hytale-f2p-mirror/docs/UUID_BUGS_FIX_PLAN.md

UUID/Skin Reset Bug Fix Plan

Problem Summary

Players experience random skin/cosmetic resets without intentionally changing anything. The root cause is that the UUID system has multiple failure points that can silently generate new UUIDs or use the wrong UUID during gameplay.

Impact: Players lose their customized cosmetics/skins randomly, causing frustration and confusion.

Status: ✅ FIXED - All critical and high priority bugs have been addressed.

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Implementation Summary

What Was Fixed

Bug	Severity	Status	Description
BUG-001	Critical	✅ Fixed	Username not loaded before play click
BUG-002	High	✅ Fixed	isFirstLaunch() always returns true
BUG-003	Critical	✅ Fixed	Silent config corruption returns empty object
BUG-004	Critical	✅ Fixed	Non-atomic config writes
BUG-005	High	✅ Fixed	Username fallback to 'Player'
BUG-006	Medium	✅ Fixed	Launch overwrites username every time
BUG-007	Medium	✅ Fixed	Dual UUID systems (playerManager vs config)
BUG-008	High	✅ Fixed	Error returns random UUID
BUG-009	Medium	✅ Fixed	Username case sensitivity
BUG-010	Medium	⏳ Pending	Migration marks complete on partial failure
BUG-011	Medium	⏳ Pending	Race condition on concurrent config access
BUG-012	High	✅ Fixed	UUID modal isCurrent flag broken
BUG-013	High	✅ Fixed	UUID setting uses unsaved DOM username
BUG-014	Medium	✅ Fixed	No way to switch between saved identities
BUG-015	High	✅ Fixed	installGame saves username (overwrites good value)
BUG-016	High	✅ Fixed	Username rename creates new UUID instead of preserving
BUG-017	Medium	✅ Fixed	UUID list not refreshing when player name changes
BUG-018	Low	✅ Fixed	Custom UUID input doesn't allow copy/paste

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User Scenario Analysis

All user scenarios have been analyzed for UUID/username persistence:

Scenario	Risk	Status	Details
Fresh Install	Low	✅ Safe	firstLaunch.js reads but doesn't modify username/UUID
Username Change	Low	✅ Safe	Rename preserves UUID, user-initiated saves work correctly
Auto-Update	Low	✅ Safe	Config is on disk before update, backup recovery available
Manual Update	Low	✅ Safe	Config file persists across manual updates
Different Install Location	Low	✅ Safe	Config uses central app directory, not install-relative
Repair Game	Low	✅ Safe	repairGame() doesn't touch config
UUID Modal	Low	✅ Fixed	Fixed isCurrent badge, unsaved username bug, added switch button
Profile Switch	Low	✅ Safe	Profiles only control mods/java, not username/UUID
Branch Change	Low	✅ Safe	Only changes game version, not identity

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Files Modified

File	Changes
backend/core/config.js	Atomic writes, backup/recovery, validation, case-insensitive UUID lookup, checkLaunchReady(), username rename preserves UUID
backend/managers/gameLauncher.js	Pre-launch validation, removed saveUsername call
backend/managers/gameManager.js	Removed saveUsername call from installGame
backend/services/playerManager.js	Marked DEPRECATED, throws on error, retry logic
backend/launcher.js	Export new functions (checkLaunchReady, hasUsername, etc.)
GUI/js/launcher.js	Uses checkLaunchReady API, blocks launch if no username
GUI/js/settings.js	UUID modal fixes, switchToUsername function, proper error handling, refreshes UUID list on name change
GUI/style.css	Switch button styling, user-select: text for UUID input
GUI/locales/*.json	Added translation keys for switch username functionality (all 10 locales)
main.js	Fixed UUID IPC handlers, added checkLaunchReady handler, enabled Ctrl+V/C/X/A shortcuts
preload.js	Exposed checkLaunchReady to renderer

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Bug Categories

Category A: Race Conditions & Initialization

Category B: Silent Failures & Fallbacks

Category C: Data Integrity & Persistence

Category D: Design Issues

Category E: UI/UX Issues

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Detailed Bug List & Fixes

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BUG-001: Username Not Loaded Before Play Click (CRITICAL) ✅ FIXED

Category: A - Race Condition

Location:

• GUI/js/launcher.js
• GUI/js/settings.js

Problem: If user clicks Play before settings DOM initializes, returns 'Player' silently.

