onion-mc/analysis/archive/FTB-CHUNKS-SWAP.md

FTB Chunks -> Open Parties and Claims + Xaero's maps

Status: shipped - 2026-09-30 (1d02bf1, pushed). FTB Quests/Teams/XMod Compat removed after the swap; see section 8. Decision: replace FTB Chunks with Open Parties and Claims (OPAC) for claims/forceloading and Xaero's World Map + Minimap for mapping, and drop the rest of the FTB suite that depended on it. Remaining FTB mods: FTB Backups 3 and FTB Library only. Accepted cost: every player re-claims their land and re-creates their waypoints, and any FTB Quests content and per-team progress is discarded.

Confidence tags follow FINDINGS.md: VERIFIED / DOCUMENTED / COMMUNITY / INFERENCE.

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1. Why this works at all

The pack's earlier review (MODLIST-REVIEW.md §8) recommended keeping FTB Chunks on the grounds that "wholesale replacement breaks FTB Quests/Teams". That is only true of a wholesale FTB removal. VERIFIED: FTB Quests' build declares ftb-library + ftb-teams as required and ftb-xmod-compat as optional - not FTB Chunks. FTB Quests also ships no claim-chunk task type. So FTB Chunks is the one mod in the FTB suite that can leave without touching quests, provided Teams stays.

VERIFIED: nothing else in the pack declares FTB Chunks as a required dependency. The only cross-mod hooks are inside FTB XMod Compat (KubeJS/GameStages progression, rank-based claim limits), which degrade to inert modules.

2. What changed

Action	Path
Removed	mods/ftb-chunks-forge.pw.toml (was ftb-chunks-neoforge-2101.1.22, CF 314906)
Removed	config/ftbchunks-client.snbt (the minimap.enabled=true modpack default)
Edited	.packwizignore - dropped config/* + !config/ftbchunks-client.snbt, back to config/
Added	mods/open-parties-and-claims.pw.toml - neoforge-1.21.1-0.31.6 (side = "both")
Added	mods/xaeros-world-map.pw.toml - neoforge-1.21.1-1.46.0 (side = "both")
Added	mods/xaeros-minimap.pw.toml - neoforge-1.21.1-26.5.0 (side = "both")
Added	mods/xaeros-minimap-world-map-waystones-compatibility-forge.pw.toml - 2.1.0
Regenerated	index.toml (147 entries) and the [index] hash in pack.toml

Net: 146 mods (138 Modrinth/other + 8 CurseForge), down from 9 CurseForge-exclusive mods. All four new mods are Modrinth-hosted, so they are checkable by packwiz update.

The three Xaero's entries are byte-identical to the ones deleted in b0542f9 (2026-09-28) - same versions, same sha512s - so this is a revert of the map half of that commit, not a new integration.

3. Where the pack traded one thing for another

FTB Chunks capability	Replacement	Notes
Chunk claims + protection	OPAC	Server config now lives in the world save, not the pack.
Forceload + offline ticking	OPAC claims.forceload.offlineForceload	Farms-vs-TPS trade is unchanged; reliability is less proven (see §5).
Minimap + fullscreen map	Xaero's Minimap + World Map	Now two client mods instead of one.
Waypoints + teleport	Xaero's Minimap	No migration path - see §4.
Party/team claims	OPAC's built-in party system	FTB Teams was removed, so this is the only party system now. /oparties, /opm for party chat.
Waystones on the map	xaeros_waystones_compatibility	Restored; it had been removed with the maps.
FTB Ranks permission overrides	xaero.pac_max_claims / xaero.pac_max_forceloads	Moot in practice: FTB Ranks was never installed.

4. Migration runbook (server operator)

Before the update

1. Take a world backup. FTB Chunks' claim data stays in the save after the mod is removed, so this backup is the rollback path.
2. Have each player screenshot or export their FTB Chunks waypoints. They live client-side under local/ftbchunks/; there is no FTB Chunks -> Xaero's converter (only JourneyMap -> Xaero tools exist). Re-entry is manual.
3. Capture who owned which claims/forceloads, so players have a checklist and an admin can pre-claim using OPAC server-claim mode if desired.

Cutover (one update, low-activity window) 4. Do not run FTB Chunks and OPAC side by side - two claim systems means split protection logic. Hard cutover. 5. Start the server once with OPAC installed so it generates world/serverconfig/openpartiesandclaims-server.toml, then stop the server. 6. Edit the generated file (it carries # Default: comments for every key) and set at minimum:

• maxPlayerClaims = 500 (matches the old FTB Chunks cap)
• maxPlayerClaimForceloads = 25 (decided 2026-09-30; the stock default is lower, so leaving it alone silently removes forceloading)
• primaryPartySystem -> leave at the built-in default (FTB Teams is gone; do not point it at ftbteams)
• a decision on claims.forceload.offlineForceload (farms while offline vs TPS)
• add claims.forceload.offlineForceload to playerConfigurablePlayerConfigOptions / opConfigurablePlayerConfigOptions if players should be able to toggle their own

7. Re-claim: each player re-claims their base and re-forceloads, via the OPAC UI (') or the Xaero's world map (right-click / drag-select).

After 8. Verify per-player forceloading actually keeps chunks ticking with the owner offline. This is the known weak point (§5). 9. Verify protection across the modded stack - especially Create contraptions, Sable ships, and fake-player automation. 10. Re-tier any rank/permission limits you were relying on.

