[MC-148454] Villager trade GUI shows incorrect price when a discount is applied on servers

The bug

On servers, all players (on LAN servers, all players except the host) get displayed an incorrect price for discounted trades. Instead of the original price being displayed crossed out and the discounted price standing next to it, the discounted price is crossed out and an incorrect price stands next to it (that price being the original price discounted twice).

This is how it looks to the host of a LAN world / to the server:

[media]

This is how it looks to all the other players:

[media]

To reproduce

by @unknown

Create a new singleplayer world (superflat for convenience, creative).
Summon on a safe spot a villager, assign him the mason profession by placing down a stonecutter.
Open the world to you LAN and let a second account join.
Give the hero of the village status effect to both players:
```
/effect give @a hero_of_the_village 999 1 true
```
Try to trade with the mason one account, then the other.
❌ The guest account is displaying the incorrect price

Video

[media]

Original report

Server side inventories do not apply the advertised price, instead applying the original full price. This is applicable to both buy and sell trades. If the world is copied to saves folder and played as a single player world, the proper price will be applied to the trade.

How to produce:
1. Download server jar file from most recent patch notes page.
2. Create server.
3. Trade with villagers on server.

Side Note: This bug also affects Realms servers.

Linked issues

is cloned by 1

MC-151282 Villager trade GUI doesn't show the correct price on servers if trade demand is high Resolved

is duplicated by 40

MC-10809 Hearts from breeding animals appear "behind" water and ice Resolved

MC-147225 Villager trade shows wrong prices Resolved

MC-147971 Villagers do not show the real discount with effect "Hero of the village" Resolved

MC-148333 Villager UI destroying trade items when multi-trading Resolved

MC-148803 Villager Trade reverses after closing trade screen Resolved

35 more links

relates to 1

MC-145698 Villager trades do not lock in dedicated servers Resolved

Attachments

Server VIllager Trading.mp4

Comments 25

Johnibur 2019-04-16T19:52:36Z

Can confirm.
You should update the title for more visibility, something like: "Villager trades do no apply discount on dedicated servers".

Trevor Koenig 2019-04-16T20:22:57Z

Great Idea! If you don't mind I'm going to use your title.

Johnibur 2019-04-18T21:41:06Z

Can confirm for 1.14-pre5.

Johnibur 2019-04-24T11:48:55Z

Can confirm for 1.14.

Jerozgen 2019-04-24T12:06:21Z

Villager trades do apply discount, but it is displayed wrongly. Trade cost is (original_price - x), but it displayed as (original_price - x - x).

15 more comments

Johnibur 2019-04-24T13:00:27Z

Indeed, this is my testing trade:

[media]

You can see it is displayed as selling 8 clay instead of 9, but after doing some research I found that the normal trade is 10 and remains the same for all mason. So what happens is the price slot is replaced by the discounted price, and the discounted slot is replaced by the discounted price applied twice. Also makes sense with the trades on the attached video.
Please update this ticket accordingly: Villager trade GUI shows incorrect price when a discount is applied on dedicated server.

David Lee Barrett 2019-04-24T23:37:22Z

Confirming this bug is also present on Realms servers, took awhile to figure out I had to pay the not-full-full price.

Tom MacDevitt 2019-04-26T19:41:40Z

What I've found is that the discounted price is used for buying gear, but only if the player has at least as many emeralds as the original. I had the hero affect, and I could buy gear that normally cost 11 for 1, but only of I had 11 emeralds.

Jeremy Currier 2019-04-26T22:10:28Z

I had this bug on Pre-Release 5. Made an entire raid farm just to be disappointed that the trades weren't being discounted server side. Although, I haven't had any issues with this on a fresh, 1.14 world, indicating this might be a converting issue.

wally 2019-04-27T06:12:18Z

Playing on a fresh world. This bug affects my server as well

Laura Bergman 2019-04-27T11:03:52Z

This also happens on our Realms world, huge bummer.

Johnibur 2019-04-27T11:06:48Z

Reproduction steps on a new world open to LAN and 2 accounts

With the first account, the "host", create a new singleplayer world (superflat for convenience, creative).
Summon on a safe spot a villager, assign him the mason profession by placing down a stonecutter.
Open the world to your LAN and join with a second account, the "client".
Give the hero of the village status effect to both players:
```
/effect give @a hero_of_the_village 999 1 true
```
Try to trade with the mason with the host, then with the client.

-> The host account (the one playing on "integrated server") has the correct trade displaying:

[media]

-> The client account (the one playing on "vanilla server") who joined the world has the incorrect trade displaying:

[media]

We can see the prices are just shifted by one extra discount operation. In both cases, the villager will only accept the price as displayed to the host account.

No Thanks 2019-04-29T20:32:42Z

I believe the hero of the village effect is just to get the discounted trades quicker rather than trading with them. I don't know if my bug is the same or not. see MC-149880

Trevor Koenig 2019-04-30T03:32:20Z

From what I can tell, it seems as though the server is only sending the discounted price to the client account, which is being confused as the full price, and thus the discount is applied twice. This obviously would be fixed by either sending both prices to the client or just the full price and the discount factor. I may be wrong though.

To No Thanks,
it seems as though your bug is different although possibly related, with again the client side of the game being confused as the what the server side is actually doing.

Jackson Trexler 2019-05-01T01:12:59Z

I was wondering what was causing this! Had this exact same issue except on a friend group realm.

lettuceshoes 2019-05-02T04:27:39Z

Can confirm on my friends 1.14 Release realm

Nino de Vriend 2019-05-02T13:38:24Z

I have this problem too on my realm

Brian Santos da Fonseca 2019-05-05T02:21:44Z

This bug can also be seen in this video, in 2:25, when he trades emeralds for the chestplate that shows 1 emerald as cost but gets 5 emeralds deducted instead -> https://www.youtube.com/watch?v=poK7CzjWsGM

I'm hoping it gets fixed soon, it can be really misleading, completely broken display

Anqing Chen 2019-05-09T15:17:06Z

I'm not sure how to re-open this, but this is still NOT resolved in 1.14.1 pre-1, see MC-151282

Trevor Koenig 2019-05-09T16:01:13Z

Anqing, is that in pre-release 1, or 2? I cannot currently test this and would like to not incorrectly mark affected versions.

violine1101 2019-05-09T16:09:13Z

I cannot reproduce this in 1.14.1-pre1 and assumed that the 1.14.1-pre1 being added to affected versions in MC-151282 was a mistake. @unknown, if you want your ticket to be reopened, please leave a comment on that ticket.

Trevor Koenig 2019-05-10T00:06:43Z

I also was unable to reproduce this in 1.14.1-pre2, The trades and their GUIs are working on my dedicated server.

violine1101 2019-05-10T15:07:06Z

The same issue still exists, but only for villagers that previously were zombie villagers and have been cured. See MC-151282.

Nick 2019-05-12T05:50:33Z

Still A Major Problem, Mods no help marking everything resolved.

violine1101 2019-05-12T09:23:53Z

@unknown, this particular issue has been fixed in 1.14.1 Pre-Release 1, though a similar issue still exists. A report about that issue, MC-151282, is still left open.