Fix Applied:

• launcher.js now uses checkLaunchReady() API to validate before launch
• Loads username from backend config (single source of truth)
• Blocks launch and shows error if no username configured
• Navigates user to settings page to set username

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BUG-002: isFirstLaunch() Always Returns True (HIGH) ✅ FIXED

Category: B - Silent Failure

Location: backend/core/config.js

Problem: Function always returns true even when user has data (typo: return true instead of return false).

Fix Applied:

• Fixed return statement: return true → return false

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BUG-003: Silent Config Corruption Returns Empty Object (CRITICAL) ✅ FIXED

Category: B - Silent Failure

Location: backend/core/config.js

Problem: Corrupted config silently returns {}, causing UUID regeneration.

Fix Applied:

• Added config validation after load
• Implemented backup config system (config.json.bak)
• Tries loading backup if primary fails
• Logs detailed errors for debugging

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BUG-004: Non-Atomic Config Writes (CRITICAL) ✅ FIXED

Category: C - Data Integrity

Location: backend/core/config.js

Problem: Direct write can corrupt file if interrupted. Silent error logging.

Fix Applied:

• Atomic write: write to temp file → verify JSON → backup current → rename
• Throws error on save failure (no silent continuation)
• Cleans up temp file on failure

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BUG-005: Username Fallback to 'Player' (HIGH) ✅ FIXED

Category: B - Silent Failure

Location: backend/core/config.js

Problem: Missing username silently falls back to 'Player', causing wrong UUID.

Fix Applied:

• loadUsername() returns null instead of 'Player'
• Added loadUsernameWithDefault() for display purposes
• Added hasUsername() helper function
• All callers updated to handle null case explicitly

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BUG-006: Launch Overwrites Username Every Time (MEDIUM) ✅ FIXED

Category: D - Design Issue

Location: backend/managers/gameLauncher.js

Problem: If playerName parameter is wrong, it overwrites the saved username.

Fix Applied:

• Removed saveUsername() call from launch process
• Username only saved when user explicitly changes it in Settings
• Launch loads username from config (single source of truth)

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BUG-007: Dual UUID Systems (playerManager vs config) (MEDIUM) ✅ FIXED

Category: D - Design Issue

Location:

• backend/services/playerManager.js → player_id.json
• backend/core/config.js → config.json → userUuids

Problem: Two independent UUID systems can desync.

Fix Applied:

• playerManager.js marked as DEPRECATED
• All code uses config.js getUuidForUser()
• Migration function added for legacy player_id.json

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BUG-008: Error Returns Random UUID (HIGH) ✅ FIXED

Category: B - Silent Failure

Location: backend/services/playerManager.js

Problem: Any error generates random UUID, losing player identity.

Fix Applied:

• Now throws error instead of returning random UUID
• Retry logic added (3 attempts before failure)
• Caller must handle the error appropriately

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BUG-009: Username Case Sensitivity (MEDIUM) ✅ FIXED

Category: D - Design Issue

Location: backend/core/config.js

Problem: "PlayerOne" and "playerone" are different UUIDs.

Fix Applied:

• getUuidForUser() uses case-insensitive lookup
• Username stored with ORIGINAL case (preserves "Sanasol", "SaAnAsOl", etc.)
• Lookup normalized to lowercase for matching
• Case changes update the stored key while preserving UUID

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BUG-010: Migration Marks Complete Even on Partial Failure (MEDIUM) ⏳ PENDING

Category: C - Data Integrity

Location: backend/utils/userDataMigration.js

Problem: Partial copy is marked as complete, preventing retry.

