Tab completion breaks randomly after a while.

Expected behavior

Tabbing commands should work no problem.

Observed/Actual behavior

When the player joins, they can use command tab completion just fine, but after a few minutes it seems to break randomly

It seems from packet logging, the client IS being sent tab completion packets, but refusing to show them:

S2C
TAB_COMPLETE
[a(int):0],
[b(com.mojang.brigadier.suggestion.Suggestions):Suggestions{range=StringRange{start=7, end=7}, suggestions=[Suggestion{range=StringRange{start=7, end=7}, text='test1', tooltip='null'}, Suggestion{range=StringRange{start=7, end=7}, text='test2', tooltip='null'}]}]

Also, the transaction id sent by the vanilla 1.20.2 client always seems to be zero,

C2S
TAB_COMPLETE [a(int):0],[b(java.lang.String):/test te],

which makes no sense. Yet tab completion does function for the first few minutes of being online with this zero id.

Steps/models to reproduce

public class Test implements TabExecutor {

@Override
public boolean onCommand(CommandSender sender, Command command, String label, String[] args) {
    return true;
}

@Override
public List<String> onTabComplete(CommandSender sender, Command arg1, String arg2, String[] args) {
    return List.of("test1","test2");
}

}

Paper version

This server is running Paper version git-Paper-"f613437" (MC: 1.20.2) (Implementing API version 1.20.2-R0.1-SNAPSHOT) (Git: f613437)
You are running the latest version
Previous version: git-Paper-"a2ba452" (MC: 1.20.2)

Other

No response

Looking at MCP this behaviour makes no sense, it should be incrementing the transaction id:

public CompletableFuture<Suggestions> customSuggestion(CommandContext<?> p_212423_) {
      if (this.pendingSuggestionsFuture != null) {
         this.pendingSuggestionsFuture.cancel(false);
      }

      this.pendingSuggestionsFuture = new CompletableFuture<>();
      int i = ++this.pendingSuggestionsId;
      this.connection.send(new ServerboundCommandSuggestionPacket(i, p_212423_.getInput()));
      return this.pendingSuggestionsFuture;
   }

wtf?

[electronicboy]

the id is reset when it gets a matching response, race condition? er 🤷

damn, I cannot replicate the issue if I test on a paper server with just 1 plugin. Could my use of packet events and protocollib in another plugin be causing this?

[lynxplay]

I mean, potentially ? Not being able to replicate this on a plain server does point in the direction of a plugin.
Can you please try to narrow down which plugin might be causing this, e.g. via binary search ?

Replication steps would be a requirement for us to keep this issue open 😅

It is confirmed to be caused by packetevents, but I don't know how it could be happening, it could be because I'm using both protocol lib and packet events within the same plugin.

…

On Fri, 13 Oct 2023, 13:41 Bjarne Koll, ***@***.***> wrote: I mean, potentially ? Not being able to replicate this on a plain server does point in the direction of a plugin. Can you please try to narrow down which plugin might be causing this, e.g. via binary search <https://docs.papermc.io/paper/basic-troubleshooting#binary-search> ? Replication steps would be a requirement for us to keep this issue open 😅 — Reply to this email directly, view it on GitHub <#9832 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/BCOULXI257ZNCADBXQJ2IR3X7EZH3AVCNFSM6AAAAAA56J7AICVHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHMYTONRRGQ2TIMJWGY> . You are receiving this because you authored the thread.Message ID: ***@***.***>

[electronicboy]

Just listening in the event pipeline will have 0 implications, if those break it it's going to be down to some interactions on the packets or whatever, but, not our avenue