Fighting Game · Guides & deep dives

Mod Error Isolation

prevents the game from crashing, disables broken mods, quarantines disabled mods for review, and queues a player notification.

4sections1 minread
Markdown source
On this page

This document covers TODOS.phase-72.72.14.1.12: isolating broken mods so one mod panic or crash does not take down the game.

Runtime Surface#

  • module: V2Modding
  • policy: FV2ModErrorIsolationPolicy
  • runtime error: FV2ModRuntimeError
  • issue: FV2ModErrorIsolationIssue
  • action: FV2ModErrorIsolationAction
  • result: FV2ModErrorIsolationResult
  • helper functions: BuildDefaultModErrorIsolationPolicy, BuildModRuntimeError, EvaluateModErrorIsolation, BuildModErrorPlayerNotification, and ApplyModErrorIsolation
  • subsystem forwarding: UV2ModLoadingSubsystem::EvaluateErrorIsolation
  • automation: V2/ue/Source/V2Tests/Private/Modding/ModLoadingSystem.spec.cpp
  • contract: V2/ue/Content/V2/Modding/ModErrorIsolation_V2_Contract.json

Isolation Policy#

BuildDefaultModErrorIsolationPolicy catches mod panics, crashes, and timeouts, prevents the game from crashing, disables broken mods, quarantines disabled mods for review, and queues a player notification. Recoverable errors are allowed up to MaxRecoverableErrorsPerWindow before the mod is treated as broken.

Results#

EvaluateModErrorIsolation filters errors for the target mod, emits issues for caught panics, caught crashes, caught timeouts, and exceeded recoverable error budgets, then emits actions to continue the game, disable the mod, quarantine the mod, and notify the player as appropriate.

Player notification text is short and operational. It names the affected mod and states that the game is still running. ApplyModErrorIsolation preserves the protected-game state and ensures the notification remains available.

Verification#

bash
python3 V2/ue/Tools/check-v2-mod-error-isolation.py
python3 V2/ue/Tools/check-v2-mod-loading-system.py
python3 V2/ue/Tools/check-v2-ci-workflow.py
python3 V2/tools/validate-v2-docs.py
python3 -m py_compile V2/ue/Tools/check-v2-mod-error-isolation.py V2/ue/Tools/check-v2-mod-performance-profiling.py V2/ue/Tools/check-v2-ci-workflow.py
python3 -m json.tool V2/ue/Content/V2/Modding/ModErrorIsolation_V2_Contract.json