Status: Not yet implemented - low priority since migration runs once.

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BUG-011: Race Condition on Concurrent Config Access (MEDIUM) ⏳ PENDING

Category: A - Race Condition

Location: backend/core/config.js

Problem: No file locking - concurrent processes can overwrite each other.

Status: Not yet implemented - would require proper-lockfile package. Low risk since launcher is single-instance.

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BUG-012: UUID Modal isCurrent Flag Broken (HIGH) ✅ FIXED

Category: D - Design Issue

Location: main.js - get-all-uuid-mappings IPC handler

Problem: Case-sensitive comparison between normalized key (lowercase) and current username.

// BROKEN:
isCurrent: username === loadUsername()  // "player1" === "Player1" → FALSE

Fix Applied:

• IPC handler now uses getAllUuidMappingsArray() from config.js
• This function correctly compares against normalized username

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BUG-013: UUID Setting Uses Unsaved DOM Username (HIGH) ✅ FIXED

Category: B - Silent Failure

Location: GUI/js/settings.js - performSetCustomUuid()

Problem: Gets username from DOM input field instead of saved config.

// BROKEN:
const username = getCurrentPlayerName();  // From UI input, not saved!

Risk Scenario: User types new name but doesn't save → opens UUID modal → sets custom UUID → UUID gets set for unsaved name while config has old name.

Fix Applied:

• Now loads username from backend config via window.electronAPI.loadUsername()
• Shows error if no username is saved

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BUG-014: No Way to Switch Between Saved Identities (MEDIUM) ✅ FIXED

Category: D - Design Issue

Location: GUI/js/settings.js - UUID modal

Problem: UUID modal showed list of usernames/UUIDs but no way to switch to a different identity.

Fix Applied:

• Added switchToUsername() function
• New switch button (user-check icon) on non-current entries
• Confirmation dialog before switching
• Updates username input and refreshes UUID display

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BUG-015: installGame Saves Username (HIGH) ✅ FIXED

Category: D - Design Issue

Location: backend/managers/gameManager.js - installGame()

Problem: saveUsername(playerName) call could overwrite good username with 'Player' default.

Fix Applied:

• Removed saveUsername() call from installGame()
• Username only saved when user explicitly changes it in Settings

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BUG-016: Username Rename Creates New UUID (HIGH) ✅ FIXED

Category: D - Design Issue

Location: backend/core/config.js - saveUsername()

Problem: When user changes their player name, a new UUID was generated instead of preserving the existing one. User's identity (cosmetics/skins) was lost on every name change.

Symptom: Change "Player1" to "NewPlayer" → gets completely new UUID → loses all cosmetics.

Fix Applied:

• saveUsername() now handles UUID mapping renames atomically
• When renaming: old username's UUID is moved to new username
• When switching to existing identity: uses that identity's existing UUID
• Case changes only: updates key casing, preserves UUID
• Both username and userUuids saved in single atomic operation

Behavior After Fix:

// Rename: "Player1" → "NewPlayer"
// Before: Player1=uuid-123, NewPlayer=uuid-NEW (wrong!)
// After:  NewPlayer=uuid-123 (same UUID, just renamed)

// Switch to existing: "Player1" → "ExistingPlayer"
// Uses ExistingPlayer's existing UUID (switching identity)

// Case change: "Player1" → "PLAYER1"
// UUID preserved, key updated to new case

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BUG-017: UUID List Not Refreshing on Name Change (MEDIUM) ✅ FIXED

Category: E - UI/UX Issue

Location: GUI/js/settings.js - savePlayerName()

Problem: After changing player name in settings, the UUID modal list didn't refresh. The "Current" badge showed on the old username instead of the new one.

