PocketMine-MP/changelogs/3.4.md

**For Minecraft: Bedrock Edition 1.7.0**

This is a cumulative minor release featuring performance improvements, memory usage improvements, some new minor gameplay features, some API deprecations and additions, and significant changes to error handling.

### Note
Plugins compatible with any previous 3.x.y version will also run on these releases and do not need API bumps.

However, some API features have been deprecated in this version. Plugin developers do not need to do anything about these deprecations immediately, however they may raise harmless warnings if used.

Features marked **`@deprecated`** are **recommended** not to be used, but will continue to work for any future 3.x.y versions. They will be removed in the next major release (4.0).

# 3.4.0
## Core changes
### Performance & memory improvements
- Entity `EXHAUSTION` attribute is no longer synced to the client, which reduces network traffic for survival players and reduces client-sided lag.
- A redundant call was removed from an `Event` call hot path which improves event calling performance by ~15% per event handler executed.
- Light updates are now batched together and executed on the end of each tick. The effects of this are noticeable when setting a large number of blocks in a close area - significant performance improvements should be noticeable for world editors (the ones that didn't disable light updates) and liquid flow is now significantly less expensive.
- Internal enhancements have been made to subchunk light array interfacing to reduce branching and improve access performance.
- Memory usage of most chunks has dropped by ~30-40% due to some improvements to internal storage of unlit subchunks. In real terms this translates to ~30% memory usage reduction for a freshly generated world.

### Error handling
The most notable core change in this release revolves around error handling. Internals have been cleaned up substantially to improve the server behaviour under occurrence of unexpected behaviour. The goal of this is to improve consistency and quality while reducing undefined runtime behaviour.
The following changes have been made:
- Throwing **unexpected** `Throwable`s in the following cases will now cause a server crash (except on network (this will be changed in the future)):
  - Event handlers
  - `Task->onRun()` on a scheduler
  - `AsyncTask->onCompletion()`
  - `Command->execute()` and `CommandExecutor->onCommand()`
- Unexpected `Throwable`s thrown during packet handling will now cause the target player to be disconnected with an `Internal server error` message.

### Other changes
- Anti-flight has been removed, along with the `allow-flight` directive in `server.properties`.
- Server language is now controlled by the `language` directive in `server.properties`.
- Added `unban` and `unban-ip` as aliases of `pardon` and `pardon-ip` commands respectively.

## API changes
### Block
- `BlockSpreadEvent` is now fired when lava or water tries to flow into a block.
- `BlockFormEvent` is now fired when lava and water collide to form cobblestone, obsidian or stone.

### Event
- Added new method `Event->call()`. This should be used instead of `PluginManager->callEvent()` in plugins only supporting 3.4+.
- `PluginManager->callEvent()` has been `@deprecated`.

### Level
- Attempting to unload a level during its tick will now throw an `InvalidStateException`.
- Added the following new methods:
  - `Level->broadcastPacketToViewers()`
  - `Level->getViewersForPosition()`
  - `Level->broadcastGlobalPacket()`
  - `Level->getChunkAtPosition()`
  - `Level->isInLoadedTerrain()`
- `Level->addGlobalPacket()` has been `@deprecated`.
- `LightUpdate` now allows calling `setAndUpdateLight()` for the same position multiple times (needed for light update batching).

### Permission
- `Permission::getByName()` now throws an exception on invalid values instead of silently returning `DEFAULT_FALSE`. This may cause new errors to appear if your plugins had broken permission defaults in `plugin.yml`.

### Player
- `addWindow()` now has stricter validity checks and will now throw exceptions in the following cases: No window IDs left to use, and when a forced window ID collides with an existing window.
- The public `$speed` field has been removed (this was only used by anti-cheat which has now been removed).

### Scheduler
- `AsyncTask->setResult()` has had the `$serialize` parameter removed - now it will automatically serialize (or not) as appropriate.
- Added a new `ClosureTask` which allows concisely scheduling closure execution on a `TaskScheduler`.
- `TaskScheduler->__construct()` `$logger` parameter has been `@deprecated` and will be removed in a future major version.

### Server
- Added new method `Server->hasOfflinePlayerData(string $name) : bool`.
- `Server->getAllowFlight()` has been `@deprecated`.

### Utils
- `Config->save()` will no longer catch unexpected exceptions thrown while encoding data.

## Gameplay changes
### Blocks
- Rail connectivity has been implemented for normal, powered, detector and activator rails (but there are currently no minecarts).

# 3.4.1
- Updated crashdump format to be compatible with newest CA. This version or newer is required if you want to be able to submit crashdumps to crash.pmmp.io.

# 3.4.2
- `DataPacket` errors when writing to undefined fields are now more clear.
- Fixed trees being able to overwrite the log parts of other trees.
- Fixed `Player->sendForm()` not working during `PlayerJoinEvent`.
- `Entity->setScale()` now explicitly requires a scale larger than 0.
- Adding invisible `FloatingTextParticle` to a level no longer causes an error.

# 3.4.3
- Fixed burning TNT setting hurt entities on fire when exploding.
- `~` relative coordinates now work in the `/particle` command.
- Various boring fixes to error stack trace reporting.
- `Level->setChunk()` no longer deletes tiles and entities when replacing a chunk with itself.
- Fixed a generator race condition causing rare appearances of half-trees on the client in freshly generated terrain.
- `Attribute->resetToDefault()` now fits the default per the min/max bounds, fixing crashes when the bounds are changed to exclude the default.
- Fixed a crash with LevelDB worlds when the `TAG_2D_MAPS` tag is missing.
- Fixed `Utils::getCoreCount()` crashing on some Debian variants.