproduce reliably.

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### ❓ Part B: Diagnostic Strategy (10 pts)

1. Describe a **systematic debugging approach** you would use to locate the actual source of the bug.

   * Include engine-specific techniques (e.g., signals, debugger, scene tree inspection).
   * Specify what logs, breakpoints, or test conditions you would set up.

2. How would you isolate whether the bug is due to **forecast logic** vs. **combat resolution** logic?

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### ❓ Part C: Engine Behavior and Timing (10 pts)

1. Explain how Godot’s **scene tree lifecycle (e.g., `_ready()`, `_process()`, deferred calls)** or **signal timing** might cause discrepancies between forecast and actual behavior.

2. What changes would you make to ensure consistency between what the player *sees* in the forecast and what actually happens during combat?

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### ❓ Part D: Long-Term Fix and Refactor (15 pts)

1. Propose an **architectural change** or design refactor to prevent this class of bug in the future (e.g., prediction mismatch due to shared state drift).

2. Explain how you'd enforce **consistency** between UI previews and game simulation outcomes. Suggest a strategy (e.g., shared simulation service, deterministic combat replay, immutable snapshot logic).

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## ✅ Grading Breakdown (Total: 45 pts)

| Part | Focus                                                     | Points |
| ---- | --------------------------------------------------------- | ------ |
| A    | Root cause analysis, bug intuition                        | 10     |
| B    | Debugging strategy, engine tooling                        | 10     |
| C    | Lifecycle/timing awareness, visual/simulation consistency | 10     |
| D    | Architectural robustness, future-proofing                 | 15     |

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### 🌟 Bonus (+2 pts)

Award for:

* Proposing automated testing hooks or snapshot diffs between forecast and resolution
* Integrating an internal combat log for players and developers to trace execution

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Would you like a **rubric** for this one too, or to package this in an editable/printable format?