Resin trim gets stripped from armor when interacting on pre-resin server (1.20.1)

[mfishma]

'/viaversion dump' Output

https://dump.viaversion.com/a005fcce82bf6cb0120aaff11c804b45d14789a2795ce8ad40775609a7d9106c

Server/Client Error

(no errors)

Bug Description

I was looking into #1330 and wanted to see current behavior, but noticed the problem of trim being lost going back to the server when playing on pre-1.21.4 (when resin was introduced). Any resin armor trim I give myself (used an anvil to be sure) loses its trim once I go to the old client, move the item around, then return on the new client.

Steps to Reproduce

1. On a modern server (26.3), make any armor piece with a resin trim. (This doesn't happen with other trims)
2. Connect to the server using a Minecraft 1.20.1 client.
3. Open inventory, equip the trimmed armor, and take it off (or move it between slots).
4. Disconnect and rejoin using a modern client (26.3).

Expected

• Resin armor trim component should be preserved across client-to-server inventory packets (CONTAINER_CLICK / SET_CREATIVE_SLOT).
• Going back to the modern server, the armor should still have its resin trim.

Actual

• The trim data is stripped from the item on the server after being moved in the 1.20.1 inventory.
• When viewed on modern server, the armor's now untrimmed.

Additional Server Info

I noticed EntityPacketRewriter1_20_5 writes to user.get(ArmorTrimStorage.class), while updateArmorTrim reads from user.storables(Protocol1_20_3To1_20_5.class).armorTrims() which just has the hardcoded 1.20.3 defaults. Should it be updating the storables instance instead?

Checklist

• Via plugins are only running on EITHER the backend servers (e.g. Paper) OR the proxy (e.g. Velocity), not on both.
• I have included a ViaVersion dump.
• If applicable, I have included a paste (not a screenshot) of the error.
• I have tried a build from https://ci.viaversion.com/ and the issue still persists.

[Barvalg]

[roccodev]

It seems to rather be an issue with tag -> component translation, it only affects < 1.20.5 (for example 1.21.2 doesn't have resin but isn't affected).

You can also reproduce it with missing trim patterns, a diamond trim material paired with the Flow trim pattern (added in 1.20.5) also breaks