Pocketmine-mp: Written_Book created with NBT tags crashes client

[JUSTaMod]

Issue description

Creating a written book in NBT with /give, then having a player attempt to open said book, will crash the client.

example - /give usernamehere written_book 1 {title:"Book Title",author:"Author Name",pages:["Page 1"]}

• Expected result: Open the book, see the pages and text.
• Actual result: Client crashed.

Steps to reproduce the issue

1. run the command provided in the issue description.
2. Open the book.

OS and versions

• Server Versions: PocketMine-MP 3.0.5 for Minecraft: PE v1.4.0 (protocol version 261)
  PocketMine-MP 4.0.0+dev.1236 for Minecraft: PE v1.4.0 (protocol version 261)
• PHP: 7.2.5
• Server OS: Windows Server Datacenter, version 1803 build 17134
• Game version: PE/Win10 (this bug applies to both - aren't they technically the same now anyway???)

Plugins

• Tested on a clean server without plugins. Check.

Crashdump, backtrace or other files

The feedback to the server is simply - userhere -- logged out due to timeout

[dktapps]

You've structured the NBT incorrectly. See https://github.com/pmmp/PocketMine-MP/blob/master/src/pocketmine/item/WritableBook.php#L114 for an example.

[JUSTaMod]

Got it.

[lukeeey]

Shouldn't the server check the structure to prevent these crashes in the future?

[ZizzyZizzy]

Java version server allows the same command to be used without issue. Book doesn't crash the client though.

Go ahead, shoot yourself in the foot, apparently.

[dktapps]

There's no end of special cases that will crash the client. I have no more intention of taping over this one than any other. This is Mojang's issue to fix.