Holograms not working on 1.16.4

[TheAwoo]

The issue

Created shops display no holograms whatsoever. Still able to buy/sell; player balance changes properly.

PaperMC version: paper-1.16.5-428

Plugin version: Build #99

Hologram format config:

lines:
  0:
    options:
      normal-shop:
        format: "%VENDOR%"
        requirements:
          - NORMAL_SHOP

      admin-shop:
        format: "&cAdmin Shop"
        requirements:
          - ADMIN_SHOP

  1:
    options:
      default:
        format: "%AMOUNT% x %ITEMNAME%"
        requirements:

  2:
    options:
      buy-and-sell:
        format: "Buy %BUY-PRICE% | %SELL-PRICE% Sell"
        requirements:
          - BUY_PRICE > 0
          - SELL_PRICE > 0

      only-buy:
        format: "Buy %BUY-PRICE%"
        requirements:
          - BUY_PRICE > 0

      only-sell:
        format: "Sell %SELL-PRICE%"
        requirements:
          - SELL_PRICE > 0

Relevant logs:

> shop reload
[14:02:29 INFO]: [ShopChest] Using locale "en_US"
[14:02:29 INFO]: [de.epiceric.shopchest.dependencies.hikari.HikariDataSource] HikariPool-1 - Shutdown initiated...
[14:02:29 INFO]: [de.epiceric.shopchest.dependencies.hikari.HikariDataSource] HikariPool-1 - Shutdown completed.
[14:02:29 INFO]: [de.epiceric.shopchest.dependencies.hikari.HikariDataSource] HikariPool-2 - Starting...
[14:02:29 INFO]: [de.epiceric.shopchest.dependencies.hikari.HikariDataSource] HikariPool-2 - Start completed.
[14:02:29 INFO]: [ShopChest] Cleaned up economy log
[14:02:29 INFO]: Successfully reloaded 1 shop/s.
[14:02:29 WARN]: Exception in thread "pool-29-thread-3" java.lang.NullPointerException
[14:02:29 WARN]:        at java.base/java.lang.String.replace(String.java:2158)
[14:02:29 WARN]:        at de.epiceric.shopchest.shop.Shop.getHologramText(Shop.java:317)
[14:02:29 WARN]:        at de.epiceric.shopchest.shop.Shop.createHologram(Shop.java:228)
[14:02:29 WARN]:        at de.epiceric.shopchest.shop.Shop.lambda$create$1(Shop.java:141)
[14:02:29 WARN]:        at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1130)
[14:02:29 WARN]:        at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:630)
[14:02:29 WARN]:        at java.base/java.lang.Thread.run(Thread.java:832)

