Implement mod + README.md

Author: BlueGradientHorizon

README.md

@@ -0,0 +1,40 @@
+# "Cannot remove from team" workaround
+
+On some buggy servers you may have noticeable lag spikes caused by `Error executing task on client`:
+```text
+net.minecraft.class_148: Main thread packet handler
+	at net.minecraft.class_2600.method_11072(class_2600.java:33) ~[client-intermediary.jar:?]
+	at net.minecraft.class_1255.method_18859(class_1255.java:156) ~[client-intermediary.jar:?]
+	at net.minecraft.class_4093.method_18859(class_4093.java:23) ~[client-intermediary.jar:?]
+	at net.minecraft.class_1255.method_16075(class_1255.java:130) ~[client-intermediary.jar:?]
+	at net.minecraft.class_1255.method_5383(class_1255.java:115) ~[client-intermediary.jar:?]
+	at net.minecraft.class_310.method_1523(class_310.java:1283) ~[client-intermediary.jar:?]
+	at net.minecraft.class_310.method_1514(class_310.java:888) ~[client-intermediary.jar:?]
+	at net.minecraft.client.main.Main.main(Main.java:265) ~[Fabric%201.20.4.jar:?]
+	at net.fabricmc.loader.impl.game.minecraft.MinecraftGameProvider.launch(MinecraftGameProvider.java:470) ~[fabric-loader-0.15.7.jar:?]
+	at net.fabricmc.loader.impl.launch.knot.Knot.launch(Knot.java:74) ~[fabric-loader-0.15.7.jar:?]
+	at net.fabricmc.loader.impl.launch.knot.KnotClient.main(KnotClient.java:23) ~[fabric-loader-0.15.7.jar:?]
+Caused by: java.lang.IllegalStateException: Player is either on another team or not on any team. Cannot remove from team 'Z/Sta/517631'.
+	at net.minecraft.class_269.method_1157(class_269.java:307) ~[client-intermediary.jar:?]
+	at net.minecraft.class_634.method_11099(class_634.java:2029) ~[client-intermediary.jar:?]
+	at net.minecraft.class_5900.method_34173(class_5900.java:129) ~[client-intermediary.jar:?]
+	at net.minecraft.class_5900.method_11054(class_5900.java:14) ~[client-intermediary.jar:?]
+	at net.minecraft.class_2600.method_11072(class_2600.java:24) ~[client-intermediary.jar:?]
+	... 10 more
+```
+
+One thing this mod does is it replaces `IllegalStateException` throwing with `LOGGER.warn()`.
+
+Default `net.minecraft.scoreboard.Scoreboard.removeScoreHolderFromTeam()` (`class_269.method_1157()`) implementation:
+```java
+public void removeScoreHolderFromTeam(String scoreHolderName, Team team) {
+    if (this.getScoreHolderTeam(scoreHolderName) != team) {
+        throw new IllegalStateException("Player is either on another team or not on any team. Cannot remove from team '" + team.getName() + "'.");
+    } else {
+        this.teamsByScoreHolder.remove(scoreHolderName);
+        team.getPlayerList().remove(scoreHolderName);
+    }
+}
+```
+
+Though I'm not a Java coding guru, I don't understand why the exception is thrown on render thread.

src/client/java/com/bluegradienthorizon/cannotremovefromteamworkaround/CannotRemoveFromTeamWorkaroundClient.java

@@ -0,0 +1,28 @@
+package com.bluegradienthorizon.cannotremovefromteamworkaround.mixin;
+
+import net.minecraft.scoreboard.Scoreboard;
+import net.minecraft.scoreboard.Team;
+import org.slf4j.Logger;
+import org.spongepowered.asm.mixin.Final;
+import org.spongepowered.asm.mixin.Mixin;
+import org.spongepowered.asm.mixin.Shadow;
+import org.spongepowered.asm.mixin.injection.At;
+import org.spongepowered.asm.mixin.injection.Inject;
+import org.spongepowered.asm.mixin.injection.callback.CallbackInfo;
+
+@Mixin(Scoreboard.class)
+public class ScoreboardMixin {
+	@Final
+	@Shadow
+	private static Logger LOGGER;
+
+	@Inject(method = "removeScoreHolderFromTeam", at = @At(
+		value = "INVOKE",
+		target = "java/lang/IllegalStateException.<init> (Ljava/lang/String;)V"
+	), cancellable = true)
+	private void removeScoreHolderFromTeam(String scoreHolderName, Team team, CallbackInfo ci) {
+        LOGGER.warn("Player is either on another team or not on any team. Cannot remove from team '{}'. "+
+			"IllegalStateException was not threw due to currently applied \"Cannot remove from team\" workaround.", team.getName());
+		ci.cancel();
+	}
+}

src/client/java/com/bluegradienthorizon/cannotremovefromteamworkaround/mixin/client/ExampleClientMixin.java

@@ -1,11 +1,11 @@
 {
-	"required": true,
-	"package": "com.bluegradienthorizon.cannotremovefromteamworkaround.mixin",
-	"compatibilityLevel": "JAVA_17",
-	"mixins": [
-		"ExampleMixin"
-	],
-	"injectors": {
-		"defaultRequire": 1
+  "required": true,
+  "package": "com.bluegradienthorizon.cannotremovefromteamworkaround.mixin",
+  "compatibilityLevel": "JAVA_17",
+  "mixins": [
+    "ScoreboardMixin"
+  ],
+  "injectors": {
+    "defaultRequire": 1
 	}
 }

src/client/resources/cannot-remove-from-team-workaround.client.mixins.json

@@ -3,39 +3,25 @@
 	"id": "cannot-remove-from-team-workaround",
 	"version": "${version}",
 	"name": "\"Cannot remove from team\" workaround",
-	"description": "This is an example description! Tell everyone what your mod is about!",
+	"description": "Don't throw IllegalStateException \"Player is either on another team or not on any team. Cannot remove from team\"",
 	"authors": [
-		"Me!"
+		"BlueGradientHorizon"
 	],
 	"contact": {
-		"homepage": "https://fabricmc.net/",
-		"sources": "https://github.com/FabricMC/fabric-example-mod"
+		"homepage": "https://github.com/BlueGradientHorizon/cannot-remove-from-team-workaround",
+		"sources": "https://github.com/BlueGradientHorizon/cannot-remove-from-team-workaround",
+		"issues": "https://github.com/BlueGradientHorizon/cannot-remove-from-team-workaround/issues"
 	},
 	"license": "CC0-1.0",
 	"icon": "assets/cannot-remove-from-team-workaround/icon.png",
-	"environment": "*",
-	"entrypoints": {
-		"main": [
-			"com.bluegradienthorizon.cannotremovefromteamworkaround.CannotRemoveFromTeamWorkaround"
-		],
-		"client": [
-			"com.bluegradienthorizon.cannotremovefromteamworkaround.CannotRemoveFromTeamWorkaroundClient"
-		]
-	},
+	"environment": "client",
 	"mixins": [
-		"cannot-remove-from-team-workaround.mixins.json",
-		{
-			"config": "cannot-remove-from-team-workaround.client.mixins.json",
-			"environment": "client"
-		}
+		"cannot-remove-from-team-workaround.mixins.json"
 	],
 	"depends": {
-		"fabricloader": ">=0.15.9",
+		"fabricloader": ">=0.15.7",
 		"minecraft": "~1.20.4",
 		"java": ">=17",
 		"fabric-api": "*"
-	},
-	"suggests": {
-		"another-mod": "*"
 	}
 }