replay-validation-workflow

name	replay-validation-workflow
description	Operational runbook for validating deterministic replay integrity across schema updates and gameplay code changes.
tier	operational
godot_version	4.6+
doc_anchors	["godot-docs/tutorials/io/saving_games.rst","godot-docs/tutorials/io/runtime_file_loading_and_saving.rst","godot-docs/tutorials/editor/command_line_tutorial.rst","godot-docs/tutorials/scripting/debug/overview_of_debugging_tools.rst"]
tags	["replay","determinism","validation"]
depends_on	["godot-skills/godot-tertiary/deterministic-save-replay-io-schema/SKILL.md","godot-skills/godot-operational/qa-validation-loop/SKILL.md"]

Replay Validation Workflow

Use When

• Replay/event-log generation or loader code changes.
• Deterministic gameplay state transitions are modified.
• Schema migrations affect replay payloads.

Outcomes

• Replays reproduce identical authoritative results on repeat execution.
• Replay fixtures from supported historical versions still validate.
• Divergence points are isolated to exact action/tick boundaries.

Required Rules

• Validate replay determinism from the same initial snapshot and intent log.
• Compare deterministic boundaries (tick/commit/hash), not visual-only outcomes.
• Keep replay fixture corpus versioned with explicit expected outcomes.
• Fail fast on first divergence and persist trace context for debugging.

Workflow

1. Select representative replay fixtures (happy path, edge case, migration case).
2. Run each fixture once to capture baseline outcome hashes/commit boundaries.
3. Re-run fixtures in identical runtime conditions and compare boundaries.
4. If divergence appears, bisect to first differing action/tick and capture payload context.
5. Update fixtures only when schema evolution is intentional and migration checks pass.

Validation

• Deterministic run pair: same fixture run twice yields identical final hash.
• Migration run: older fixture upgrades and replays to expected current outcome.
• Failure drill: inject malformed replay event and verify explicit, safe rejection.

Failure Modes

• Replay logs include non-deterministic presentation state.
• Fixture corpus lacks edge cases, allowing regressions to slip through.
• Migration updates fixtures without preserving backward compatibility evidence.

Local Doc Anchors

• godot-docs/tutorials/io/saving_games.rst
• godot-docs/tutorials/io/runtime_file_loading_and_saving.rst
• godot-docs/tutorials/editor/command_line_tutorial.rst
• godot-docs/tutorials/scripting/debug/overview_of_debugging_tools.rst