Fix Applied:

• Added await loadAllUuids() call after loadCurrentUuid() in savePlayerName()
• UUID modal now shows correct "Current" badge after name changes

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BUG-018: Custom UUID Input Doesn't Allow Copy/Paste (LOW) ✅ FIXED

Category: E - UI/UX Issue

Location: GUI/style.css, main.js

Problem: Two issues prevented copy/paste:

1. The body element has select-none class (Tailwind) which applies user-select: none globally
2. Electron's setIgnoreMenuShortcuts(true) was blocking Ctrl+V/C/X/A shortcuts

Fix Applied:

• Added user-select: text with all vendor prefixes to .uuid-input class
• Removed setIgnoreMenuShortcuts(true) from main.js
• Added early return in before-input-event handler to allow Ctrl/Cmd + V/C/X/A shortcuts
• DevTools shortcuts (Ctrl+Shift+I/J/C, F12) remain blocked

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Translation Keys Added

The following translation keys were added to GUI/locales/en.json:

{
  "notifications": {
    "noUsername": "No username configured. Please save your username first.",
    "switchUsernameSuccess": "Switched to \"{username}\" successfully!",
    "switchUsernameFailed": "Failed to switch username",
    "playerNameTooLong": "Player name must be 16 characters or less"
  },
  "confirm": {
    "switchUsernameTitle": "Switch Identity",
    "switchUsernameMessage": "Switch to username \"{username}\"? This will change your current player identity.",
    "switchUsernameButton": "Switch"
  }
}

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Testing Checklist

After implementing fixes, verify:

• Launch with freshly installed launcher - UUID persists
• Change username in settings - UUID preserved (renamed, not new)
• Config corruption - recovers from backup
• Click Play immediately after opening - correct UUID used
• Manual update from GitHub - UUID persists
• Username with different casing - same UUID used, case preserved
• UUID modal shows correct "Current" badge
• UUID modal refreshes after username change
• Switch identity from UUID modal works
• Profile switching doesn't affect username/UUID
• Custom UUID input allows copy/paste

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Architecture: How UUID/Username Persistence Works

Config Structure (config.json):

{
  "username": "CurrentPlayer",
  "userUuids": {
    "Sanasol": "uuid-123-abc",
    "SaAnAsOl": "uuid-456-def",
    "Player1": "uuid-789-ghi"
  },
  "hasLaunchedBefore": true
}

Key Design Decisions:

• Username stored with ORIGINAL case (e.g., "Sanasol", "SaAnAsOl")
• UUID lookup is case-insensitive (normalized to lowercase for matching)
• Username rename preserves UUID (atomic rename operation)
• Profile switching does NOT affect username/UUID (shared globally)
• All config writes use atomic pattern: temp file → verify → backup → rename
• Automatic backup recovery if config corruption detected

Data Flow:

1. User sets username in Settings → saveUsername() handles rename logic → saves to config.json
2. If renaming: UUID moved from old name to new name (same UUID preserved)
3. Launch game → checkLaunchReady() validates username exists
4. Launch game → getUuidForUser(username) gets UUID (case-insensitive lookup)
5. UUID modal → shows all username→UUID mappings from config
6. Switch identity → saves new username → gets that username's UUID

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Success Criteria

• ✅ Zero silent UUID regeneration
• ✅ Config corruption recovery working
• ✅ No UUID change without explicit user action
• ✅ Username rename preserves UUID
• ✅ Username case is preserved in display
• ✅ UUID modal correctly identifies current user
• ✅ UUID modal refreshes on changes
• ✅ Users can switch between saved identities
• ✅ Copy/paste works in UUID input

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Remaining Work

1. BUG-010: Verify migration completeness before marking done (low priority)
2. BUG-011: Add file locking with proper-lockfile (low priority - single instance)
3. Add telemetry for config load failures and UUID regeneration events

Completed Additional Tasks

• ✅ Added translation keys to all 10 locale files (de-DE, es-ES, fr-FR, id-ID, pl-PL, pt-BR, ru-RU, sv-SE, tr-TR, en)