Solved My plugin doesn't load and it don't show any error

Yours haven't player $player

 

You’re correct! Now delete that and there you go, a working onCommand function!

 

Thank you. The plugin loads with Devtools but the command function doesn't work

 

Did you write down the commands in the plugin.yml folder?

 

Yes here:
-------------------------------------------------------------
name: JoinLeave
version: 1.1.0
main: JoinLeave\Main
api: [3.0.0, 4.0.0]
author: GeistFan
command:
tjl:
description: Testet ob JoinLeave aktiv ist.
permission: JoinLeaveTest.cmd

permissons:
JoinLeaveTest.cmd:
default: op
description: Darf /tjl benutzen.
-------------------------------------------------------------
-GeistFan

 

YAML is space sensitive, by pasting it here it completely dismantled it. Next time try using code blocks or pastebin.

The issue is that the command key must be in plural, check this example plugin https://github.com/pmmp/ExamplePlugin/blob/master/plugin.yml

TL;DR add 's' to 'command' key

 

Now the command says the message but when i use the command the server crash
-GeistFan

 

Good, now it would be helpful if you posted here the crash message.

 

PocketMine-MP Crash Dump Fri Mar 26 19:37:29 GMT 2021

Error: Return value of JoinLeave\Main:nCommand() must be of the type bool, none returned
File: plugins/JoinLeave-1.1.1/src/JoinLeave/Main
Line: 42
Type: TypeError

THIS CRASH WAS CAUSED BY A PLUGIN
BAD PLUGIN: JoinLeave v1.1.1

Code:
[33] public function onCommand(CommandSender $sender, Command $cmd, string $label, array $args):bool
[34] {
[35] if($cmd->getName() === "tjl")
[36] {
[37] if($sender->hasPermission("JoinLeaveTest.cmd"))
[38] {
[39] $sender->sendMessage("JoinLeave ist Aktiv!");
[40] }
[41] }
[42] }
[43]
[44] }

Backtrace:
#0 pmsrc/src/pocketmine/command/PluginCommand(54): JoinLeave\Main->onCommand(object pocketmine\command\ConsoleCommandSender, object pocketmine\command\PluginCommand, string[3] tjl, array[0])
#1 pmsrc/src/pocketmine/command/SimpleCommandMap(248): pocketmine\command\PluginCommand->execute(object pocketmine\command\ConsoleCommandSender, string[3] tjl, array[0])
#2 pmsrc/src/pocketmine/Server(1809): pocketmine\command\SimpleCommandMap->dispatch(object pocketmine\command\ConsoleCommandSender, string[3] tjl)
#3 pmsrc/src/pocketmine/Server(1422): pocketmine\Server->dispatchCommand(object pocketmine\command\ConsoleCommandSender, string[3] tjl)
#4 pmsrc/vendor/pocketmine/snooze/src/SleeperHandler(113): pocketmine\Server->pocketmine\{closure}()
#5 pmsrc/vendor/pocketmine/snooze/src/SleeperHandler(75): pocketmine\snooze\SleeperHandler->processNotifications()
#6 pmsrc/src/pocketmine/Server(2155): pocketmine\snooze\SleeperHandler->sleepUntil(double 1616787449.9529)
#7 pmsrc/src/pocketmine/Server(1992): pocketmine\Server->tickProcessor()
#8 pmsrc/src/pocketmine/Server(1586): pocketmine\Server->start()
#9 pmsrc/src/pocketmine/PocketMine(291): pocketmine\Server->__construct(object BaseClassLoader, object pocketmine\utils\MainLogger, string[44] C:\Users\arese\Desktop\MineWars Test Server\, string[52] C:\Users\arese\Desktop\MineWars Test Server\plugins\)
#10 pmsrc/src/pocketmine/PocketMine(321): pocketmine\server()
#11 pmsrc(11): require(string[99] phar://C:/Users/arese/Desktop/MineWars Test Server/PocketMine-MP.phar/src/pocket)

PocketMine-MP version: 3.18.0 [Protocol 428]
Git commit: 3f6490626319152dca07a5c61a1e94f8d5793d56
uname -a: Windows NT LAPTOP-ASN2539Q 10.0 build 18363 (Windows 10) AMD64
PHP Version: 7.4.15
Zend version: 3.4.0
OS : WINNT, win
Composer libraries:
- adhocore/json-comment 0.1.0@8448076039389f558f39ad0553aab87db3f81614
- daverandom/callback-validator unknown@unknown
- pocketmine/binaryutils 0.1.13@0abee38d4e2861621f262c79a2a3d699d8a697f4
- pocketmine/callback-validator 1.0.3@64787469766bcaa7e5885242e85c23c25e8c55a2
- pocketmine/classloader 0.1.2@9757928424652393b178a3760073113aa7c9911b
- pocketmine/log 0.2.1@830b44a2cf96ef703c550abe64302f230231ca49
- pocketmine/log-pthreads 0.1.3@e477ecf6ec214fdd4415ea1da3fdd9d73bf699ea
- pocketmine/math 0.2.6@43057cb8c179a9859677b496a788db922fd5cfc3
- pocketmine/nbt 0.2.18@9f82ca4d7f97fcd9a566e44b63c4f18a7657ae82
- pocketmine/pocketmine-mp 3.18.0@3f6490626319152dca07a5c61a1e94f8d5793d56
- pocketmine/raklib 0.12.11@9cce458b8bfde3e4dfdbf70c659fc7b7fe26b5c4
- pocketmine/snooze 0.1.5@70b5e7937a06878dd321a3182ceb76d56298f2cd
- pocketmine/spl 0.4.2@6b08b7cf8c4afa17139c9a1b3bf1b408531de161

Loaded plugins:
DevTools 1.13.0 by PocketMine Team for API(s) 3.0.0
JoinLeave 1.1.1 by GeistFan for API(s) 3.0.0, 4.0.0

 

You forgot return true; at the end of the oncommand function

 

Thank you it perfect!!!!