Fighting Game · Guides & deep dives

V2 Platform Cloud Save Sync

reads a newer cloud save when local state is clean.

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Phase 72.21.1.10 adds the public platform cloud-save sync surface for auto-syncing save files, reading cloud saves, writing local saves to platform cloud storage, and resolving conflicts through the existing persistence conflict UI. FV2PlatformCloudSaveSyncPolicy owns provider coverage, FV2PlatformCloudSaveFileState describes local and cloud revisions, and FV2PlatformCloudSaveSyncPlan carries the platform SDK request plan.

Operations#

PlanPlatformCloudSaveSync supports:

  • AutoSyncSaveFile writes dirty local saves to platform cloud storage, or reads a newer cloud save when local state is clean.
  • ReadCloudSave queues EV2PlatformSdkRequestType::ReadCloudSave through the platform SDK abstraction.
  • WriteCloudSave queues EV2PlatformSdkRequestType::WriteCloudSave with a payload hash and payload byte count.
  • ResolveCloudConflict queues UseCloud as a cloud read and UseLocal or MergeLedgers as a cloud write after persistence accepts the final action.

Conflicts are not resolved inside V2OnlineServices. Divergent local/cloud state blocks platform API calls and routes to the persistence conflict screen Save.CloudConflictResolution, backed by cloud policy CloudSave.OnlineServices.V2 in V2/ue/Content/V2/Persistence/Profile/ProfileSaveGame_V2_Contract.json.

Provider Routes#

Provider Native storage surface Read command Write command Conflict command
Steamworks ISteamRemoteStorage ISteamRemoteStorage::FileRead ISteamRemoteStorage::FileWrite ISteamRemoteStorage::FilePersisted
Epic Online Services EOS_PlayerDataStorage EOS_PlayerDataStorage_ReadFile EOS_PlayerDataStorage_WriteFile EOS_PlayerDataStorage_DuplicateFile
GOG Galaxy galaxy::api::IStorage galaxy::api::IStorage::FileRead galaxy::api::IStorage::FileWrite galaxy::api::IStorage::FileDelete
PlayStation SDK V2PlayStationSavedDataInterface PsnSavedData.Read PsnSavedData.Write PsnSavedData.ResolveConflict
Xbox GDK V2XboxGdkConnectedStorageInterface XboxConnectedStorage.Read XboxConnectedStorage.Write XboxConnectedStorage.ResolveConflict

Console routes stay public stubs in V2OnlineServices. Proprietary PlayStation and Xbox headers or symbols stay in restricted platform SDK modules.

Rules#

The default policy requires Steamworks, EOS, GOG Galaxy, PlayStation SDK, and Xbox GDK route coverage. Every route must support auto-sync, reads, writes, conflict callbacks, atomic writes, persistence conflict delegation, and per-platform user namespaces. Platform API failures fail closed; offline requests queue retry metadata but do not call native storage until the provider API is reachable.

Auto-sync requires cloud sync to be enabled, a linked platform account, a valid save slot, and a local or cloud save. Writes require payload metadata. Reads require a cloud save. Unaccepted conflicts report CloudSaveConflict and block native calls until persistence returns UseLocal, UseCloud, or MergeLedgers.

Verification#

Run:

bash
python3 V2/ue/Tools/check-v2-platform-cloud-save-sync.py

The checker validates the C++ API, contract, automation spec, CI workflow, Horde gate, documentation, and TODO evidence for Section 72.21.1.10.