Pumpkin-MC/Pumpkin · error · PlayerDataError

NBT error

Error message

NBT error: {0}

What it means

Variant `Nbt` of `PlayerDataError` in pumpkin-world, carrying a `String` description. The library throws it when player data NBT parsing or writing fails — the stored `.dat` file is not valid NBT or contains unexpected fields when reading player state.

Solutions

1. Read the String payload for the specific NBT failure and inspect the .dat file
2. Restore the player's .dat from backup or delete it to reset the player's data
3. Verify the world's data version matches the running server

matches!(err, PlayerDataError::Nbt(_))

match storage.load_player_data(uuid) {
    Err(PlayerDataError::Nbt(msg)) => { warn!("corrupt playerdata for {uuid}: {msg}; resetting"); storage.reset(uuid)?; }
    other => other?,
}

When it happens

Trigger: Deserializing a player's `<uuid>.dat` file whose NBT structure is invalid, truncated, or written by an incompatible version.

Common situations: Corrupted playerdata from a server crash, playerdata copied between servers with different data versions, manually edited .dat files.

Understand the failure class

Background: "failed to unmarshal" / json.Unmarshal errors: why parsing a response into a Go struct fails and how to fix it — this error's family across 23 libraries.

Related errors

• Deserialization error
• Error deserializing chunk
• Failed reading chunk status
• Failed to decode varint - value too large
• Failed to decode varlong - value too large

AI-assisted analysis of Pumpkin-MC/Pumpkin@8d4639e25a (2026-09-09). Data as JSON: /api/errors/f3665d427208fc78. Report an issue: GitHub.

Appendix: source

Thrown at crates/pumpkin-world/src/data/player_data.rs:23

use tracing::{debug, error};
use uuid::Uuid;

/// Manages the storage and retrieval of player data from disk and memory cache.
///
/// This struct provides functions to load and save player data to/from NBT files,
/// with a memory cache to handle player disconnections temporarily.
pub struct PlayerDataStorage {
    /// Path to the directory where player data is stored
    data_path: PathBuf,
    /// Whether player data saving is enabled
    save_enabled: bool,
}

#[derive(Debug, thiserror::Error)]
pub enum PlayerDataError {
    #[error("IO error: {0}")]
    Io(#[from] io::Error),
    #[error("NBT error: {0}")]
    Nbt(String),
}

impl PlayerDataStorage {
    /// Creates a new `PlayerDataStorage` with the specified data path and cache expiration time.
    pub fn new(data_path: impl Into<PathBuf>, enabled: bool) -> Self {
        let path = data_path.into();
        if !path.exists()
            && let Err(e) = create_dir_all(&path)
        {
            error!(
                "Failed to create player data directory at {}: {e}",
                path.display()
            );
        }

        Self {
            data_path: path,

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