fix(replay): re-apply server wire blanking of clanTag/friends when replaying

[evanpelle]

Problem

Team games played with disableClanTags or anonymizeNames desync the moment a replay starts, with a desync error on every hash checkpoint.

Live clients never simulate with players' real clanTag/friends under those settings: the server blanks them identically for every client (GameServer.start() wireGameStartInfo / startInfoFor()), because both fields feed deterministic team assignment (TeamAssignment.ts). The archived record intentionally keeps the real values (analytics ingest reads them), and replays rebuild GameStartInfo straight from record.info — so the replay derives a different team split than every live client did, diverges at the first cross-team interaction, and mismatches every recorded hash from then on.

(FFA is unaffected — those modes never run team assignment, which is why public FFA records replay fine despite disableClanTags: true.)

Fix

Re-apply the server's blanking at replay time instead of stripping the archive:

• src/core/Util.ts — new toWireGameStartInfo(), mirroring the server's rules: disableClanTags → every clanTag nulled; anonymizeNames → clanTag nulled and friends dropped. Returns the info untouched when neither flag is set.
• src/client/Main.ts — the replay path (lobby.gameRecord.info → gameStartInfo) passes through the helper. Live games are unaffected: their start info arrives from the server already blanked, so the transform is a no-op there by construction.
• tests/replay/ReplayGame.ts — the headless harness applies the same transform, so npm run replay:game verifies records exactly the way the client replays them.

Singleplayer records are exempt: those games simulate and archive without a server, so their real values are the simulation inputs — blanking them would introduce a new desync.

Tests

• New tests/ToWireGameStartInfo.test.ts: blanking under each flag, the identity fast-path, the singleplayer exemption, and input non-mutation.
• tsc --noEmit clean, lint clean; TeamAssignment/Team/ArchivePlayerRecord/ArchivedRecordSchema suites pass.

Notes

• Applies to any record that archived the real values — i.e. everything since fix(server): preserve teamIndex, friends, isLobbyCreator in archived game records #4819 preserved friends/teamIndex. Pre-fix(server): preserve teamIndex, friends, isLobbyCreator in archived game records #4819 records remain unreplayable (fields were never stored), same as before.
• Sibling of fix(server): preserve teamIndex, friends, isLobbyCreator in archived game records #4819 (teamIndex) and fix(tribes): carry custom tribe names into the archived game record #4854 (tribes): third case of a live-simulation input not surviving the record → replay round trip.

🤖 Generated with Claude Code

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No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro Plus

Run ID: 56ecfe78-7a10-499d-b91f-2b8d81623314

📥 Commits

Reviewing files that changed from the base of the PR and between 9daa0c2 and c4ba9f8.

📒 Files selected for processing (4)

• src/client/Main.ts
• src/core/Util.ts
• tests/ToWireGameStartInfo.test.ts
• tests/replay/ReplayGame.ts

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Walkthrough

toWireGameStartInfo now sanitizes multiplayer game-start data. Client lobby joins and replay construction use the sanitized data. Tests cover masking, passthrough behavior, preserved identity fields, and input immutability.

Changes

Game start wire sanitization

Layer / File(s)	Summary
Wire-format transformation and tests src/core/Util.ts, tests/ToWireGameStartInfo.test.ts	Adds toWireGameStartInfo. It blanks clan tags when configured and removes friends during name anonymization. Tests cover passthrough cases and immutability.
Client and replay integration src/client/Main.ts, tests/replay/ReplayGame.ts	Client joins and replay construction convert archived game-start data before delivery. Explicit lobby data remains preferred.

Estimated code review effort: 2 (Simple) | ~15 minutes

Sequence Diagram(s)

sequenceDiagram
  participant ReplayGame
  participant Main.handleJoinLobby
  participant toWireGameStartInfo
  participant joinLobby
  ReplayGame->>toWireGameStartInfo: Convert replay game-start data
  toWireGameStartInfo-->>ReplayGame: Return sanitized data
  Main.handleJoinLobby->>toWireGameStartInfo: Convert archived replay data
  toWireGameStartInfo-->>Main.handleJoinLobby: Return sanitized data
  Main.handleJoinLobby->>joinLobby: Pass explicit or sanitized start info

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Possibly related PRs

• openfrontio/OpenFrontIO#4759: Both changes sanitize GameStartInfo before exposure.
• openfrontio/OpenFrontIO#4819: Both changes modify replay game-start handling.

Suggested reviewers: celant, ryanbarlow97, variablevince

Poem

Game starts cross the wire,
Clan tags fade when rules require.
Friends stay hidden, fields stay true,
Replays share the same view.
Clean data travels through.

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly identifies the replay fix and the affected clanTag and friends wire blanking behavior.
Description check	✅ Passed	The description accurately explains the replay desynchronization, the wire blanking fix, affected paths, exemptions, and tests.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

✨ Finishing Touches 💡 1

🛠️ Fix failing CI checks 💡

• Create stacked PR
• Commit on current branch

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