on using a shop

[14:06:44 ERROR]: Could not pass event PlayerInteractEvent to ShopChest v1.13-SNAPSHOT
java.lang.NullPointerException: null
        at java.lang.String.replace(String.java:2158) ~[?:?]
        at de.epiceric.shopchest.language.LanguageUtils.getMessage(LanguageUtils.java:2666) ~[?:?]
        at de.epiceric.shopchest.listeners.ShopInteractListener.buy(ShopInteractListener.java:874) ~[?:?]
        at de.epiceric.shopchest.listeners.ShopInteractListener.handleInteractEvent(ShopInteractListener.java:285) ~[?:?]
        at de.epiceric.shopchest.listeners.ShopInteractListener.onPlayerInteract(ShopInteractListener.java:471) ~[?:?]
        at com.destroystokyo.paper.event.executor.asm.generated.GeneratedEventExecutor389.execute(Unknown Source) ~[?:?]
        at org.bukkit.plugin.EventExecutor.lambda$create$1(EventExecutor.java:69) ~[patched_1.16.5.jar:git-Paper-428]
        at co.aikar.timings.TimedEventExecutor.execute(TimedEventExecutor.java:80) ~[patched_1.16.5.jar:git-Paper-428]
        at org.bukkit.plugin.RegisteredListener.callEvent(RegisteredListener.java:70) ~[patched_1.16.5.jar:git-Paper-428]
        at org.bukkit.plugin.SimplePluginManager.callEvent(SimplePluginManager.java:607) ~[patched_1.16.5.jar:git-Paper-428]
        at org.bukkit.craftbukkit.v1_16_R3.event.CraftEventFactory.callPlayerInteractEvent(CraftEventFactory.java:510) ~[patched_1.16.5.jar:git-Paper-428]
        at net.minecraft.server.v1_16_R3.PlayerInteractManager.a(PlayerInteractManager.java:464) ~[patched_1.16.5.jar:git-Paper-428]
        at net.minecraft.server.v1_16_R3.PlayerConnection.a(PlayerConnection.java:1549) ~[patched_1.16.5.jar:git-Paper-428]
        at net.minecraft.server.v1_16_R3.PacketPlayInUseItem.a(PacketPlayInUseItem.java:27) ~[patched_1.16.5.jar:git-Paper-428]
        at net.minecraft.server.v1_16_R3.PacketPlayInUseItem.a(PacketPlayInUseItem.java:5) ~[patched_1.16.5.jar:git-Paper-428]
        at net.minecraft.server.v1_16_R3.PlayerConnectionUtils.lambda$ensureMainThread$1(PlayerConnectionUtils.java:23) ~[patched_1.16.5.jar:git-Paper-428]
        at net.minecraft.server.v1_16_R3.TickTask.run(SourceFile:18) ~[patched_1.16.5.jar:git-Paper-428]
        at net.minecraft.server.v1_16_R3.IAsyncTaskHandler.executeTask(IAsyncTaskHandler.java:136) ~[patched_1.16.5.jar:git-Paper-428]
        at net.minecraft.server.v1_16_R3.IAsyncTaskHandlerReentrant.executeTask(SourceFile:23) ~[patched_1.16.5.jar:git-Paper-428]
        at net.minecraft.server.v1_16_R3.IAsyncTaskHandler.executeNext(IAsyncTaskHandler.java:109) ~[patched_1.16.5.jar:git-Paper-428]
        at net.minecraft.server.v1_16_R3.MinecraftServer.bb(MinecraftServer.java:1132) ~[patched_1.16.5.jar:git-Paper-428]
        at net.minecraft.server.v1_16_R3.MinecraftServer.executeNext(MinecraftServer.java:1125) ~[patched_1.16.5.jar:git-Paper-428]
        at net.minecraft.server.v1_16_R3.IAsyncTaskHandler.awaitTasks(IAsyncTaskHandler.java:119) ~[patched_1.16.5.jar:git-Paper-428]
        at net.minecraft.server.v1_16_R3.MinecraftServer.sleepForTick(MinecraftServer.java:1086) ~[patched_1.16.5.jar:git-Paper-428]
        at net.minecraft.server.v1_16_R3.MinecraftServer.w(MinecraftServer.java:1000) ~[patched_1.16.5.jar:git-Paper-428]
        at net.minecraft.server.v1_16_R3.MinecraftServer.lambda$a$0(MinecraftServer.java:173) ~[patched_1.16.5.jar:git-Paper-428]
        at java.lang.Thread.run(Thread.java:832) [?:?]

[TheAwoo]

Update

Managed to debug and reproduce the issue on my end. As it turns out, some economy plugins do not provide a meaningful implementation of Economy.format(double) and instead just return null.

That, in turn, causes the following code to throw on a null value:

switch (placeholder) {
    case BUY_PRICE:
        replace = plugin.getEconomy().format(getBuyPrice()); // sets replace to null
        break;
    case SELL_PRICE:
        replace = plugin.getEconomy().format(getSellPrice()); // also sets replace to null
        break;
    default:
        replace = String.valueOf(placeholders.get(placeholder));
}

format = format.replace(placeholder.toString(), replace); // consumes the null and throws

Despite the issue being caused by incomplete implementations of Economy in other plugins I'd still recommend handling this case more gracefully, perhaps even printing out a message to nag the authors of used econ plugin to provide a proper format implementation.