5. Risks and open items

• OPAC force-loading reliability is the one thing that can invalidate the swap. Open upstream issues report chunks marked forceloadable but never actually loaded (#855, #927, plus #237/#528). COMMUNITY. Test before trusting; re-test on every OPAC bump. If it fails, this swap should be rolled back - forceloading is the one feature the pack cannot work around.
• OPAC is self-described beta and releases frequently (0.31.6, 2026-09-10). DOCUMENTED.
• OPAC and Xaero's are version-coupled - OPAC's README tells users to keep the Xaero's mods on their latest versions. Bump them together.
• Claim protection parity is unverified. OPAC protects vanilla plus a supported-mod list (Create is built in on Forge), and needs manual exception entries for anything else. Open reports exist for creeper explosions (#731) and modded projectiles (#758) inside claims. COMMUNITY. The pack's Apotheosis/Sophisticated/Ars Nouveau/Alex's Mobs surface needs a pass.
• Sable / Create Aeronautics. A crash with Sable contraptions was reported (#873) and is closed, but was not re-verified against 0.31.6. COMMUNITY. Ships are not covered by plain chunk claims under either system; the pack has no ship-claim mod. Options if that matters: aeroclaims ("Create Aeronautics: Claims", NeoForge 1.21.1, works with OPAC or FTB), or sable-protect. Note that dropping FTB Chunks does close the door on ftbchunksaerospace and Create-Aeronautics-FTB-Chunks.
• Licensing. OPAC is LGPL-3.0 - no pack conditions. Xaero's World Map and Minimap are All Rights Reserved: because this pack is distributed from git.ljones.me and not from CurseForge/Modrinth, the terms require an easily accessible credit link to an official Xaero page in the pack. Add one. VERIFIED (from the mods' own "Modpacks and Other" sections).
• side = "both" for Xaero's puts them on the server too. That buys reliable multi-world map identity and server-side map profiles, and matches the pre-b0542f9 configuration, but the server then registers status effects that stop vanilla clients joining unless disabled in config/xaero/*. All players get mods via packwiz, so this is not expected to matter.
• Vanilla-client / optional-client is actually improved for claims: OPAC's client side is optional, so a player without it is still protected and can use /oclaims chat commands.

6. Rollback

Re-add mods/ftb-chunks-forge.pw.toml (and the client config if the minimap default is wanted) and packwiz refresh. FTB Chunks' claim/forceload data is untouched in the world save, so existing claims resume. Then remove OPAC and the Xaero's mods. Keep the pre-swap world backup regardless.

Note: rolling back the FTB Quests/Teams removal is a separate, larger job - re-adding them restores the mods but not any quest content or team progress that was discarded, unless <world>/ftbquests/ was archived first.

7. Follow-up: removing the rest of the FTB suite

Follow-on decision (2026-09-30): drop FTB Quests, FTB Teams and FTB XMod Compat as well, leaving only FTB Backups 3 and FTB Library.

Why FTB Teams could not go on its own - FTB Quests has a hard runtime dependency on it, not just a launcher one:

Evidence	Result
FTB-Quests@1.21.1/main build.gradle	requires('ftb-library-forge'), requires('ftb-teams-forge')
FTB Quests bytecode	references dev/ftb/mods/ftbteams/ in 14 classes, incl. FTBQuestsEventHandler
FTB Quests internals	TeamData class - quest progress is keyed per team

The mandatory = false in FTB's neoforge.mods.toml files is launcher metadata; the bytecode references are what actually break. FTB Quests also ships no claim-chunk task type, so nothing about claims depended on it.

Why XMod Compat went with it: its integrations were Quests/Chunks/Ranks plus JEI/KubeJS/LuckPerms bridges. With Quests and Chunks gone there is nothing left for it to bridge.

Why Library stayed: FTB Backups 3 uses FTB Library's config/UI classes (Panel, Theme, Widget, ConfigGroup, ConfigValue, SNBTCompoundTag) - 13 classes, and it does not bundle them, despite declaring only neoforge in its own metadata. Library in turn references dev/architectury in 47 classes, so Architectury API stays too.

Verified before removing: FTB Library and FTB Backups 3 reference ftbteams, ftbquests and ftbxmodcompat in 0 classes each, and nothing else in the pack references XMod Compat.

Consequences accepted: any authored FTB Quests content and per-team quest progress is discarded. There is no longer any party system to point OPAC at, so primaryPartySystem stays at OPAC's built-in default. The pack dropped from 9 to 5 CurseForge-sourced mods and from 149 to 146 mods.

8. Docs that need follow-up

• Map/waypoint rescue from the old FTB data - see analysis/FTB-XAERO-MAP-MIGRATION.md and the tools/ftbchunks-reveal.py + tools/prune-world-to-reveal.py scripts. Mask extraction is validated; the world-save pruning step is written and unit-tested but not yet run.

• FINDINGS.md - §3.3, §7.1, §8 rows 2-3, appendix A and appendix B updated in this change; §1's mod-count statistics were left at their earlier snapshot (a note was added).

• MODLIST-REVIEW.md §7.4 and §8 still say Open Parties and Claims is a SKIP/duplication and "Keep FTB". Stale - the swap is now the intended design.

• MODLIST-GROUPS.md / analysis/master-table.md / analysis/groups-table.md carry the same stale OPAC verdict.

• Not done: re-adding xaero-train-map (was Ov2r3aVY, 1.0.0). It is unblocked again by this change and the pack has Create trains; one-line addition if wanted.